Frequently asked questions

What is TFA?

TFA or trifluoroacetic acid is a very short-chain perfluorinated substance (PFAS). 
TFA is used in many industrial applications (it is a strong acid) and to produce fluorinated molecules.
TFA can be found in various environmental elements (water, air, soil, etc.) as a result of:
•    its direct release into the environment;
•    the degradation of several thousand PFAS released into the environment, including fluorinated gases present in the atmosphere and fluorinated pesticides used in agriculture.

Why worry about TFA?

According to some studies, TFA's high mobility and persistence mean that it is present everywhere in the environment. 
To date, there are no health recommendations based on exposure levels, nor are there any regional, national or even European regulations governing water intended for human consumption.
To understand the situation in Wallonia, it is first necessary to have a comprehensive overview of the TFA content in water intended for human consumption.  

Is there a standard for TFA in tap water?

There is currently no legal limit for TFA in surface water or groundwater, either at the regional, national, or even European level.

In a statement dated August 7, 2024, the European Commission clarified that the health effects of TFA are currently being evaluated by the WHO (World Health Organization), based on the most recent scientific knowledge. Depending on the outcome of this evaluation, the WHO may issue recommendations regarding TFA concentrations in drinking water.

What is the TFA content of tap water in Wallonia?

At the request of the Walloon government, SWDE coordinated a sampling and analysis campaign to assess the presence or absence of TFA in the drinking water supply across the entire Walloon region.
The results of this regional monitoring are available online on the website of the Public Service of Wallonia (Service Public de Wallonie).

According to the opinion provided by the Independent Scientific Council on PFAS (CSI), consulted by the Walloon government, these results do not call into question the potability of the water.

Indeed, the PFAS CSI “unanimously proposes using a guideline value of 2,200 ng/L of TFA in the Walloon drinking water network, provided that only TFA is present in the water sample in question.”

The maximum limit of 100 ng/L for the sum of the 20 PFAS remains applicable alongside this recommendation for TFA. The indicative value for TFA in drinking water proposed by the CSI thus serves as a consultative reference that may be used by the competent authority (SPW-ARNE). Exceeding this guideline value does not compromise the potability of the water but requires an enhanced monitoring plan to identify and eliminate the source of TFA contamination.

On October 17, 2024, the Walloon Government adopted this guideline value of 2,200 ng/L for TFA.

How is TFA detected in water intended for human consumption? 
Detecting TFA in water intended for human consumption requires sensitive and specific analytical techniques due to the low concentrations at which it may be present. 
HPLC-MS/MS is the preferred technique for detecting the presence of TFA in water. It combines the separation of TFA from other molecules present in the water by high-performance liquid chromatography (HPLC) and detection by tandem mass spectrometry (MS/MS) for a highly sensitive and specific measurement.

How is TFA eliminated from water intended for human consumption? 
Conventional techniques used to treat tap water (such as chlorination or filtration) are not effective in removing TFA. It is necessary to use more advanced techniques such as reverse osmosis. This expensive technology consumes energy and water. In addition, managing the TFA concentrate removed from the water raises environmental issues. 

What are chlorates?

Chlorates are chemical compounds primarily formed from chlorine used in the process of disinfecting drinking water. During this disinfection process, chlorates can form as undesirable by-products.

What are the standards for chlorates in distribution water?

European Directive 2020/184 on the quality of water intended for human consumption defines a standard for chlorates that can range between 0.25 and 0.70 mg/l (milligrams per liter). In Wallonia, this standard has been set at 0.25 mg/l. Water distributors have until January 12, 2026, to comply with this new limit.

Are there chlorates in tap water?

Yes, there can be chlorates in tap water, but generally in very low concentrations. Chlorates are by-products that form when chlorine is used to disinfect drinking water. Chlorine is commonly used in water treatment to kill bacteria and other pathogens. However, when chlorine breaks down, chlorates can form.

Is the presence of chlorates in tap water monitored?

Yes, distributors have been required to monitor the presence of chlorates in tap water since January 2024. The SWDE (Walloon Water Management) conducts regular analyses to monitor and adjust water treatments as necessary to comply with the future standard of 0.25 mg/l (milligrams per liter) of chlorates.

How are chlorates detected in distribution water?

Laboratories responsible for water quality control in Wallonia use ion chromatography to analyze chlorates in water. This technique separates the different ions present in the water sample and then measures them separately, including chlorates. This method is highly sensitive and allows the detection of chlorates at concentrations well below regulatory limits.

What solutions are implemented in case of chlorates presence?

Managing chlorate levels in distribution water mainly relies on the level of chlorination of the water and the quality of the reagent used:

Reduce water chlorination without compromising its disinfection effectiveness.
Use high-quality chlorination products. The quality of chlorine degrades over time, leading to the formation of chlorates. This degradation is accelerated by temperature and exposure to light.

The European standards governing the level of pesticides in tap water (and applied in Belgium) are much stricter than the recommendations of the World Health Organization. In Wallonia, only 1/10 of a thousandth of a milligram per litre of water (0.1 µg/l) is allowed per substance and just 1/2 of a thousandth of a milligram per litre of water (0.5 µg/l). 

Compared to the consumption of many other everyday foods, the proportion of pesticides in tap water is very small.
 

In your municipality

Legionellosis is a potentially fatal disease caused by a bacterium, Legionella, which is quite common in nature. It is found in small quantities in most surface waters. It thrives best in warm stagnant water (± 40°C). It cannot survive temperatures above 60°C and dies relatively quickly.

Read more:

Legionellosis: what are the risks?

1. Health risk

1. Can I drink tap water? 

The water that SWDE distributes meets all EU and Walloon health standards.

2. What is the risk of ingesting asbestos? Do we risk the same effects as when we inhale asbestos? 

While the risk of asbestos inhalation has been clearly identified for decades, the same cannot be said for asbestos ingestion, for which the risk is not yet known. To date, there are no EU standards or Walloon legislation on the subject, which is explained by the reassuring conclusions of scientific studies and the World Health Organization (WHO).

3. Can tap water contain asbestos? 

Rarely and in very small quantities. 90% of the pipes in SWDE network are not made of asbestos cement but of other materials (steel, ductile iron, grey iron, PVC, polyethylene, etc.).

There is therefore no risk of water containing asbestos fibres when the water flows through pipes that are not made of asbestos cement. 

When water flows through an asbestos cement pipe, it is possible, under very specific conditions, for asbestos fibres to be released into the water. In this case, the quantities released are infinitesimally small.

4. How can it be said that asbestos cement pipes do not cause the presence of asbestos in tap water? 

The various analyses that SWDE carries out via an accredited laboratory on its customers' taps show that no asbestos fibres have been detected. 

5. Do asbestos cement pipes pose a health risk?

According to current scientific knowledge, the levels of asbestos fibres found in water do not constitute a health hazard. This is why the European Union has not adopted any regulations in this area. 

With the decree of 1 June 2023 amending various provisions concerning the quality of water intended for human consumption, Wallonia has chosen to go further by setting a guide value of 1 million fibres per litre using a method derived from NFX 43-050, with a quantification limit of less than or equal to 10,000 fibres per litre.

The United States has set a health standard of 7 million fibres per litre. 

SWDE has never encountered such levels in the water analyses it carries out after taking samples from its customers' taps.

6. Can I inhale asbestos from tap water? 

Under certain conditions, water intended for human consumption can be aerosolised (air from showers, etc.) and inhaled in very small quantities. As the asbestos fibre content in the tap water is zero or particularly low, the amount of asbestos fibre inhaled would be minuscule.

7. Won't the wear and tear of the asbestos cement pipes cause even more asbestos to be released into the water? 

SWDE monitors our asbestos cement pipe network through targeted analysis campaigns. If abnormal wear and tear of our pipes were to endanger the health safety of our customers, the SWDE would make every effort to renew them as a matter of priority.

8. Can roof, cistern or well water contain asbestos? 

Water that comes into direct contact with asbestos cement materials could, under certain conditions, contain asbestos fibres. For example, if the asbestos cement material is brittle (degraded by temperature variations between winter and summer) and the water that comes into contact with it has aggressive properties (which is characteristic of rainwater), then it is possible for the water collected to contain asbestos fibres.

The risk of harvested rainwater containing asbestos is therefore much higher than that for tap water. 

9. Does SWDE test for asbestos in all municipalities? 

There are municipalities where there are no asbestos cement pipes. It is therefore unnecessary to carry out special tests in these municipalities. Since September 2023, SWDE, with the support of the Walloon region, has taken the initiative of carrying out water quality checks in every municipality served by SWDE where part of the network is made of asbestos cement. 

10. Can I request a free analysis? 

SWDE can accommodate special requests for analysis within the framework of the current sampling campaign, as long as they are representative enough. 

If the request cannot be part of a sampling campaign, the customer can request a water quality test at their own expense from a specialised laboratory. 

11. What is the treatment to remove asbestos from water? 

The asbestos fibre content in the water supply is zero or very low. It is therefore not necessary to treat the water. 

12. Why check at hydrants and not just at customers' taps? 

The only point of compliance for water intended for human consumption is our customers' kitchen taps.

 As part of an internal study conducted in 2018, we carried out water quality checks both at hydrants and also at our customers’ meters and kitchen taps. Samples taken at the hydrants do not provide a representative picture of the quality of the water distributed to our customers. 

Our sampling campaigns now target our customers' taps to obtain a representative picture of the water consumed by our customers. 

13. Why do your checks show that the asbestos found at the hydrants is not found at the taps? 

Hydrants have a dead volume between the pipe and the hydrant outlet. The water contained in the dead volume is stagnant and particles can become lodged there. When we take samples at hydrants, the sample taken may not be representative of the water actually distributed to our customers, because some of the water taken is stagnant water containing certain particles, including asbestos fibres.

The only point of compliance for water intended for human consumption is our customers' kitchen taps. As part of an internal study conducted in 2018, we carried out water quality checks both at hydrants and also at our customers’ meters and kitchen taps. Samples taken at the hydrants do not provide a representative picture of the quality of the water distributed to our customers. Our sampling campaigns now target our customers' taps to obtain a representative picture of the water consumed by our customers. 

14. Is it dangerous to wash clothes with tap water containing asbestos? 

The asbestos fibre content in the water is, where applicable, infinitesimally small. It is therefore not dangerous to wash your clothes with tap water supplied through asbestos cement pipes, as the risk of finding asbestos fibres on your clothes is very limited.

2. Information.

15. Why did you hide the positive asbestos water tests?

Water analyses showing the presence of asbestos fibres in the water have not been hidden. The positive tests were not specifically communicated because they did not relate to the water in the customers' taps. SWDE has provided this data in a transparent manner when requested.

16. What information will you be providing? Will you publish your new analyses? 

SWDE is currently conducting a new water quality monitoring campaign. The results obtained are communicated to the municipalities and the Walloon Region. 

17. Will I be warned if there is asbestos in my tap water? 

If the analysis campaigns we carry out reveal a health risk for our customers, a specific communication will be sent to the customers concerned.

18. Why did you hide the presence of asbestos cement pipes? 

SWDE has never made a secret of the presence of asbestos cement pipes. The FAQ tab on its website (swde.be under "Frequently Asked Questions") has been openly addressing the subject for many years.

19. Why not disclose the streets where these pipes are located?

In its computerised mapping system, SWDE has the nature (material) of all the pipes in its networks, including those made of asbestos cement. The exact mapping of the pipelines is not provided for reasons of network integrity and public safety. Neither a diagram nor a list of streets is representative of a risk related to water quality as it flows through the pipes, since, for example, there may be pipes constructed of different materials in the same street.

3. Pipes

20. Why are there asbestos cement pipes?

In the aftermath of the 2nd World War (1940-1945), the demand for building materials was enormous and many small and medium-sized municipalities were equipped with a drinking water network. Asbestos cement pipes produced in Belgium were an innovative alternative to the much sought-after materials steel and grey cast iron. In addition to being lighter, asbestos cement pipes had useful characteristics in terms of compressive strength, tensile strength and bending strength, as well as an absence of internal corrosion which, with metal pipes, can cause coloured water over time. 

No more asbestos cement pipes have been laid since the late 1970s.

21. Where are asbestos cement pipes laid? 

The distribution of this type of pipe throughout Walloon territory is not uniform, as some municipalities have a network composed of a high percentage of asbestos cement pipes, while others have none at all. 

In its computerised mapping system, SWDE has the location, nature (material) and other characteristics such as diameter, date of laying, etc. of all the pipes in its networks, including those made of asbestos cement. 

22. How does SWDE know the nature of the distribution pipes? 

When pipe-laying work is carried out, a survey plan is drawn up at the end of the works. It lists all the components of the network (pipes, valves, hydrants, etc.), which are identified either by reference to features visible on the ground or by topographical surveys that allow them to be geolocated. All this information is transcribed into SWDE's geographic information system (GIS). 

23. Why have all these pipes not already been systematically replaced? - Why not draw up a specific plan for the urgent replacement of asbestos cement pipes? - What is your plan to replace these pipes in the coming years? How many km will you be replacing over the next 5 years?

There is no need to plan a systematic replacement of asbestos cement pipes rather than any other materials, as no scientific study has been able to demonstrate that oral ingestion of asbestos fibres in drinking water would have an impact on health, a conclusion which is confirmed by the World Health Organization (WHO).

In general, asbestos cement is insensitive to internal corrosion and stray current corrosion. 

SWDE’s pipe replacement strategy incorporates the “asbestos” parameter. SWDE uses a multi-criteria tool to define renewal priorities, taking into account the nature of the pipes and their age. SWDE invests €100 million each year in the renewal of its infrastructure, of which more than €60 million is spent on pipes.

24. What are asbestos cement pipes replaced with? 

The new main pipes laid in the networks are usually made of ductile cast iron and PVC, and more rarely of electro-weldable polyethylene or steel. 

25. What measures does SWDE take to deal with asbestos work sites? 

SWDE has an aggressive and consistent policy to protect its workers when working with asbestos. It has strict and safe working practices in place when cutting asbestos cement pipes. On the basis of internal procedures and operating methods, it provides staff with annual training in asbestos-related risks, as well as a manual reminding them of the precautions to be taken with regard to the workers and people living in the immediate vicinity of the site during interventions, as well as a kit of single-use personal protective equipment.

In addition, SWDE also informs its subcontractors through the Health and Safety Prevention Plan (HSPP) attached to the specifications governing the contracts. It also provides training sessions on asbestos risks and precautions. 

Finally, SWDE’s internal department for prevention and protection in the workplace (SIPPT) and managers carry out site visits throughout the year, during which a predefined list of safety points are checked. The use of the "asbestos kit" is a recurring point in the rating, which is followed as an objective for its intervention teams. 

26. Are customers in the vicinity of an asbestos site warned?

The measures taken on the sites to avoid the projection of asbestos fibres into the surrounding air, such as the use of slow saws and spraying continuously with water during cutting, as well as the location in a trench, sheltered from the wind, do not require the local residents to be informed. 

On the other hand, sites of this type must be notified to the relevant Regional Directorate for Workplace Welfare Control (FPS Employment, Labour and Social Dialogue) in order to check that the legislation and, in particular, the worker protection measures are respected and correctly implemented. 

27. Is it necessary to run the tap water more than usual after replacing an asbestos cement pipe? 

After work has been carried out on the network, when it is brought back into service, the water engineers purge the water through the hydrants to eliminate the cloudy or coloured water that is inevitably generated by the work. 

As a general rule, whatever the nature of the pipe, it is advisable to run the tap water for a few moments to eliminate any cloudy or coloured water that may have entered the connections and that has not been purged at the street level. There is no reason to do this more extensively when working on asbestos cement pipes.  

28. Where does asbestos waste from your asbestos cement pipe replacement sites go?

The disposal of waste materials containing asbestos is subject to legislation that is reflected in the operating procedures applied within SWDE. From the launch of the work, the waste is packaged in specific containers with the personal protective equipment used by the personnel. They are collected by an approved firm for disposal in centres that are themselves approved for this type of waste. 

29. Does SWDE take the opportunity to replace asbestos cement pipes on roadworks carried out by other road or network managers? 

SWDE systematically examines the appropriateness of renewing its pipes when road managers or other underground installation contractors are carrying out works under the terms of the legislation on worksite coordination (POWALCO). However, this alone is not enough to decide to renew the pipes. 

The choice is made on the basis of a multi-criteria tool that allows the decision to be made objectively, regardless of the pipe material. Particular attention is paid to construction sites where the nature of the work could weaken the asbestos cement pipes. 

30. Can a municipality or the region require you to replace an asbestos cement pipe if it covers the cost? 

Although the network is owned by SWDE and pipe renewals are carried out objectively using a multi-criteria prioritisation tool, there is nothing to prevent a municipality or the Region from financing a pipe replacement. However, the project can only be carried out by SWDE, in accordance with its technical specifications.

31. Why is it that asbestos fibres can sometimes be detected when sampling fire hydrants, but not at customers' taps? 

Hydrants are special elements of the network. Their location in the branch of the pipe and their configuration mean that they are like small "dead ends" of stagnant water where fibres can become trapped and be released when the network is purged.

Main pipe in which water circulates continuously.

The body of the hydrant, which is automatically drained of its water (protection against freezing) when the hydrant is closed.

Location of the valve which isolates the body (without water) from the bypass and the duckfoot bend which remain under water.

and that are like small "dead ends" where fibres can become lodged and remain trapped and be released when the network is purged.

The body of the hydrant, which is automatically drained of its water (protection against freezing) when the hydrant is closed.

Location of the valve which isolates the body (without water) from the bypass and the duckfoot bend which remain under water.

and that are like small "dead ends" where fibres can become lodged and remain trapped and be released when the network is purged.

Particular attention is paid to the presence of lead in drinking water. At the end of 2013, the European Union set a maximum lead content in tap water of 10 µg/l.

We are doing our utmost to meet this standard. 

To find out more, visit the page “Lead in tap water? ”

1. What are pesticide metabolites?

Metabolites are chemical molecules produced by the breakdown of pesticides used in agriculture or by private individuals.

A distinction is made between "relevant" and "irrelevant" metabolites, depending on their properties. A "relevant" metabolite is a molecule which, because of its toxic activity or properties, is considered in the same way as a conventional pesticide. An "irrelevant" metabolite is one whose activity is altered in such a way that it is not toxic. Irrelevant metabolites do not retain the same activity as their parent substance or pose a health risk to consumers.

Metabolites are chemical molecules produced by the breakdown of pesticides used in agriculture or by private individuals.

A distinction is made between "relevant" and "irrelevant" metabolites, depending on their properties. A "relevant" metabolite is a molecule which, because of its toxic activity or properties, is considered in the same way as a conventional pesticide. An "irrelevant" metabolite is one whose activity is altered in such a way that it is not toxic. Irrelevant metabolites do not retain the same activity as their parent substance or pose a health risk to consumers.

2. What products contain pesticide metabolites?

Metabolites do not exist in their natural state, just like the pesticides from which they are derived. These come from the petrochemical industry and are used both in agriculture and by private individuals.

3. Are metabolites dangerous to health?

Certain metabolites can be recognised as toxic. They are then treated as relevant metabolites and therefore subject to standards. 

There is very little toxicity data on irrelevant metabolites. They are monitored as a preventive measure.

4. Why are metabolites found in the environment?

Once pesticides are released into the environment, they break down. A part of them is converted into metabolites. Most of these are mobile and persistent and can therefore be found in different water matrices, such as surface water or groundwater.

For further information, contact http://etat.environnement.wallonie.be/contents/indicatorsheets/EAU%2014.html

The Walloon Government Decree of 1 June 2023 sets out the following standards: 

6. Does tap water contain irrelevant metabolites?

The comprehensive controls planned for 2024 will provide an answer to the question of the presence of irrelevant metabolites in tap water. The results will gradually be made available to SWDE customers through the water quality sheet available on the website and with their annual bill. This will supplement the information already available on all pesticides.  

7. How are pesticide metabolites detected in drinking water? 

Metabolites are analysed using high-performance laboratory equipment. The technology used is high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS-MS). This technique enables metabolites to be separated, identified and quantified.

8. What solutions are deployed in the event of the presence of metabolites? 

Solutions need to be analysed on a case-by-case basis. On the one hand, two water resources can be mixed to reduce the pesticide (metabolite) content in the drinking water. There are also water treatment solutions, such as activated carbon filtration. 

Activated carbon has a high adsorbent capacity, meaning that it retains on its surface certain molecules (including pesticide metabolites) that come into contact with it.
The effectiveness of the activated carbon treatment is monitored and evaluated over time. Activated carbon is regenerated as soon as its adsorption capacity begins to decrease.

9. What information is provided if the standard for pesticide metabolites is exceeded?  

If the standard for pesticide metabolites is exceeded, this is treated in the same way as any other event affecting drinking water quality.

The Walloon Region does not issue health recommendations.

10. What are the regulations for other foods?

For more information on EU and federal legislation concerning the control of pesticide residues in foodstuffs, click on the following link to the FASFC website 

1. Is tap water safe to drink?

Tap water is safe to drink if it meets the quality requirements defined at EU level and then transcribed into the legislation of each Member State. And so, yes, tap water in Wallonia is safe to drink in the sense that it meets the health standards laid down by the Walloon Region. These standards are regularly revised, as has recently been the case for PFASs in particular. 

To date, PFAS levels in all SWDE networks are below the future parametric value (drinking water standard) of 100 nanograms per litre (ng/l).

2. What are the PFAS standards for tap water?

Standards for PFASs in tap water are recent. In the light of advances in scientific knowledge, on 16 December 2020, EU Directive 2020/2184 on the quality of water intended for human consumption made it compulsory, from 2026, to comply with a parametric value of 100 nanograms (i.e. 1/10,000,000th of a gram) per litre for the sum of measured concentrations of 20 PFASs specifically identified in the directive.

By way of comparison, the maximum levels of PFASs in foodstuffs are as follows

        Commodity                                                                                sum of the 4 PFASs*

• Eggs                                                                                       1,700 ng/kg
• Fish flesh intended for infant food                                       2,000 ng/kg
• Meat                                                                                      1,300 ng/kg
• Game                                                                                     9,000 ng/kg

* PFOS, PFOA, PFNA and PFHxS

As far as milk is concerned, the Federal Agency for the Safety of the Food Chain (AFSCA) has issued a recommendation of 6,000 nanograms/kg for PFOS and 60,000 nanograms/kg for PFOA. Find out more here.

3. Is there a standard in force in Wallonia for PFASs in water?

Not yet. The standard will come into force on 12 January 2026.

Wallonia transposed Directive 2020/2184 in 2023 with a decree dated 20 April 2023 and a Walloon Government order dated 1 June 2023.

This order amending various provisions concerning the quality of water intended for human consumption came into force on 6 October 2023.

It stipulates that, by 12 January 2026 at the latest, the necessary measures must be taken to ensure that the PFAS content does not exceed 100 nanograms/litre in water intended for human consumption.

4. American standards have often been compared with those of the European Union. What are these standards? 

Until recently, there was no standard in the United States for PFASs in tap water. The EPA - the US Environmental Protection Agency - had issued a recommendation for 2 PFASs: PFOS and PFOA. American water distributors were free to apply it or not.

Since 10 April 2024, the EPA has issued a standard.  American water distributors have a maximum of 3 years to comply. This standard covers 5 substances for which the EPA has established a threshold value that must not be exceeded and a recommendation: 

From 2026, the European Union will introduce a threshold of 100 nanograms per litre for the sum of concentrations of 20 PFASs (including PFOA, PFOS, PFHxS and PFNA).               

The European Health Agency (EFSA) also recommends not exceeding a value of 4 nanograms per litre for the sum of the 4 PFASs of "greatest concern", i.e. PFOA, PFOS, PFHxS and PFNA.  In the American standard, the threshold for the sum of the same 4 PFASs is set at 28 nanograms per litre.
 

PFASs in water distributed in Wallonia

CHIÈVRES

5. Does the water distributed in Chièvres comply with the future PFAS standard of 100 nanograms/litre?

Yes, as the analyses carried out by an accredited laboratory attest, the water distributed in Chièvres complies not only with current legislation on water quality but also with the future PFAS standard of 100 nanograms/litre.

6. What solution has been put in place to reduce the level of PFASs found in the P1 well at Chièvres?

SWDE has installed an activated carbon filtration system at the P1 well in Chièvres. Activated carbon has a high adsorption capacity, meaning that it retains on its surface certain molecules (including PFASs) that come into contact with it.

The effectiveness of the activated carbon treatment is monitored and evaluated over time. Activated carbon is regenerated as soon as its adsorption capacity begins to decline.

7. Why is water never PFAS-free?

Treatment of the water from the Chièvres well with activated carbon has significantly reduced PFAS concentrations. The PFAS content is still 4 times lower than the future standard of 100 nanograms per litre.

8. Are the PFASs of greatest concern still present in the tap water?

No. Analyses show values for PFOA, PFNA, PFHxS and PFOS of less than one nanogram per litre.

The water distributed in Chièvres complies not only with future regulations but also with health recommendations, which are even stricter.

The EFSA (European Food Safety Authority) recommendation is that the cumulative concentration of the 4 PFAS molecules of greatest concern should not exceed 4 nanograms/litre.

In Chièvres, the concentrations measured for the 4 PFASs of greatest concern are below one nanogram per litre, i.e. below the detection limits of the measuring equipment.

9. Why are the values published today for Chièvres lower than in previous reports?

All the values published since November are below the future standard of 100 nanograms per litre.

PFAS data available on the website www.swde.be represent a median value for the results of analyses carried out since September 2023, when regional monitoring began. 

The values published previously for Chièvres and, more broadly, the distribution zone n°1098 were the median value of the results recorded over the last 12 months.  They therefore also included analyses carried out before the installation of activated carbon filters at the outlet of the Chièvres catchment and were therefore not very representative of the current situation. 

The values published for PFASs will therefore continue to evolve. They will be representative of the quality of the water consumed by the public.  

10. Why not abandon the Chièvres well and use another source of water instead?

Use of the Chièvres well has been significantly reduced. It can only be shut down temporarily, as it is necessary to guarantee the continuity of the water supply. This is why SWDE has invested in activated carbon filtration treatment at the Chièvres catchment to ensure that the water meets future PFAS standards.

The Chièvres water tower is fed by the Chièvres well and the Dendre pipeline. All the water from the Chièvres well is treated with activated carbon. 

SWDE is looking into the possibility of finding one or several structural solutions to dispense with the Chièvres well. 

11. What happens if the Chièvres well is temporarily shut down?

The Chièvres well is shut down for a few hours to replace the activated carbon filters. The water tower is filled to maximum capacity beforehand to ensure a continuous water supply.

12. Why are PFASs present in the Chièvres distribution well?

The origin of the presence of PFASs in the Chièvres distribution well has not yet been established. PFASs are diffuse and persistent substances, present in a large number of products, including fluorinated fire-extinguishing foams. These fire-fighting foams were often used on military bases. It is therefore possible that the contamination came from the nearby Chièvres military base.

The ISSeP (Institut Scientifique de Service Public) has been commissioned by the Walloon Government to carry out the necessary research to identify the origin of the PFASs in the Chièvres well.

RONQUIÈRES

13. Is the water safe to drink in Ronquières?

Yes, the water is safe to drink in Ronquières. It complies with current quality legislation and the future standard of 100 nanograms/litre.

14. Has the future standard of 100 nanograms/litre been exceeded in the water distributed in Ronquières?

A single result in November 2023 showed that the future standard of 100 nanograms/litre had been exceeded in the water distributed in Ronquières. The legal procedure for verification and increased surveillance has been activated. On the one hand, the same samples have been re-analysed: their results are below 100 ng/l. In addition, new samples were taken and the results of the analyses showed PFAS levels of less than 100 ng/l. These results are in line with those communicated by Vivaqua about the Hainaut Feeder. 

The median value since 22 February 2024 is 82 ng/l.  Analyses will continue to be carried out regularly at Ronquières. This median value will therefore continue to evolve.

15. Will the PFAS content in Ronquières water decrease?

SWDE is looking for technical solutions to reduce the PFAS content in the water it supplies. It remains in contact with the municipality of Braine-le-Comte, Vivaqua and the regional authorities.

Vivaqua has announced that it has recently replaced the activated carbons used to treat the water in a series of wells. The Brussels water company has confirmed that it is managing to keep the level at 75 ng/l at the Ecaussinnes exit. 

THE HAINAUT FEEDER

16. What is the Hainaut Feeder? 

The Hainaut Feeder is a Vivaqua pipeline from its catchments in Nimy and Ghlin. It goes all the way back to the Brussels region. Vivaqua supplies this water to SWDE, IDEA, in BW, De Watergroep and Farys to supply part of their distribution networks. 

The SWDE is connected to Vivaqua's Hainaut Feeder to supply water to distribution zones 1102, 1106, 1147 and 1360. The municipalities concerned in whole or in part are Braine-l'Alleud, Braine-le-Château, Braine-le-Comte (Ronquières - see previous point), Ecaussinnes, Ittre, Le Roeulx (a few connections), Seneffe (a few connections), Soignies (a few connections) and Tubize.

What is your distribution area? What is the quality of the water supplied there? How can I view the full analysis reports?  Go to this page to find the answer to these three questions.

17. Does the water from Vivaqua's Hainaut Feeder comply with the future PFAS standard?

Vivaqua undertakes to deliver water that complies with the standards in force in Wallonia, including the ministerial instruction of 30 November 2023 to comply with the standard of 100 ng/l for the sum of 20 PFASs.

Vivaqua confirms that this threshold has not been exceeded in weekly analyses since 2023.

A verification procedure was carried out in November 2023 and February 2024 following the receipt of isolated analysis results (one result in November 2023 in Ronquières and 3 results in February 2024, including 2 in Virginal and 1 in Tubize) showing that the future standard of 100 nanograms/litre had been exceeded in the distributed water. 

Firstly, the same samples were re-analysed. Their results are below 100 ng/l. New samples were also taken. Analysis results show PFAS levels below 100 ng/l. These results are in line with those communicated by Vivaqua for the Hainaut Feeder. 

18. Why regional biomonitoring for people supplied with water in Wallonia by the Hainaut Feeder? 

The water distributed today has PFAS levels below the future standard in all areas. This is also the case for water from Vivaqua’s Hainaut Feeder.

The general monitoring of the water distributed in Wallonia, carried out between September and December 2023, showed that the PFAS levels in the water from Vivaqua's Hainaut Feeder are higher on average than those observed in the water distributed in most of the other distribution zones, while still complying with the future PFAS standard. 

In December 2023, Vivaqua informed the regional authorities and SWDE that the future standard of 100 ng/l had been exceeded on 10 occasions for the sum of 20 PFASs between October 2021 and December 2022. The highest exceedance was measured at 147 ng/l. 

This is why, following the example of other areas where the future PFAS standard has been exceeded in the past, Wallonia has decided to allow people who have consumed water supplied by Vivaqua's Hainaut Feeder to take part in biomonitoring (a blood sampling and analysis campaign).

IN WALLONIA

19. How are PFASs detected in drinking water?

PFASs are analysed using high-performance laboratory equipment. The technology used is high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS). This technique can be used to separate, identify and quantify PFASs in samples.

The concentration levels sought are particularly low. They require high-performance equipment and rigorous analysis, as these substances, which are also present in laboratories, can interfere with the final results.  

To date, there is no accredited laboratory in Wallonia to analyse the 20 PFASs provided for in the future regulations. SWDE analyses are currently carried out by a laboratory in Germany.

20. Does tap water in Wallonia contain PFASs?

In 2018, a study commissioned by the Walloon Region and conducted by a consortium of laboratories of which SWDE is a member was finalised. The results are available on the Walloon public service website (IMHOTEP and BIODIEN research programmes - Water Framework Directive in Wallonia - SPWARNE © HB). The conclusions of this study were reassuring about the likelihood of PFASs being found in water intended for human consumption.

The future PFAS standard of 100 nanograms/litre was exceeded at the Chièvres well until early 2023. Following the commissioning of two activated carbon filter units to treat the water from this well, since April 2023 the water supplied to the Chièvres water tower has met future requirements in terms of maximum permissible PFAS content.

In September 2023, the Walloon Government decided to launch a monitoring programme for PFASs in tap water throughout Wallonia.

21. What is regional PFAS monitoring in tap water?

On 5 September 2023, the Walloon Government commissioned SWDE to coordinate analyses of PFAS levels in water intended for human consumption and in certain raw water suitable for drinking throughout Wallonia.

This work is being carried out in collaboration with SPW-ARNE and all the water distributors. 

22. What is the aim of regional PFAS monitoring of tap water?

Monitoring has a number of objectives:

1. draw up an exhaustive inventory of PFAS levels in water intended for human consumption (at the tap), as well as in certain raw waters suitable for drinking;
2. continuous monitoring of PFAS levels in water intended for human consumption;
3. on the basis of the results obtained, identify the water catchment(s) responsible for the presence of PFASs in tap water;
4. make the results available to water distributors so that they can take the necessary steps to guarantee consumer health safety.

23. What are the results of regional monitoring?

Regional PFAS monitoring began in September 2023.

Since 27 November 2023, SWDE has had results for its entire network (278 distribution zones). The entire SWDE network complies with the future PFAS standard (100 ng/l), which will come into force in January 2026.

On 11 December 2023, the results for all 640 distribution zones in Wallonia will be available. 

24. Are PFAS results available for tap water?

Water quality results are made available by the distributors.

For several years now, SWDE has been making water quality analysis reports available online. They have just been supplemented with the median PFAS value with regard to the future standard of 100 nanograms/litre for all the networks it manages.

25. How can I view the results available?

If your distributor is SWDE, here's how you can consult the results of the analyses according to your location. 

If you are not connected to the SWDE network, we advise you to contact your water distributor for further information.

26. What information will be provided if the future PFAS standard of 100 nanograms/litre is exceeded?

SWDE now applies the PFAS standard as if it were already in force. The municipality and the customers concerned are informed if an analysis result shows that the future PFAS standard of 100 nanograms/litre has been exceeded. 

27. What are the health recommendations if the future PFAS standard of 100 nanograms/litre is exceeded?

Since 14 November 2023, if the threshold of 100 nanograms/litre is exceeded, the Walloon Region recommends that residents concerned should no longer drink tap water. Because of the endocrine disrupting potential of certain PFASs and the precautionary principle, this recommendation is reinforced in particular for the following target groups: children and adolescents under 18, women of childbearing age, pregnant and breastfeeding women.

Based on advances in scientific knowledge, the competent health authorities will specify these recommendations (alternatives to mains water, different uses of tap water, etc.). The FAQ provided by the Walloon Region will be completed on this subject. It can be consulted at PFAS - Environment-Health Portal (wallonie.be).

28. What solutions are deployed in the event of PFASs in the mains water supply?

Suitable treatments exist and are effective in limiting the presence of PFASs in the mains water supply, including activated carbon filtration.

Activated carbon has a high adsorption capacity, meaning that it retains on its surface certain molecules (including PFASs) that come into contact with it.

The effectiveness of the activated carbon treatment is monitored and evaluated over time. Activated carbon is regenerated as soon as its adsorption capacity begins to decrease.

SWDE did not wait for the PFAS crisis before installing activated carbon filters. Some catchment sites are already equipped with them, and some have been for decades. SWDE continues to invest regularly in this technique and in other treatments (e.g. nanofiltration) needed to make water safe to drink.

Priorities are set in accordance with the analyses carried out as part of health risk management. 

The use of activated carbon filters to make water drinkable is common practice in many countries, including Belgium. These filters are effective at removing various organic contaminants, chemicals and bad tastes and odours from water, making it safer and more pleasant to drink. 

29. Can we trust the results of the analyses communicated by SWDE on PFAS levels in our tap water?

All water analyses provided by SWDE are carried out by an ISO 17025-accredited laboratory. 

ISO 17025 is an international standard that recognises the competence of laboratories to produce valid results.

Consequently, all the results communicated by SWDE in a transparent manner via its website are entirely reliable.

As regards PFASs, no Walloon laboratory is currently capable of analysing the sum of 20 PFASs on its own. It is therefore foreign laboratories that carry out analyses of PFAS content in drinking water.

THE PFASs

30. What does PFAS mean?

PFAS stands for "per- and polyfluoroalkylated substances". This is a large family of molecules comprising almost 10,000 chemical compounds. What these compounds have in common is that they all consist of a chain of carbon atoms to which fluorine atoms have been added.

31. What products contain PFASs?

PFASs are not natural substances. They are manufactured by the chemical industry for their special properties, such as their non-stick, waterproofing and heat-resistant properties. This is why these substances have been widely used in everyday products such as frying pans, waterproof clothing, paper and packaging for food use, and fire-fighting foams.

32. Are PFASs a health hazard?

Given the wide range of molecules making up the PFAS family, the information available on the toxicity of these substances is limited to a small number of the most commonly used molecules.

Toxicological effects of certain PFASs on the liver, immune system, kidneys, reproductive system, etc. have been reported in animals. Similar effects have been observed in humans.

Scientific knowledge of the effects on health continues to grow steadily.

For more information on this subject:  http://environnement.sante.wallonie.be/pfas

33. Why are PFASs found in the environment?

In chemistry, the bond between a carbon and a fluorine atom is extremely strong, which means that PFASs degrade very little naturally and are therefore very persistent in the environment.

This persistence, coupled with widespread use by industry and private individuals since the 1950s, means that PFASs accumulate everywhere in the environment, particularly in water, over time.

What is vinyl chloride monomer?
Vinyl chloride monomer (VCM) is a chemical compound made up of chlorine, carbon, and hydrogen. It may be found in drinking water due to its release from PVC water pipes installed before the 1980s.

What is the standard for vinyl chloride monomer in drinking water?
For over 20 years, the standard for vinyl chloride monomer has been 0.50 µg/l (micrograms per liter).

Is there vinyl chloride monomer in tap water?
Very rarely and only in extremely small amounts. No exceedances of the standard have been observed.

Is the presence of vinyl chloride in tap water monitored?
Yes, analyses carried out in Wallonia show a vinyl chloride concentration below the detection limit of the method (0.10 µg/l), which is itself well below the parametric value of 0.5 µg/l.
These results are not published on our website as they concern specific pipeline sections rather than distribution zones, for which water quality is reported.

How is vinyl chloride detected in drinking water?
Laboratories use the accredited method according to standard NBN EN ISO 15680:2003 (Water quality – Determination of a number of monocyclic aromatic hydrocarbons, naphthalene, and various chlorinated compounds by gas chromatography after degassing, trapping, and thermal desorption).

What measures could be taken if vinyl chloride is detected?
On the one hand, PVC pipes would need to be replaced with other materials (grey cast iron, PVC without VCM, etc.) to eliminate the source of contamination. On the other hand, water treatment options such as activated carbon filtration or ion exchange resins could be considered.