First of all, it is important to identify the origin of this "musty" or mouldy taste. It can come from the public supply network or from the pipes inside the house. To find out, draw water immediately after the meter at the stopcock. If this bad taste is present at the meter, contact us.
If the water does not have a taste or odour problem at the point where it comes into the building, the problem is in the internal installation. In this case, a purging of the internal pipes should help return it to a normal situation.