Sometimes taste problems can arise after water has been boiled. As a general rule, if your drinking water is satisfactory prior to boiling and you then notice a taste after boiling the cause of the problem is usually the kettle.
Boiling water in a saucepan on your hob or stove will help determine if your kettle is the cause of the unusual taste.
If you have a new kettle, allow a layer of limescale to build up inside it by boiling and then discarding the water a few times. Only boil the required amount of water each time. Do not re-boil water, rather discard it, rinse the kettle and fill with fresh water. Also try to avoid frequent de-scaling of the kettle.
If you've tried this but are still concerned, or you'd like more advice you should contact your water supplier.