The groundwater which forms much of Britain's drinking water is so polluted with nitrates that additional equipment will need to be installed to purify it in treatment works.
The costs of the additional technology are likely to lead to a rise in water bills.
Nitrate is a potent algal nutrient and leads to eutrophication - both in nature and in the aquarium. Tapwater is now so poor that many fishkeepers are switching to purified water, such as RO, rather than relying on the water authority to provide good quality water. Water authorities currently need to supply water containing less than 50 ppm of nitrate.
According to a report in The Guardian, customers currently pay around 7 for the removal of nitrate and pesticides. These costs could increase to 25 or more over five years.