Guidelines On Drinking Water Standards UK

Drinking water must be ‘wholesome’ and this is defined in law by standards for a wide range of substances, organisms and properties of water in regulations.

The standards are set to be protective of public health and the definition of wholesome reflects the importance of ensuring that water quality is acceptable to consumers.

There is good agreement worldwide on the science behind the setting of health based standards for drinking water, and this expert evidence is documented by the World Health Organisation in the Guidelines for Drinking Water Quality.

The legal standards in the UK are explained fully in the Water Supply (Water Quality) Regulations 2016.

Below is a brief guide to the regulations and was correct at the time of publication. It is advisable to double check these standards with any amended version of the UK Government regulations above

National Requirements

ParametersMaximum Valueunits of Measurementpoint of compliance
Aluminium200µgAl/lConsumers’ taps
Colour20mg/l Pt/CoConsumers’ taps
Iron200µgFe/lConsumers’ taps
Manganese50µgMn/lConsumers’ taps
Odour<1 at 25 °CDilution numberConsumers’ taps
Sodium200mgNa/lConsumers’ taps
Taste<1 at 25 °CDilution numberConsumers’ taps
Tetrachlormethane3µg/lConsumers’ taps
Turbidity4NTUConsumers’ taps


ParametersMaximum Valueunits of Measurementpoint of compliance
Antimony5.0µgSb/lConsumers’ taps
Arsenic10µgAs/lConsumers’ taps
Benzene1.0µg/lConsumers’ taps
Benso(a)pyrene0.010µg/lConsumers’ taps
Boron1.0mgB/lConsumers’ taps
Bromate10µgBrO3/lConsumers’ taps
Cadmium5.0µgCd/lConsumers’ taps
Chromium50µgCr/lConsumers’ taps
Copper(ii)2.0mgCu/lConsumers’ taps
Cyanide50µgCN/lConsumers’ taps
1,2 dichloroethane3.0µg/lConsumers’ taps
Fluoride1.5mgF/lConsumers’ taps
Lead(ii)10µgPb/lConsumers’ taps
Mercury1.0µgHg/lConsumers’ taps
Nickel20µgNi/lConsumers’ taps
Nitrate50mgNO3/lConsumers’ taps
Nitrite0.50mgNO2/lConsumers’ taps
 0.10 Treatment works


ParametersMaximum Valueunits of Measurementpoint of compliance
Aldrin0.030µg/lConsumers’ taps
Dieldrin0.030µg/lConsumers’ taps
Heptachlor0.030µg/lConsumers’ taps
Heptachlorepoxide0.030µg/lConsumers’ taps
Other Pesticides0.10µg/lConsumers’ taps
Pesticides:Total0.50µg/lConsumers’ taps
Polycyclic aromatic hydrocarbons0.10µg/lConsumers’ taps
Selenium10µg/lConsumers’ taps
Tetrachloroehtane10µg/lConsumers’ taps
Trichloroethane10µg/lConsumers’ taps
Trihalomethanes100µg/lConsumers’ taps
Vinyl chloride0.50µg/lConsumers’ taps


ParametersMaximum Valueunits of Measurementpoint of compliance
Coliform bacteria0number/100mlTreatment works
Enterococci0number/100mlConsumers’ taps
Escherichia coli (E.coli)0number/100mlTreatment works
Escherichia coli (E.coli)0number/100mlConsumers’ taps