Guideline values
There are a range of guidelines and regulations for drinking water quality operating at a worldwide down to country level. Below, we have collated values from The Private Water Supplies Regulations (England, Scotland and Wales), The European Union Drinking Water Directive and The World Health Organisation into an easily comparable table.
|
Parameter |
Unit of measurement |
Standards for private water supplies in england (2016) |
Standards for Private Water Supplies in Scotland (2006) |
Standards for Private Water Supplies in Wales (2017) |
World Health Organisation Standards (1993) |
European Union Drinking Water Directive (1998) |
|---|---|---|---|---|---|---|
|
Parameter |
Unit of measurement |
Standards for private water supplies in england (2016) |
Standards for Private Water Supplies in Scotland (2006) |
Standards for Private Water Supplies in Wales (2017) |
World Health Organisation Standards (1993) |
European Union Drinking Water Directive (1998) |
| Aesthetic parameters | ||||||
| Colour | mg/l Pt/Co | 20 | 20 | 20 | Acceptable to the consumer | Not mentioned |
| Odour | Dilution number | Acceptable to consumers and no abnormal change | 3 at 25ºC | Acceptable to consumers and no abnormal change | Acceptable to the consumer | Not mentioned |
| Taste | Dilution number | Acceptable to consumers and no abnormal change | 3 at 25ºC | Acceptable to consumers and no abnormal change | Acceptable to the consumer | Not mentioned |
| Turbidity | NTU (Nephelometric Turbidity Unit) | 4 | 4 | 4 | Acceptable to the consumer | Not mentioned |
| Microbiological parameters | ||||||
| Coliforms | number/ 100ml | 0 | 0 | 0 | Not mentioned | 0 |
| Colony Count at 22°C | number or cfu/ml | 100 (water in bottles or containers) | No abnormal change | No abnormal change | Not mentioned | 100 |
| Colony Count at 37°C | number or cfu/ml | 20 (water in bottles or containers) | Not mentioned | Not mentioned | Not mentioned | 20 |
| Clostridium | number/ 100ml | 0 | 0 | 0 | Not mentioned | 0 |
| E.Coli | number/ 100ml | 0 | 0 | 0 | Not mentioned | 0 |
| Enterococci | number/ 100ml | 0 | 0 | 0 | Not mentioned | 0 |
| Pseudonoma | number/ 250ml | 0 | 0 | 0 | Not mentioned | 0 |
| Chemical parameters | ||||||
| Acrylamide | μg/l | 0.10 | 0.10 | 0.10 | Not mentioned | 0.10 |
| Aluminium | μg/l | 200 | 200 | 200 | 200 | 200 |
| Ammonia | mg/l | Not mentioned | Not mentioned | Not mentioned | Not mentioned | 0.50 |
| Ammonium | mg/l | 0.50 | 0.50 | 0.50 | Not mentioned | Not mentioned |
| Antimony | μg/l | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Arsenic | μg/l | 10 | 10 | 10 | 10 | 10 |
| Benzene | μg/l | 1.0 | 1.0 | 1.0 | Not mentioned | 1.0 |
| Benzo(a)pyrene | μg/l | 0.010 | 0.010 | 0.010 | Not mentioned | 0.010 |
| Boron | mg/l | 1.0 | 1.0 | 1.0 | 0.3 | 1.0 |
| Bromate | μg/l | 10 | 10 | 10 | Not mentioned | 10 |
| Cadmium | μg/l | 5.0 | 5.0 | 5.0 | 3.0 | 5.0 |
| Calcium | mg/l | Not mentioned | Not mentioned | Not mentioned | No guideline | No guideline |
| Chloride | mg/l | 250 | 250 | 250 | 250 | 250 |
| Chromium | μg/l | 50 | 50 | 50 | 50 | 50 |
| Conductivity | μS/ cm at 20°C | 2500 | 2500 | 2500 | 2500 | 2500 |
| Copper | mg/l | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Cyanide | μg/l | 50 | 50 | 50 | 70 | 50 |
| 1,2 dicloroethane | μg/l | 3.0 | 3.0 | 3.0 | Not mentioned | 3.0 |
| Epichlorohydrin | μg/l | 0.10 | 0.10 | 0.10 | Not mentioned | 0.10 |
| Fluoride | mg/l | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 |
| Hydrogen ion (pH) | pH Value | 6.5 minimum to 9.5 maximum | 6.5 minimum to 9.5 maximum | 6.5 minimum to 9.5 maximum | No guideline | Not mentioned |
| Iron | μg/l | 200 | 200 | 200 | No guideline | 200 |
| Lead | μg/l | 10 | 10 | 10 | 10 | 10 |
| Manganese | μg/l | 50 | 50 | 50 | 500 | 500 |
| Magnesium | mg/l | Not mentioned | Not mentioned | Not mentioned | No guideline | No guideline |
| Mercury | μg/l | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Nickel | μg/l | 20 | 20 | 20 | 20 | 20 |
| Nitrate | mg/l | 50 | 50 | 50 | 50 | 50 |
| Nitrite | mg/l | 0.50 | 0.50 | 0.50 | 3 (as nitrite ion) | 0.50 |
| Polycyclic aromatic hydrocarbons (PAHs) | μg/l | 0.10 | 0.10 | 0.10 | Not mentioned | 0.10 |
| Selenium | μg/l | 10 | 10 | 10 | 10 | 10 |
| Silver | μg/l | Not mentioned | 10 | Not mentioned | No guideline | Not mentioned |
| Sodium | mg/l | 200 | 200 | 200 | 200 | 200 |
| Sulphate | mg/l | 250 | 250 | 250 | 500 | 250 |
| Tetrachloroethene and trichloroethene | μg/l | 10 | 10 | 10 | Not mentioned | 10 |
| Trihalomethanes: Total | μg/l | 100 | 100 | 100 | Not mentioned | 100 |
| Total dissolved solids (TDS) | mg/l | Not mentioned | Not mentioned | Not mentioned | No guideline | Not mentioned |
| Total organic carbon (TOCs) | mg/l | No abnormal change | No abnormal change | No abnormal change | Not mentioned | No abnormal change |
| Vinyl Chloride | μg/l | 0.50 | 0.50 | 0.50 | Not mentioned | 0.50 |
| Zinc | μg/l | Not mentioned | 5000 | Not mentioned | 3000 | Not mentioned |
| Pesticides | ||||||
| Aldrin | μg/l | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 |
| Dieldrin | μg/l | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 |
| Heptachlor | μg/l | 0.030 | 0.030 | 0.030 | No guideline | 0.030 |
| Heptachlor epoxide | μg/l | 0.030 | 0.030 | 0.030 | No guideline | 0.030 |
| Other pesticides | μg/l | 0.10 | 0.10 | 0.10 | Not mentioned | 0.10 |
| Pesticides total | μg/l | 0.50 | 0.50 | 0.50 | Not mentioned | 0.50 |