Regulation 4(9) and paragraph 3 of Part 1 of Schedule 3
| Anions | Unit of measurement |
|---|---|
| Borate BO3− | mg/1 |
| Carbonate CO32− | mg/1 |
| Chloride Cl− | mg/1 |
| Fluoride F− | mg/l |
| Hydrogen Carbonate HCO3− | mg/1 |
| Nitrate NO3− | mg/1 |
| Nitrite NO2− | mg/1 |
| Phosphate PO43− | mg/1 |
| Silicate SiO2 | mg/1 |
| Sulphate SO42− | mg/1 |
| Sulphide S2− | mg/1 |
| Cations | Unit of measurement |
| Aluminium A1 | mg/1 |
| Ammonium NH4+ | mg/1 |
| Calcium Ca | mg/1 |
| Magnesium Mg | mg/1 |
| Potassium K | mg/l |
| Sodium Na | mg/1 |
| Non-ionised compounds | Unit of measurement |
| Total organic carbon C | mg/1 |
| Free carbon dioxide CO2 | mg/1 |
| Silica SiO2 | mg/1 |
| Trace elements | Unit of measurement |
| Barium Ba | μg/l |
| Bromine (total) Br | μg/l |
| Cobalt Co | μg/l |
| Copper Cu | μg/l |
| Iodine (total) I | μg/l |
| Iron Fe | μg/l |
| Lithium Li | μg/l |
| Manganese Mn | μg/l |
| Molybdenum Mo | μg/l |
| Strontium Sr | μg/l |
| Zinc Zn | μg/1 |