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 |