Regulation 9
Note: This table sets out the annual sampling frequencies for all the substances and parameters in column 1. These are determined for each water supply zone according to its estimated population (column 2). The number of samples is either the standard number in column 4 or the reduced number in column 3 (if one is given). Regulation 9 provides for the circumstances in which the reduced number of samples may be taken.
(1) Substances and parameters subject to monitoring | (2) Estimated population of water supply zone | (3) Reduced | (4) Standard |
|---|---|---|---|
(*) Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below. | |||
(i) Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000. | |||
(ii) Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required. | |||
(iii) Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points. | |||
(iv) To monitor for total indicative dose (for radioactivity).” | |||
| Subject to check monitoring | |||
| E. coli | < 100 ≥ 100 | 4 12 per 5,000 population(i) | |
| Coliform bacteria | |||
| Residual disinfectant | |||
| Aluminium | <100 100–4,999 5,000–9,999 10,000–29,999 30,000–49,999 50,000–79,999 80,000–100,000 | 1 2 6 12 18 26 38 | 2 4 12 24 36 52 76 |
| Ammonium | |||
| Clostridium perfringens (including spores)(*) | |||
| Colony counts | |||
| Colour | |||
| Conductivity(*) | |||
| Hydrogen ion | |||
| Iron | |||
| Manganese | |||
| Nitrate(ii) | |||
| Nitrite(ii) | |||
| Odour | |||
| Taste | |||
| Turbidity | |||
| Subject to audit monitoring | |||
| Aluminium | <100 100–4,999 5,000–100,000 | 1 4 8 | |
| Antimony | |||
| Arsenic | |||
| Benzene(*) | |||
| Benzo(a)pyrene | |||
| Boron(*) | |||
| Bromate(iii) | |||
| Cadmium | |||
| Chromium | |||
| Clostridium perfringens (including spores) | |||
| Copper | |||
| Cyanide(*) | |||
| 1,2 dichloroethane(*) | |||
| Enterococci | |||
| Fluoride(*) | |||
| Iron | |||
| Lead | |||
| Manganese | |||
| Mercury(*) | |||
| Nickel | |||
| Nitrate(ii) | |||
| Nitrite(ii) | |||
Pesticides and related products(*) | |||
| Polycyclic aromatic hydrocarbons | |||
| Selenium | |||
| Sodium | |||
| Trichloroethene/ | |||
| Tetrachloroethene(*) | |||
| Tetrachloromethane(*) | |||
| Trihalomethanes | |||
| Chloride(*) | |||
| Sulphate(*) | |||
| Total organic carbon(*) | |||
| Tritium(*) | |||
| Gross alpha(*) (iv) | |||
| Gross beta(*) (iv) | |||