- Drinking Water 2024 – Summary of the Chief Inspector’s report for drinking water in England
- Foreword
- Water supplies and testing
- Compliance with water quality standards
- Water quality events
- Asset health and service reservoir integrity
- Consumer contacts
- Water safety planning and risk assessment
- Perfluoroalkyl and polyfluoroalkyl substances (PFAS)
- Audit programme completed by the Inspectorate
- Enforcement, transformation and recommendations
- Lead in water
- Materials in contact with drinking water (Regulation 31)
- Security and Emergencies (SEMD)
- Network Information systems (NIS)
- Research publications
- Raw water data
- Whistleblowers
- Working with stakeholders
- Annex A – Number of tests carried out by companies
- Annex B – Compliance with standards
- Annex C – Compliance failures and events
Annex B – Compliance with standards
Microbiological compliance at water treatment works
| Parameter | Standard | Total number of tests | Number of tests not meeting the standard | Number of tests not meeting the standard per company | Percent compliance (3dp) |
|---|---|---|---|---|---|
| Clostridium Perfringens (sulphite-reducing clostridia) (confirmed) | 0 number/100 ml | 24,840 | 8 | UUT(2) BRL(1) NES(2) TMS(1) SVT(2) | 99.968% |
| Turbidity – indicator | 1 NTU | 171,438 | 19 | UUT(1) TMS(3) NES(2) SWB(1) BRL(2) YKS(1) SVT(3) ANH(2) PRT(1) ISC(1) SST(1) SRN(1) | 99.898% |
| E. coli (confirmed) | 0 number/100 ml | 171,591 | 3 | ANH(1) SRN(1) TMS(1) | 99.998% |
| Total coliforms (confirmed) | 0 number/100 ml | 171,598 | 80 | SWB(2) SRN(6) ANH(11) YKS(12) SEW(2) UUT(3) TMS(6) PRT(1) ISC(2) CAM(1) NES(7) BRL(1) SVT(18) WSX(3) SST(5) | 99.953% |
| Total | 539,467 | 110 |
Microbiological compliance at service reservoirs
| Parameter | Standard | Total number of tests | Number of tests not meeting the standard | Number of tests not meeting the standard per company | Percent compliance |
|---|---|---|---|---|---|
| E. coli (confirmed) | 0 number/100 ml | 182,653 | 7 | YKS(2) NES(1) AFW(1) WSX(1) SST(1) ANH(1) | 99.996% |
| Total coliforms (confirmed) | 0 number/100 ml | 182,652 | 122 | SEW(5) TMS(8) YKS(30) SST(1) SVT(15) NES(8) CAM(3) UUT(13) AFW(8) SWB(8) BRL(3) WSX(8) ISC(2) SRN(1) ANH(9) | 99.935% |
| Total | 365,305 | 129 |
Microbiological compliance at consumers’ taps (water supply zones)
| Parameter | Standard | Total number of tests | Number of tests not meeting the standard | Number of tests not meeting the standard per company | Number due to consumer distribution systems | Percent compliance |
|---|---|---|---|---|---|---|
| Coliform bacteria (indicator) | 0 number/100 ml | 153,478 | 344 | ANH(19) YKS(43) UUT(56) CAM(1) IWN(8) SWB(9) NES(23) LNW(5) TMS(54) BRL(10) SST(6) ESP(3) AFW(11) WSX(5) SRN(9) SEW(17) ICW(2) PRT(1) SVT(62) | 193 | 99.776% |
| E. coli (confirmed) | 0 number/100 ml | 153,474 | 30 | SVT(4) ANH(1) YKS(3) NES(2) BRL(1) SST(1) SEW(1) TMS(10) AFW(3) UUT(4) | 19 | 99.980% |
| Enterococci (confirmed) | 0 number/100 ml | 13,376 | 8 | YKS(1) SWB(2) NES(2) LNW(1) AFW(1) ANH(1) | 3 | 99.940% |
| Total | 320,328 | 382 | 215 (56%) |
Detection of E. coli and Enterococci at treatment works, service reservoirs and consumers’ taps, by company
| Company | E. coli in water leaving treatment works | E. coli in water leaving service reservoirs | E. coli at consumers’ taps | Enterococci at consumers’ taps |
|---|---|---|---|---|
| AFW | 0 – 13,330 | 2 – 7,772 | 1 – 9,688 | 0 – 676 |
| ALB | 0 – 0 | 0 – 0 | 0 – 24 | 0 – 8 |
| ANH | 1 – 21,663 | 1 – 15,620 | 4 – 13,044 | 3 – 1,297 |
| BRL | 0 – 3,163 | 0 – 7,891 | 1 – 3,151 | 0 – 213 |
| CAM | 0 – 2,353 | 0 – 1,544 | 1 – 923 | 0 – 59 |
| ESP | 0 – 0 | 0 – 0 | 0 – 81 | 1 – 29 |
| ICW | 0 – 0 | 0 – 0 | 0 – 220 | 0 – 77 |
| ISC | 0 – 268 | 0 – 431 | 0 – 36 | 0 – 14 |
| IWN | 0 – 0 | 0 – 0 | 0 – 1,253 | 0 – 432 |
| LNW | 0 – 0 | 0 – 0 | 0 – 558 | 0 – 186 |
| NES | 0 – 9,943 | 0 – 15,027 | 1 – 11,688 | 1 – 896 |
| PRT | 0 – 3,313 | 0 – 1,437 | 1 – 1,906 | 0 – 118 |
| SES | 0 – 2,084 | 0 – 1,780 | 0 – 1,884 | 0 – 168 |
| SEW | 0 – 11,651 | 0 – 11,169 | 3 – 6,069 | 0 – 576 |
| SRN | 0 – 12,576 | 0 – 11,128 | 4 – 6,870 | 0 – 545 |
| SST | 0 – 4,291 | 0 – 1,608 | 0 – 3,483 | 1 – 224 |
| SVT | 1 – 22,683 | 0 – 21,836 | 3 – 22,132 | 1 – 1,676 |
| SWB | 0 – 8,225 | 0 – 13,803 | 1 – 6,080 | 4 – 481 |
| TMS | 0 – 17,808 | 0 – 19,222 | 10 – 26,031 | 2 – 2,006 |
| UUT | 0 – 16,546 | 0 – 17,815 | 1 – 19,532 | 0 – 1,877 |
| VWP | 0 – 156 | 0 – 306 | 0 – 48 | 0 – 8 |
| WSX | 1 – 8,799 | 0 – 16,244 | 0 – 3,753 | 0 – 522 |
| YKS | 1 – 14,019 | 2 – 17,567 | 4 – 13,427 | 1 – 712 |
| Total | 4 – 172,871 | 5 – 182,200 | 35 – 151,881 | 14 – 12,800 |
Chemical parameters
| Parameter name | Standard | Total number of tests | Tests not meeting the standard | Tests not meeting the standard per company |
|---|---|---|---|---|
| 1,2-Dichloroethane | 3 µg/L | 7,221 | 0 | |
| Benzene | 1 µg/L | 7,224 | 0 | |
| Pesticides (total by calculation) | 0.5 µg/L | 3,557 | 0 | |
| Trichloroethene & Tetrachloroethene – sum of 2 substances | 10 µg/L | 10,615 | 0 | |
| Tetrachloromethane | 3 µg/L | 10,639 | 0 | |
| Benzo[a]Pyrene (total) | 0.01 µg/L | 13,174 | 2 | TMS(1) IWN(1) |
| Polycyclic aromatic hydrocarbons (total by calculation) | 0.1 µg/L | 13,452 | 1 | TMS(1) |
| Trihalomethanes (total by calculation) | 100 µg/L | 13,474 | 0 | |
| Aluminium | 200 µg/L Al | 51,095 | 18 | NES(3) YKS(1) SRN(1) BRL(2) SST(1) UUT(7) AFW(3) |
| Arsenic | 10 µg/L As | 12,899 | 0 | |
| Bromate | 10 µg/L BrO₃ | 9,440 | 0 | |
| Cadmium | 5 µg/L Cd | 12,900 | 0 | |
| Cyanide | 50 µg/L CN | 3,128 | 0 | |
| Chromium | 50 µg/L Cr | 12,894 | 0 | |
| Iron | 200 µg/L Fe | 51,617 | 82 | SST(1) TMS(5) SRN(3) UUT(19) SEW(2) ANH(3) YKS(16) AFW(1) SWB(6) NES(10) WSX(1) BRL(2) SVT(13) |
| Mercury | 1 µg/L Hg | 3,157 | 0 | |
| Manganese | 50 µg/L Mn | 51,465 | 11 | SEW(1) YKS(2) NES(1) SVT(1) UUT(6) |
| Nickel | 20 µg/L Ni | 13,401 | 70 | IWN(5) YKS(3) SES(3) NES(3) TMS(6) SEW(4) AFW(2) LNW(2) SRN(8) BRL(4) UUT(5) ESP(11) WSX(1) ANH(2) SVT(11) |
| Lead | 10 µg/L Pb | 13,410 | 53 | SRN(2) YKS(4) UUT(8) BRL(1) WSX(1) AFW(2) NES(2) ANH(3) SVT(8) TMS(22) |
| Antimony | 5 µg/L Sb | 12,891 | 0 | |
| Selenium | 10 µg/L Se | 12,454 | 0 | |
| Electrical conductivity | 2500 µS/cm at 20°C | 47,540 | 0 | |
| Gross beta | 1 Bq/L | 749 | 0 | |
| Tritium | 100 Bq/L | 511 | 0 | |
| Gross alpha | 0.1 Bq/L | 750 | 13 | ANH(1) ESP(4) IWN(8) |
| Odour | Acceptable to consumers and no abnormal change | 56,028 | 68 | UUT(6) SVT(5) SEW(3) NES(16) SST(3) WSX(1) BRL(2) CAM(1) LNW(1) SRN(6) SWB(2) YKS(7) AFW(4) ANH(11) |
| Taste (quantitative) | Acceptable to consumers and no abnormal change | 55,887 | 55 | SRN(5) NES(12) ALB(1) YKS(12) SWB(1) UUT(5) ANH(5) AFW(1) ISC(3) SVT(3) WSX(3) BRL(3) IWN(1) PRT(1) |
| Residual disinfectant – free | 2 mg/L | 110,488 | 0 | |
| Residual disinfectant – total | 2 mg/L | 130,885 | 0 | |
| Boron | 1 mg/L B | 6,611 | 0 | |
| Copper | 2 mg/L Cu | 13,400 | 5 | SRN(1) AFW(1) BRL(1) TMS(2) |
| Fluoride | 1.5 mg/L F | 9,685 | 0 | |
| Sodium | 200 mg/L Na | 13,397 | 1 | AFW(1) |
| Ammonium (zone) | 0.5 mg/L NH₄ | 38,982 | 1 | TMS(1) |
| Nitrite – consumers taps | 0.5 mg/L NO₂ | 23,869 | 0 | |
| Nitrate | 50 mg/L NO₃ | 23,838 | 0 | |
| Colour | 20 mg/L Pt/Co | 55,498 | 0 | |
| Sulphate | 250 mg/L SO₄ | 7,117 | 0 | |
| Total indicative dose (gross alpha and beta) | 0.1 mSv/year | 75 | 0 | |
| Hydrogen ion (pH) – zone | 6.5 – 9.5 pH Value | 55,431 | 3 | UUT(1) ISC(1) SWB(1) |
| Total | 990,848 | 383 |
Pesticide parameters
| Parameter name | Standard | Total samples | Total failures | Detected pesticides |
|---|---|---|---|---|
| Individual Pesticides | 0.1 µg/L | 229,720 | 7 | Aldrin(1), Dieldrin(1), Propyzamide(3), Bentazone(2) |
| Total | 229,720 | 7 |
Pesticide failures
| Pesticide name | Standard | Total samples | Total failures | Comments |
|---|---|---|---|---|
| Aldrin | 0.1 µg/L | 3,732 | 1 | LNW(1) |
| Propyzamide | 0.1 µg/L | 5,128 | 3 | UUT(1) SVT(2) |
| Dieldrin | 0.1 µg/L | 4,329 | 1 | LNW(1) |
| Bentazone | 0.1 µg/L | 5,294 | 2 | TMS(2) |
| Total | 18,483 | 7 |