Scotland’s drinking water continued to meet regulatory standards at a high rate during 2025, although performance at consumers’ taps fell slightly from the previous year and complaints to Scottish Water increased.
The Drinking Water Quality Regulator for Scotland reported that 137,947 regulatory tests were carried out on samples taken from consumers’ taps during 2025. Of those tests, 99.88 per cent met the required standards.
In 2024, 156,814 regulatory tests were carried out at consumers’ taps and 99.92 per cent met the required standards. In 2023, compliance at consumers’ taps was also recorded at 99.88 per cent.
At water treatment works, 22 out of 62,134 tests on samples of water leaving works failed to meet standards in 2025. The Scottish Government said that figure was comparable with recent years.
The regulator also recorded 36 water-quality incidents requiring detailed investigation during 2025, compared with 34 in the previous year. The regulator described the 2025 figure as too high.
Scottish Water received 17,558 complaints from consumers about drinking-water quality during 2025, a five per cent increase on 2024. Most complaints concerned discoloured water.
The Drinking Water Quality Regulator said consumers expect tap water to look, taste and smell good, and that incidents of discoloured water continue to affect some customers. The regulator linked action on the issue to maintaining public trust and confidence in Scotland’s drinking-water supplies.
The Public Water Structure Created After Devolution
Scotland’s present public water structure dates from the early years of devolution.
The Water Industry (Scotland) Act 2002 set up Scottish Water, the Drinking Water Quality Regulator and Customer Consultation Panels. Scottish Water became the public corporation responsible for public drinking-water and sewerage services, taking over from the previous regional water authorities.
The Drinking Water Quality Regulator was created at the same time. It is independent of Scottish Ministers and is responsible for ensuring that Scottish Water complies with its drinking-water quality duties. It reviews water-quality data from samples taken by Scottish Water, carries out targeted audits, and supervises local-authority enforcement of the private water-supply regulations.
The regulator also reports annually on drinking-water quality. The 2025 report is the 24th annual report.
The Water Services etc. (Scotland) Act 2005 then strengthened economic regulation, introduced the Water Industry Commission for Scotland, and introduced retail competition for non-domestic customers.
The resulting structure kept Scottish Water in public ownership while opening non-household retail services to licensed providers in a competitive market.
Public Water And Private Supplies
The Scottish Government describes Scottish Water as the public company providing Scotland’s public drinking-water and sewerage services. Private water supplies remain the responsibility of owners and users and are regulated by local authorities.
The annual public-water report describes performance across Scottish Water’s public supply. It does not mean that every household, farm, croft, rural business or settlement is connected to the public network.
The consultation material for the next water-services period states that Scottish Water supplies clean water to 97 per cent of households and businesses in Scotland and provides wastewater services to 93 per cent.
That leaves a minority outside the public-supply system for either water, wastewater or both. For those users, the public-water model is not the whole practical experience of water access, treatment, testing, maintenance and repair.
The Charging Review Now Under Way
The 2025 drinking-water figures have been published during the same period as the next strategic review of water charges.
The Scottish Government has published analysis of responses to its consultation on water services from 2027. The consultation covered ministerial objectives and charging principles for the 2027 to 2033 regulatory period.
The consultation was open from 6 January to 30 March 2026 and received 58 responses, including 21 from individuals and 37 from organisations.
Seven in ten respondents who answered the relevant question agreed that the ministerial objectives identified the type of investment activity Scottish Water should undertake between 2027 and 2033. The analysis recorded support for investment in infrastructure and for the draft objectives. It also recorded calls for improved accountability and monitoring, stronger climate resilience, and balancing affordability of charges.
Respondents most frequently identified safe, reliable and accessible water and wastewater services, environmental protection, and public ownership as aspects they valued. When asked about concerns, the most commonly mentioned issues were affordability, ageing infrastructure and climate change.
On charging, 42 per cent of those answering agreed that the draft principles of charging remained appropriate for 2027 to 2033. Thirty-five per cent were neutral and 24 per cent disagreed. The Scottish Government’s analysis said themes in open comments included support for the proposed approach, concern about the continued use of council-tax bands to determine charges, and affordability.
Scottish Water’s operations, including service maintenance and improvement, are mostly financed by customer charges. Household charges are collected alongside council tax. Business customers pay through licensed providers in the retail market.
WICS Draft Determination
The Water Industry Commission for Scotland published its draft determination for 2027 to 2033 on 30 June 2026.
The draft determination sets out WICS’s draft decision on the maximum amount Scottish Water can charge customers during the period. WICS said the draft decision supports £7.9 billion of investment while capping charge increases at CPI plus two per cent. The draft decision also includes the possibility of an additional conditional allowance of up to 0.3 per cent in the final three years where evidence justifies costs outside Scottish Water’s control, including energy.
Scottish Water had proposed charges increasing by CPI plus 21.5 per cent by 2033. WICS’s draft decision set a lower charge path of up to CPI plus 13.6 per cent by 2033.
WICS also reduced Scottish Water’s proposed £8.1 billion investment programme to £7.9 billion after challenge, set a £216 million cost challenge over the period, and added conditions before customers pay for major project costs that remain uncertain.
The draft decision includes proposed investment of £1.118 billion to deliver water quality and resilient water supplies, £1.284 billion to reduce pollution, improve wastewater treatment and protect rivers, coasts and the wider environment, and £4.926 billion to renew pipes, mains and treatment works.
The regulator also set out performance expectations. These include saving 67 million litres of water currently lost through leaks each day by 2032-33, reducing serious pollution incidents from Scottish Water’s forecast of eight in 2026-27 to four in 2032-33, and reducing sewer flooding in homes from a forecast of 421 houses in 2026-27 to 342 in 2032-33.
For drinking-water quality, Scottish Water proposed 99.95 per cent compliance by the end of the regulatory period. WICS’s draft decision set an enhanced target of 99.97 per cent compliance.
What The 2025 Figures Add To The Record
The 2025 drinking-water figures add another dated entry to the record of Scotland’s public water system.
They show continued high compliance with drinking-water standards at consumers’ taps. They also show slightly lower tap-sample compliance than 2024, more complaints about drinking-water quality, and a small increase in water-quality incidents requiring detailed investigation.
The figures do not show a public-water system failing its regulatory standards. They show a system with high measured compliance and continuing operational issues visible to consumers, particularly through discoloured water.
The wider public record now contains three connected elements.
The first is the annual quality record, which measures drinking-water performance during 2025.
The second is the charging and investment review for 2027 to 2033, which will determine the financial framework for Scottish Water’s next period of operation.
The third is the public-water structure created after devolution, in which Scottish Water, the Drinking Water Quality Regulator and WICS occupy separate roles inside a publicly owned water model.
Scotland’s water system is being assessed on more than one timescale. The annual report records what happened in 2025. The strategic review sets the financial limits for 2027 to 2033. The structure itself comes from the settlement made in 2002 and amended by later legislation.
The tap-water figures are part of that longer public record.
Sources
Drinking Water in Scotland 2025, 27 August 2026
https://www.gov.scot/news/drinking-water-in-scotland-2025/
Scottish Water Responds to DWQR Annual Report on Drinking Water Quality, 27 August 2026
https://www.scottishwater.co.uk/about-us/news-and-views/2026/08/270826-response-to-dwqr-annual-report
Drinking Water in Scotland 2024, 10 September 2025
https://www.gov.scot/news/drinking-water-in-scotland-2024/
Drinking water in Scotland 2023, 20 August 2024
https://www.gov.scot/news/drinking-water-in-scotland-2023/
Water services: investing in and paying from 2027 — Analysis of Consultation Responses, 27 August 2026
https://www.gov.scot/publications/water-services-investing-paying-2027-analysis-consultation-responses/
Water services: investing in and paying from 2027 — Consultation on Ministerial Objectives, 27 August 2026
https://www.gov.scot/publications/water-services-investing-paying-2027-analysis-consultation-responses/pages/3/
Water services: investing in and paying from 2027 — Consultation on the Principles of Charging, 27 August 2026
https://www.gov.scot/publications/water-services-investing-paying-2027-analysis-consultation-responses/pages/4/
Water services — investing in and paying from 2027: consultation, 6 January 2026
https://www.gov.scot/publications/water-services-investing-paying-2027/
Water services: investing in and paying from 2027 — Scottish Government consultation page, 6 January 2026
https://consult.gov.scot/energy-and-climate-change-directorate/water-services-investing-paying-2027/consult_view/
2027-33 Draft Determination, 30 June 2026
https://wics.scot/publications/price-setting/strategic-review-charges-2027-33/determinations/2027-33-draft-determination
2027-33 Draft Determination — Our draft decision, 30 June 2026
https://wics.scot/publications/price-setting/strategic-review-charges-2027-33/determinations/2027-33-draft-determination/our-draft-decision
2027-33 Draft Determination Consultation, 30 June 2026
https://www.wics.scot/consultations/price-setting-consultations/2027-33-draft-determination-consultation
WICS publishes 2027-33 Draft Determination, 30 June 2026
https://www.wics.scot/latest/wics-publishes-2027-33-draft-determination
Water industry: legislation, updated 2026
https://www.gov.scot/publications/water-industry-legislation/
Water — Scottish Government policy, accessed 27 August 2026
https://www.gov.scot/policies/water/
