- Drinking Water 2025 – Summary of the Chief Inspector’s report for drinking water in Wales
- Foreword
- Introduction
- Water supplies and testing
- Compliance with standards
- Learning from compliance failures
- Learning from events
- Consumer contacts
- Asset health
- Water safety planning and risk assessment
- Poly and perfluoroalkyl substances (PFAS)
- Audit programme
- Recommendations
- Enforcement
- Security and Emergency Measures Direction - SEMD
- Network and Information Systems - NIS
- Materials in contact with drinking water (Regulation 31)
- Research publications
- Whistleblowers
- Working with stakeholders
Consumer contacts
Acceptability of water
The acceptability of drinking water is consistently ranked by consumers as a high priority. It can be affected by several factors, including appearance, such as discolouration or aeration, and taste or odour. Most acceptability complaints relating to black, brown or orange discolouration are associated with raised concentrations of manganese, iron and aluminium.
Although these metals are rarely present at concentrations harmful to health, they can cause widespread rejection of water on the basis of appearance. Consumers expect their drinking water to be clean and safe, and discolouration events can be highly disruptive and reduce confidence in supply. The Inspectorate takes these events seriously and many companies have regulation 28(4) notices in place to address the root causes of discolouration. In February 2024, the Inspectorate issued Information Letter 01/2024, Annual Provision of Information on Consumer Contacts, which set out new requirements for companies to report more detailed consumer contact information, including:
- A unique reference for each contact;
- Details of the district metered area the contact is located in;
- The date and time of the contact;
- The national grid reference (easting and northing) of the location of the contact;
- The mode of contact;
- Whether the contact is a repeat within a 12-month rolling period (that is a new occurrence or ‘case’ of a similar issue from the same consumer);
- and if the contact is associated with a notifiable event, and the event reference number associated with it.
Information regarding multiple contacts, for example if a consumer reports more than one drinking water quality concern during a contact, is also recorded.
The data submitted by companies in 2025, covering 2024, was the first submission to include this additional information. Direct year-on-year comparisons for the new data are therefore not yet possible. To maintain continuity of a comparable dataset and monitor industry performance and progress, only primary contacts and non-event contacts have been used in reporting acceptability data for 2024. When a meaningful dataset is available, further analysis will be undertaken to provide additional insight into consumer contacts.
In Wales in 2025, there were 8,161 consumer contacts regarding the appearance, taste and odour of drinking water, reported to companies wholly or mainly operating in Wales. This equates to a rate of 2.46 contacts per 1,000 population. Table 8 shows the number of contacts received for each complaint type for Welsh companies, with contacts relating to discoloured water, including brown, orange and black water, being the most common reason.
| Category | Number of contacts | Wales contact rate per 1000 population | Industry contact rate per 1000 population |
|---|---|---|---|
| Appearance – Brown Black Orange | 5,149 | 2.46 | |
| Taste / Odour – Other | 894 | ||
| Appearance – White Air | 676 | ||
| Drinking water quality concern – Lead and analysis | 503 | ||
| Taste / Odour – Chlorine | 501 | ||
| Appearance – Particles | 340 | ||
| Illness – Gastroenteritis | 339 | ||
| Appearance – General Conditions | 204 | ||
| Appearance – White Chalk | 147 | ||
| Taste Odour – Earthy Musty | 132 | ||
| Illness – Skin | 102 | ||
| Appearance – Blue Green | 64 | ||
| Illness – Oral | 38 | ||
| Taste / Odour – Petrol Diesel | 37 | ||
| Illness – Medical Opinion | 23 | ||
| DWQ Concern – Incident Related | 20 | ||
| Appearance – Animalcules | 17 | ||
| Drinking water quality concern – Lifestyle | 5 | ||
| Drinking water quality concern – Pets Animals | 4 | ||
| Drinking water quality concern – Campaign | 0 | ||
| Total | 9,195 |
Table 11. Water quality complaints in Wales, 2025
Discoloured water
The Inspectorate reviews consumer contact data for discoloured water contacts on an annual basis. Companies whose performance is poorer than the industry average are investigated, and enforcement action taken where necessary. Dŵr Cymru Welsh Water has had a company-wide notice in place since 2022, with six individual zonal notices remaining from AMP7. Companywide discolouration performance is considered when serving notices, in addition to individual water supply zone performance. When completed, these legal instruments will improve water quality to consumers supplied in these areas.
The number of contacts reporting discoloured water, including brown, orange or black water, across the industry in England and Wales has decreased over recent years. This improvement now appears to have stalled, with deterioration reported in 2024, when the rate was 0.49 contacts per 1,000 population, and almost no improvement in 2025, when the rate was 0.48. This equates to 29,959 contacts across the industry in 2025 regarding black, brown and orange water. In Wales, this stagnation is also apparent, with a notable deterioration in 2024 and no sustained improvement over the past five years. The rate in Wales was 1.55 contacts per 1,000 population in 2025.
Figure 30 – Welsh company and industry discolouration rates 2016 to 2025
The 2025 rate of 1.55 contacts per 1,000 population in Wales is significantly higher than the industry average of 0.48. Of the Welsh contacts, 98.3% were from consumers served by Dŵr Cymru Welsh Water. The company remains the worst performing company in the industry for discolouration and has held this rank since 2014, as shown in Figure 31.
Figure 31 – Rate of discolouration contacts by company in 2025 (excluding Isles of Scilly and inset companies)
The contact rate for Hafren Dyfrdwy, which had been showing an improvement, has stalled in recent years (Figure 32). The company’s rate remains under the industry average.
Figure 32 – Welsh company and industry discolouration rates 2016 to 2025
Figure 31 shows where the Welsh companies rank over the whole industry for discolouration contact performance in 2025.
Dŵr Cymru Welsh Water remain an industry outlier and although the deterioration in 2024 was improved upon in 2025, there has been no overall improvement in rate in the past five years. Dŵr Cymru Welsh Water had a number of zone-specific discolouration notices and a companywide notice for discolouration. Three of the zone-specific notices have been delayed into AMP8. The companywide notice was served in 2022 with a target of 1.4 contacts per 1,000 population to be achieved by the end of AMP7. Figure 33 shows that the company fell short of this target. When there was an early indication that this target would not be met, the Inspectorate engaged with the company to better understand why the company believed this was the case by critically evaluating how the company determined its deliverables and the resulting impact. Part of this ongoing notice included setting a new target for the end of AMP8 using the same methodology as that for the AMP7 target. The company’s new target is 1.08 contacts per 1,000 population.
Figure 33 – Welsh company and industry discolouration rates 2016 to 2025
Dŵr Cymru Welsh Water remains an industry outlier for discolouration. Although performance improved from the deterioration seen in 2024, there has been no overall improvement in the contact rate over the past five years. The company has a number of zone-specific discolouration notices and a company-wide notice for discolouration. Three of the zone-specific notices have been delayed into AMP8. The company-wide notice was served in 2022 with a target of 1.4 contacts per 1,000 population to be achieved by the end of AMP7. Figure 15 shows that the company did not meet this target. Following early indications that the target would not be achieved, the Inspectorate engaged with the company to understand the reasons, including how deliverables had been determined and what impact they were expected to have. A new AMP8 target has been set using the same methodology as the AMP7 target. The company’s new target is 1.08 contacts per 1,000 population.
In addition to the overall black, brown and orange contact rates described above, several consumer complaints received by the Inspectorate in 2025 were prompted by persistent and unresolved discolouration of supply. To assess the impact of ongoing discolouration on consumer confidence, three cases reported in the Dŵr Cymru Welsh Water area in 2025 are considered below. Taken together, these cases highlight persistent challenges in managing discolouration, maintaining consumer confidence, and delivering effective investigative and operational responses.
Across all cases, consumers reported ongoing aesthetic water quality issues, primarily discolouration and, in some instances, odour, leading to rejection of supply. While the company implemented a range of mitigation measures, the Inspectorate consistently identified shortcomings in investigation quality, sampling adequacy, and response timeliness.
Overall, the findings point to systemic pressures within the industry, particularly in relation to ageing assets, network management practices, and complaint handling processes. Regulatory conclusions emphasise the need for more proactive, evidence-based, and customer-focused approaches to both investigation and resolution.
One case involved long-term, intermittent discolouration affecting a localised supply area, with repeated consumer contacts over several years. Mitigation measures included reactive turnover flushing, the introduction of a routine flushing programme, and installation of an inline supply filter. However, investigative activity remained limited, with only a small number of samples taken despite the persistence of issues.
Although sample results demonstrated compliance with regulatory standards at the time of testing, the continued presence of visible discolouration meant the supply remained unacceptable to the consumer. The Inspectorate concluded that the measures taken had not addressed the underlying cause or provided sufficient reassurance.
A second case concerned a long-running complaint in an urban network involving both discolouration and odour, with initial contacts dating back several years. Early investigative activity was limited, and opportunities to undertake timely sampling and identify root causes were missed. A more comprehensive investigation was only initiated following later water quality failures identified during the water quality zone’s routine compliance sampling process, at which point elevated iron concentrations were identified.
The underlying cause was attributed to ageing infrastructure and low network turnover, which contributed to sediment mobilisation and aesthetic failures. Although mitigation measures, including enhanced flushing and monitoring, were eventually implemented, delays and investigative deficiencies prolonged the impact on consumers.
The third case involved a multi-year group complaint affecting several properties in a rural network. Consumers reported persistent discolouration alongside pressure and supply issues over an extended period. Sampling confirmed elevated iron and turbidity, while the network itself was characterised by ageing iron mains in poor condition with significant sediment accumulation.
A range of operational interventions, such as flushing programmes, supply rezoning, and installation of point-of-use filters, were implemented. However, these measures did not deliver sustained improvement, highlighting the limitations of short-term mitigation in the absence of fundamental infrastructure renewal.
Across all cases, the condition of distribution assets, particularly ageing iron mains, was identified as a primary driver of discolouration (figure 34). Low flow conditions and hydraulic disturbances were found to mobilise accumulated sediments, resulting in recurring water quality failures. These issues were especially acute in network extremities and areas with limited turnover.
The Inspectorate also identified consistent deficiencies in investigation and sampling practices. Sampling was frequently delayed, insufficient, or not representative of actual conditions. Repeat complaints did not consistently trigger escalation or enhanced investigation, and opportunities for early intervention were missed, allowing issues to persist over extended periods.
Operational mitigation measures, such as flushing and point-of-use filters, were widely used but provided only temporary mitigation. Flushing improved water clarity in the short term (Image x) but did not prevent recurrence, while filters addressed symptoms at individual properties rather than systemic causes. In some cases, flushing activities themselves risked worsening conditions by mobilising accumulated sediments.
Communication with consumers emerged as another critical area for improvement. Delays in providing updates and test results reduced consumer confidence, while explanations of root causes and mitigation measures were sometimes incomplete or inconsistent. As a result, consumers remained unconvinced of the safety or reliability of the supply despite regulatory compliance in many instances.
These cases reinforce regulatory expectations that water companies must undertake timely and representative sampling, apply risk-based investigation methods that consider upstream network factors, and implement robust systems to identify and escalate repeat complaints. Failure to meet these expectations is likely to result in increased regulatory scrutiny.
The repeated identification of infrastructure condition as a root cause highlights the need for accelerated asset investment. Targeted mains replacement in high-risk areas, improved management of network extremities, and better integration of asset condition data into water quality planning are all necessary to achieve sustained improvements. In several cases, infrastructure renewal has been identified as the only effective long-term solution.
More broadly, the findings reflect wider industry performance pressures. Elevated discolouration complaint rates and ongoing regulatory interventions indicate that systemic improvements are required. There is growing expectation that companies demonstrate measurable progress in both operational performance and customer outcomes.
The complaint assessments outlined above reveal consistent patterns of operational and structural challenge in maintaining water quality within distribution networks. While steps have been taken to address individual issues, responses have often been reactive and insufficient to resolve underlying causes. Persistent discolouration, combined with delayed or inadequate investigation, has led to prolonged consumer dissatisfaction and reduced confidence in supply.
The Inspectorate’s findings point to the need for a step-change across the industry. This includes more rigorous and timely investigations, effective escalation of repeat complaints, improved transparency in consumer communication, and sustained investment in infrastructure to address root causes.
Taken together, these cases demonstrate the importance of moving from reactive discolouration management towards proactive, system-wide improvement in both technical performance and customer assurance.
Taste and odour
As with discoloured water contacts, the industry rate for total taste and odour contacts has gradually reduced over time, although it worsened in 2024 and 2025 to 0.27 contacts per 1,000 population. In Wales, the rate was almost double the industry rate, at 0.47 contacts per 1,000 population in 2025, and has remained broadly stable, with no sustained progress over the last decade.
Figure 36 – Rate of taste and odour contacts in Wales
Earlier in this report, examples of investigations into taste and odour compliance failures were described. These instances do not necessarily result in, or directly correlate with, consumers contacting their water company. Consumer contact data therefore provides a useful reflection of direct consumer experience and offers an alternative insight to that provided by compliance failures. General taste and odour, and chlorine-related contacts, feature prominently across the years shown in Figure 36. While it is not realistic to expect all consumer contacts to be eliminated, the lower industry rate in England, including companies with similar source and network characteristics, indicates that further mitigation of the causes of these contacts is achievable.