The water companies in England collectively carried out a total of 3,502,637 drinking water quality tests during 2019 - only 1,509 of the tests failed to meet one or more of the standards set down in the regulations or exceeded a screening value.

Throughout 2019, water companies sampled drinking water across England to verify compliance with the drinking water regulations, according to the newly published 30th Annual Report by the Drinking Water Inspectorate (DWI).

The report, which covers public water supplies, says that almost half of the tests were carried out on samples drawn from consumers’ taps selected at random.

Drinking water 2019 provides a record of the work of the Inspectorate in checking that water companies have taken the appropriate action to maintain confidence in drinking water quality and to safeguard public health.

Lead will ontinue to be potential risk to mental and physical health of future generations, until lead piping is removed from domestic plumbing

The report states:

“The status of water quality in England is at a very high standard but work remains to improve planning for future generations: It is difficult to escape the question of lead.”

According to the report, fifty years after the use of lead pipes were made illegal the industry has not made significant progress, largely because ownership of supply pipes from the property curtilage remains with the householder.

The most significant risk of lead dissolving into the water is from where it sits in the last few meters of piping waiting to be drawn from the tap. As a result, this will continue to be a potential risk to the mental and physical health of future generations , until lead piping is removed from domestic plumbing.

The DWI also draws attention to the fact that global challenges such as CoViD-19, coupled with current water resource demand and availability, pose “challenges for the maintenance of supply during these difficult times.”

Referring to the fact that companies in England have identified “no supply” as being a key risk., the report says:

“Demand and resource all threaten water quality and sufficiency for which long term planning will be vital to maintain both our industry and our private supplies. We have clear evidence that water resource challenges result in water quality failings and the decision between sufficiency and quality is not a choice that can be or should have to be made.”

In England, compliance failures and unplanned events are dominated by microbiological parameters such as coliforms, E. coli and low-level Cryptosporidium detections, compounded by repeated turbidity failures at treatment works.

The report warns that changing patterns of the weather can play a role with increased numbers of failures during heavy rain, commenting:

“Asset condition is a significant contributing risk since poor condition or structural defects permit ingress. Any manifestation of this risk could have serious consequences.”

Referring to the requirement for the water companies to provide risk assessments, the report says in 2019, of approximately 1.5 million hazards, analysis indicated 94% of the risks are being effectively mitigated.

The DWI concludes that this “illustrates the high standards companies hold themselves to in securing good clean drinking water.”

‘No supply’ and microbiological risks are the top two identified risks, while the remaining risks, identified within company risk assessments, are grouped as domestic plumbing related and fall into two groups, metals and taste/odour.

The report provides a summary of 3,502,637 compliance results taken by the industry, and the associated investigations taken for 1,433 failures of regulatory standards.

The continuing performance by the industry is measured by the Compliance Risk Index (CRI), designed to allocate a numerical value to risk. For 2019, the CRI for England was 2.80 compared to the wider industry value of 2.87. A lower value indicates a lower risk.

Four companies will be subject to further scrutiny

From 2020 companies have a target to achieve an individual CRI of 2 as a common performance commitment. The median value for 2019 is 1.73 and so over half of companies are now meeting this expectation.

However, the report points out that Southern Water are “notable with a score of 7.66 which is over 4 times the current median value and of which 69% was due to coliforms at treatment works.” All the failures were investigated and actions carried out to protect consumers.

The performance of the industry is measured by the Event Risk Index (ERI) - a lower value indicates a lower risk. In 2019 the ERI for England was 723. A performance target of 30 would be considered acceptable. Over half of companies achieve this standard but “of particular note” are four companies in England: Northumbrian Water, United Utilities Water, Southern Water and Thames Water who were above the national ERI.

The report also highlights Northumbrian Water as “notably over 2.5 times the value of the next highest company” - due largely to an unplanned event at its Whittle Dene works where Cryptosporidium was detected.

The DWI said that all four companies will be subject to further scrutiny.

The Inspectorate completed two prosecutions in 2019 - one at South Moor, operated by Northumbrian Water, recorded the largest fine ever for a Water Quality prosecution at just under £500,000. The second was at Coppermills, a key works supplying north east London, where four charges were brought against Thames Water.

Management continues to be the biggest contributory area to recommendations made by DWI

The Inspectorate issued 577 formal recommendations during 2019 to water companies in England and Wales, in response to an actual breach, or a risk of a breaching, the regulations. The mean recommendation score for the companies in England as a whole declined, following 2 consecutive years of increases. However, the DWI concludes:

“It is uncertain whether this slight decrease will revert the increasing trend of recent years,”

The report says that management continues to be the biggest contributory area to recommendations across the industry - made up of areas including risk assessment, policy/procedure, operation, maintenance, staff issues and investigation. “Of these, the consistently largest contributor is poor risk assessment,” it says.

The DWI concludes:

“Risk assessment deficiencies remain a perennial issue, as are recommendations linked to disinfection. Both of these areas are core to producing safe water and must be right first time in the assurance of water arriving at the tap. Drinking water cannot be recalled and so assessment, mitigation and control has to prevent failure before it happens. Equally disinfection is the last barrier and cannot be compromised ever.”

The report draws particular attention to United Utilities, saying that it continued to receive significantly more recommendations than the industry average, with a slight increase in recommendations made in 2019, compared to 2018.

The DWI said:

“Management deficiencies contributed the highest number of recommendations for this company and this presents an unnecessary risk.

“The Company should urgently investigate the sources of recommendations and consider how the number of recommendations can be reduced or resolved.”

“No supply “ is top water industry hazard

The highest scoring hazard across the English water comp anies was ‘no supply’ – the hazard attracts a high multiplier because of the potential contamination associated with depressurisation and because of the effect on vulnerable consumers, services and businesses.

The DWI concludes that any schemes relating to resilience and security of supply are likely to become more critical in future years. The report recommends that the water companies should review their risks associated with no supply and ensure they remain on track and are delivered more expeditiously where possible.

Click here to download the DWI report in full