THE health of Bolton people was put at risk after a ‘failure of disinfection control’ at a United Utilities water treatment plant.

Almost 80,000 people had to boil their water for three days or United Utilities had to provide an alternative supply after a technical fault at Sweetloves treatment works in July last year.

The incident has been highlighted in the Drinking Water 2015 report by Marcus Rink, the Chief Inspector of Drinking Water, as a “major event”.

It emerged in the report that the company failed to learn lessons and there had been an issue concerning improperly disinfected water in March of last year. It was found then the company had failed to maintain equipment, there were inadequate disinfection treatment procedures in place.

Following the July incident, the company paid out hundreds of thousands of pounds in compensation to residents without water for 12 hours or more.

The company has been served with 12 ‘legal instruments’, including addressing disinfection issues at Sweetloves.

Mr Rink said in his report: “The overarching failure was that the risk assessment and subsequent mitigation or contingency planning was not evident. The company did not address the risks satisfactorily with the consequence that public health was put at risk when the systems failed. During the year, as the events were reported, there was clear indication that the company were not learning from previous errors.

“Disinfection is a fundamental tenet of water treatment and the failures that United Utilities displayed is wholly unacceptable.”

Raw water quality in the first incident was within normal ranges so no boil water advice was issued. In the second incident the company worked to restrict any ‘further improperly disinfected water entering supply’. The company later decided to release the water together with a boil water advice.

The report states: “This event provides a further example of companies failing to prevent inadequately treated and disinfected water entering supply from works and failing to control operational risks in the light of previous events and when the company is clear that the control is dependent upon critical equipment.

“It is questionable when the company strategy considers it acceptable not to put in robust maintenance for something as basic as sampling pumps compared to the senior decision and business risk necessary to recover from events of this size when considering a boil notice.”

The report highlighted the ‘inconsistent approach to issuing boiling water advice’ and stated that senior managers must be aware and be responsible for water quality and that risks are identified and that technology is “suitable and robust”.

Other incidents highlighted in the report include an incident in Kearsley when following a complaint the company found dangerously high levels of copper in the tap water.

United Utilities was criticised for the time taken to identify the root cause of the contamination, failure to carry out an urgent fittings inspection and failure to serve a legal Notice to ensure prompt rectification of the plumbing defects identified.

A spokesman for United Utilities said: “The water quality issue at Sweetloves happened in July, 2015.

“We paid compensation at the time and apologised to our customers for the inconvenience caused. Remedial action has either already been taken at the treatment works or is being planned and procedures and policies have changed to minimise the risk of any future incident.

“United Utilities is committed to maintaining a quality water supply through its network of 28,000 miles of mains pipes — enough to stretch around the world. Overall the DWI reports drinking water quality in the North continues to meet 99.96 per cent of regulatory standards.”

United Utilities refused to divulge what health risks the untreated water posed to members of the public.