Northumbrian Water has been fined £499,725 after pleading guilty to the supply of water “unfit for human consumption”.

At Peterlee Magistrate’s Court on 10 January, the company was ordered to pay the fine and costs of £32,792.65, which were agreed out of court. A victim’s surcharge of £170 was applied.

The Drinking Water Inspectorate (DWI) which brought the charges against the water company accused Northumbrian Water of “cutting corners”.

Northumbrian Water pleaded guilty to the supply of water unfit for human consumption and for an offence arising from not following the manufacturer’s instruction for use of a product.

The offences arose between 15 December 2016 and 20 December 2016 when water with a taste and odour was supplied from South Moor Service Reservoir, located in Burnhope, Durham which serves 10,000 consumers in County Durham.

The event followed maintenance work on the reservoir that required the internal application and curing of an epoxy coating material. The curing period was not as required in the instructions for use and, when the reservoir was returned to supply, caused taste and odour issues for consumers. Consumers described the water as tasting like medicine, plastic, chemical or metallic.

The DWI was critical of the “lack of supervision and control” of those carrying out the work and the lack of adequate checks on water quality prior to returning the reservoir to service.

The charges were brought under Section 70 of the Water Industry Act 1991 (as amended) and Regulation 33(3)(b).

Marcus Rink, chief inspector of Drinking Water, said: “This was an event that should not have happened. Corners were cut in carrying out the work and inadequate scrutiny did not identify this.

“Consumers experienced water with an unpleasant taste and odour which is likely to have been detected had adequate checks been carried out before the reservoir was put back into service.

“This prosecution acts as a reminder to companies of their ultimate responsibility for drinking water quality at all times. We are content that the court has recognised the seriousness of this event.”

Ceri Jones, assets and assurance director at Northumbrian Water, said: “We are very sorry for what has happened and would like to apologise to the people who were affected by this incident.

“It is important to stress that whilst a small number of customers did experience an unpleasant taste and odour with the water supplied, there was never a risk to health to anyone as a result of this incident.

“Northumbrian Water was unaware of the decision to remove equipment or reduce costs during the maintenance work, this decision was taken by a third-party contractor and we would not have agreed to it if asked.

“As a company we pride ourselves on providing great quality drinking water for our customers and it’s only right that the DWI hold us to account when these standards slip.”

He added: “As soon as we became aware of customers’ concerns we acted to put this right and ensure our normal very high standards were restored.

“We have learned valuable lessons from the incident, which happened in 2016 and have carried out a full and comprehensive review of our procedures and processes and implemented our learnings from it.

“No similar incidents have occurred since and our learnings have been shared with other water companies with best practice guidelines that have been developed to ensure something like this does not happen again.”

The DWI checks that water companies in England and Wales supply drinking water that does not put consumers at risk, and that is wholesome and acceptable. It is a criminal offence for a water company to supply water that is unfit for human consumption.