United Utilities (UU) has fully lifted the boil water notice across Lancashire, a month after it was first issued to more than 300,000 customers following traces of cryptosporidium being found at a water treatment works.

The staged lifting of the restrictions was finally completed on Sunday evening when UU removed the restrictions for the final customers who have had to boil their tap water since 6 August.

UU confirmed that through the combination of installing ultraviolet dosing rigs and flushing the network, water supplies are now back to normal and the last traces of the parasite have been removed.

Compensation payouts, which are expected to cost UU at least £15 million, have started being sent to customers affected by the boil water notice, with the average settlement ranging from £50 to £60, depending on when the boil water notice was lifted.

Further claims are expected when businesses customers begin appealing for additional compensation as a result of a loss of earnings incurred. A separate letter has been sent to business customers detailing how they can make a claim.

The Drinking Water Inspectorate has launched an investigation into the cause of the contamination and UU also faces a parliamentary inquiry into the incident.

Public Health England has stated that there have been no confirmed cases of sickness linked to the water supply in the area to date.

UU customer services director Gary Dixon said: “We’re satisfied that the water at all our customers’ taps is now safe to use as normal. We thank everyone for their patience and understanding during this difficult time.”