Yorkshire Water has announced that E.coli and a related group of bacteria were found in samples that were collected during the contaminated water incident.
The source of the bacteria has been found and blocked in Thorne,
Yorkshire Water are refusing to name the source at the present time.
Once the bacteria was found Yorkshire Water launched a full investigation into the cause and issued a ‘Do Not Drink’ notice to local residents, which was later changed to a ‘Boil First’ Instruction.
A "Boil First" instruction remains in place.
Charlie Haysom, the company’s Director of Service Delivery, said: “As soon as the bacteria was found we responded by launching a full investigation into the cause of the problem. We’ve now put a permanent solution in place so this incident cannot happen again from this source.
“The sample results have improved significantly, but we need them to be completely clear before we can lift the boil notice. Residents in the affected area must continue to boil their water until we tell them otherwise.
“We’d also like to clarify that we will be issuing the £30 goodwill payments to thank all residents who were originally told on Friday that their water was affected for their patience.”
Warning to boil water before drinking still in place in affected South Yorkshire areas
Yorkshire Water confirmed it had identified the source of the bacteria, and immediately isolated the source from the water network.
A spokesman added: "Once the investigation found the source, external to Yorkshire Water’s network, the company put in place several physical barriers to stop this source from contaminating the water network in Thorne again. "
"Yorkshire Water does not wish to name the source at the moment but is continuing to fulfill its statutory duties under the Water Supply (Water Fittings) Act.