South Ribble MP Seema Kennedy is pushing UU to provide more information and plans to raise the issue of the cryptosporidium contamination in parliament as soon as it returns from recess.
The Conservative MP said UU still insists it is unable to offer any idea as to the cause of the problems while the investigation by the Drinking Water Inspectorate (DWI) is ongoing.
She added: “I, and other residents, affected by the ongoing boil water notice deserve to be more informed on when this can be expected to come to an end.
“There is an understandable level of frustration with United Utilities for continued vague responses when questioned about when this may come to an end.”
The cryptosporidium contamination has resulted in a boil water notice being in place for more than 300,000 properties across Lancashire since 6 August.
UU has been flushing through pipes and storage reservoirs, and has also now deployed portable ultraviolet (UV) ray equipment to kill off the remaining cryptosporidium.
UU is reported to be facing a “colossal” £15 million hit due to rising customer compensation costs, but the company has said it would not offset this cost by pushing water bills higher.
A version of this story first appeared on wwtonline.