PUBLIC health authorities are waiting to hear if water from springs and wells around the Malvern Hills is free of bacterial contamination.
Notices went up on 12 public water sources around the Hills in November after water samples proved to be contaminated by the bacteria.
The signs warned visitors about the contamination and said water taken from the springs should be boiled before drinking.
Yesterday (Thursday) staff from Worcestershire Regulatory Services returned to the hills and took a new round of samples from the water sources. They are expecting to have results back from the labs in five to ten days' time.
Mark Cox, the senior practitioner in the land-air and water quality team, said the contamination was caused by coliform and other bacteria from animal droppings left by rabbits and livestock.
He said: "We test 12 water sources around the hills four times a year, and after the November test, the results were that contamination was present at all 12.
"Contamination is by no means unknown at some of the sites, but it's unusual to have all 12 fail at the same time, especially ones such as St Ann's Well, Hayslad and Lower Wyche, which are usually clean."
He said that contamination can come and go according to variations in the environment, such as different weather conditions.
"Very wet weather such as we've had recently, could have the effect of diluting the contamination, whereas when we have droughts, the rate of contamination goes up," he said.
John Harcup of the Malvern Spa Association and a retired GP, said: "Contamination of water sources has been a problem in the past at certain sites, such as the Beauchamp spout in Cowleigh Road, which we advise people never to drink from. But it's unusual to have all of the sites contaminated at the same time.
"People who regularly drink water from the spouts at Hayslad or Evendine have probably built up a good degree of immunity by now, but I'd advise people to boil water anyway to be on the safe side."
The only public water source that was unaffected was the Malvhina spout on Belle Vue Terrace in the town centre, where the water is processed by a treatment system maintained by Malvern Hills District Council.
Water bottled by the Holywell Malvern Spring Water from its source at Malvern Wells is also unaffected, at the company uses top-quality filtration equipment to ensure the water's purity.