South Kilkenny residents have demanded that the county council identify the source of pollution which is making tap water undrinkable.
Up to 2,000 householders in Mullinavat, Mooncoin and Kilmacow have had to use private wells or parish pumps for their water supply many times over the past year, said Fianna Fail councillor Ms Cora Long.
"Every time there's a flood or a lot of rain, something happens to the water, and for over a week afterwards what you get from your tap is obnoxious. It looks like slurry and smells like slurry," she said.
Ms Long brought a bottle of the liquid, which emerged from a constituent's kitchen tap following a recent heavy rainfall, to last week's meeting of Kilkenny County Council. A single source of pollution, upriver from the water treatment plant at Clonassy, is believed to be responsible, she said.
However, the council's senior executive engineer in charge of sanitary services, Mr Tom Gunning, said there were about 100 farmers in the catchment area and more than one source could be responsible.
He said an ammonia detector had been placed in the river and this triggered an alarm which "automatically shuts down the system" whenever pollution was detected.
The equipment had failed, however, on one occasion recently and perhaps twice in the past year. Officials then had to treat the water with chlorine and this was what gave rise to the offensive smell. The council had appealed to the public for assistance in identifying the cause of the pollution, he added.
Ms Long said the pollution tended to happen at weekends and at night-time and that it should not be difficult to establish the source. "I'm getting a lot of representations about this," she added, "and for the council to simply ask for information from the public is not good enough. We want something to be done."