The warning urged residents to boil water for drinking and for food preparation until further notice.
Nousiainen resident Maritta Lehvonen said that many families including her own had been struck down by a stomach bug.
Lehvonen said that she herself fell ill Thursday night and that the illness spread to most of the rest of the four-person family afterwards.
”Last week I noticed that the tap water was grey and cloudy like an alcopop drink, I had to really run the water out,” she told Finnish news agency STT.
”In a local [Facebook] discussion group there are many families where healthy adults fell sick first.
Southwest Finland daily Turun Sanomat reported Saturday that the local health centre in Nousiainen had been visited by between three and five patients with stomach complaints daily.
Lehvonen said that health centre records do not reflect the true number of people who have been ill. ”The number of people who called the health centre to describe their symptoms doesn’t tell how many visited their occupational health services, treated themselves or sought care in the private sector,” she noted.
River water contamination?
Municipal officials issued Sunday’s warning after water samples tested on Saturday suggested a bacterial contamination.
Lehvonen called for more specific information from local authorities about whether the stomach bug outbreak was caused entirely by contaminated water or if it was also caused by a virus.