By CBS 2 Chicago Staff

CHICAGO (CBS) — Residents in southwest suburban Plainfield are being warned to boil their water, after testing found E. coli bacteria in the village’s water supply.

The boil order is expected to last through the weekend, and could even affect schools on Monday.

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Village officials cautioned people in Plainfield not to drink tap water without boiling it first for 3 to 5 minutes. Otherwise, they should use bottled water.

Boiled or bottled water also should be used for making ice, brushing teeth, washing dishes, and preparing food until further notice in Plainfield.

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E. coli bacteria can cause diarrhea, cramps, nausea, headaches, and other symptoms, and are especially harmful for infants, children, and people with compromised immune systems.

It’s unclear what caused the contamination in Plainfield, and the village said their water supplier, Illinois American Water, will investigate. All of the village’s water towers and its ground storage tank will be inspected this weekend, and the village will flush all hydrants.

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The village also will conduct extensive water sampling until the boil order is lifted, when at least two sets of 40 water samples are deemed safe.

CBS 2 Chicago Staff