(CBS) — Precautionary testing of water in Glenview School District 34 turned up some disturbing results.

Four rooms at Hoffman Elementary School are now without water fountains after tests showed water from the fountains contained lead levels greater than 15 parts per billion, the Environmental Protection Agency’s acceptable limit.

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In additions to the fountains at Hoffman, three other fountains – one at Springman and two at Pleasanst Ridge — also showed higher levels of lead.

In an email to families, Superintendent Mike Nicholson said precautionary tests were conducted on 246 water fountains and kitchen-area faucets located in nine school district buildings.

Ninety-seven percent of those locations tested within acceptable lead levels set by the EPA, school officials said.

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“All the information that we have is that it’s very unlikely that our students or staff would have any adverse reactions, health effects, solely attributable to the water quality in Glenview,” Nicholson said.

The source of the lead is still under investigation. School officials believe it’s likely from the fixtures, and not the water supplied by the village of Glenview, which has been tested and found to be safe.

All of the faucets that tested at a high level of lead will remain out of service until they are within safety limits.

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