'Do not drink' order issued for Harwich drinking water after Dennis fire. What we know.

The "do not drink" order was lifted Thursday .

Harwich has issued a "do not drink" order for the town's drinking water.

Crews were expected to have been flushing the system Tuesday night, after the town found firefighting foam in the water supply, from a fire in Dennis Tuesday. The foam is 100% biodegradable and PFAS-free, according to the town notice. The "do not drink" order was issued "out of an abundance of caution."

The water department will collect water samples and test them. When tests show no contamination, the "do not drink" order will be rescinded.

Residents are advised to use bottled water during the order for drinking, brushing teeth, making ice, washing dishes and food preparation. Town water can be used for laundry and bathing.

The town of Dennis is not under any order, according to Superintendent David Larkowski. The town has not received any complaints of foamy water — which was discovered in parts of Harwich — and after flushing their system on Tuesday evening found no signs of contamination.

"Some kind of backflow event happened from the fire and from the fire departments connecting to the hydrants," he explained. "The Dennis Water District has not experienced any customer complaints or foamy water from anything so any problems were in the Harwich area and not the Dennis area."

A Tuesday fire in Dennis, on Great Western Road, was determined to be the cause of the contamination. Officials believe the water contamination in Harwich is restricted to North Harwich, according to the town notice.

The fire was in a commercial building behind Great Western Deli in Dennis, according to a Facebook post from the Harwich Fire Department. Harwich firefighters arrived shortly before 11 a.m. and were on the scene for about an hour and a half.

The situation was described as "heavy fire" and photos from the Harwich Fire Department show huge clouds of billowing smoke.

Further information on the fire was not immediately available. This story will be updated as more information becomes available.

Reporter Frankie Rowley contributed to this story.

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This article originally appeared on Cape Cod Times: 'Do not drink' order issued for Harwich drinking water after Dennis fire. What we know.