Possible scam artists are calling some Atlanta residents about false testing of chlorine levels in tap water, according to the Atlanta Department of Watershed Management.

The department said in a press release that it is not testing chlorine levels and does not have any company doing so on its behalf. The people calling about the phony water testing reportedly offer a $25 gift card in exchange for a response, the department says.

“Please be on alert for potentially misleading calls and be very cautious in allowing people to access your homes,” said Watershed Management Commissioner Kishia L. Powell in the press release.

Anyone contacted about water testing can call the city’s ATL 311 Customer Service Center at 404-546-0311.