Maybe water was on everybody’s mind because of the recent water-main break in Prince George’s County. But in the past two weeks, people posing as water utility workers have shown up at houses in at least two area counties and may have helped in thefts from both, authorities said.

The most recent incident occurred Tuesday at a house on Elson Street in the Chillum area of Prince George’s, county police said. They said a man told a resident he was a water employee, there to check on a potential problem.

Once the first man was admitted, police said, an accomplice sneaked in and took money.

Similar incidents have been reported in many parts of the country. In several, the impostor apparently augmented his credibility by holding a clipboard.

A clipboard was carried by the man who came to a door July 18 in Fairfax County, police said. After claiming he needed to “check something,” police said, he was escorted to the back yard. While he was there, police said, an accomplice “may have entered” the house and taken money from a purse.

Authorities have urged residents to demand proper identification.