JOHNSTON — The town will not comply with a new state health regulation that calls for municipal water systems to ensure that each home will have a special valve to prevent any backflow of contaminants into the public water supply, according to Mayor Joseph M. Polisena.

Community water systems across Rhode Island must notify the state Department of Health about their progress on the initiative by June 30.

“I’m not doing this,” said Polisena, who controls a water system that supplies about 1,750 homes in Johnston.

“I’m trying to be a realist with the economy,” Polisena said. “In case the Department of Health doesn’t know it, things are bad. I don’t have the manpower and womanpower to go out and enforce this.”

He called the new requirement another “senseless mandate” delivered by the state’s lawmakers.

“Our water quality is excellent,” Polisena said. “I don’t know why all of a sudden they would mandate this. I guess the Department of Health doesn’t have enough things to do.”

The new regulation is an offshoot of a law that the state legislature approved in June of 2007.

It calls for each “community water system” to set up a program for the installation of protective control valves at all service connections, including residential homes. Each system serving more than 500 people must certify that it has established such a program by the end of the month.

The Providence Water Supply Board and the Kent County Water Authority have already established such programs, according to the Health Department’s principal sanitary engineer, Susan H. Rabideau, who estimates the cost of the required valve at about $300, including installation.

A spokeswoman for the department, Annemarie Beardsworth, said the state will try to help Johnston meet the requirement.

mreynold@projo.com

Correction: An earlier version of this story featured a headline incorrectly referencing a community other than Johnston.