In two letters dated June 10, Attorney General Martha Coakley told the town that she was in opposition of the original net-zero nitrogen bylaw and supported the repeal approved by spring Town Meeting.

"The bylaw fails to define nitrogen net-zero and is therefore unconstitutionally vague," she wrote. "A statute which either forbids or requires the doing of an act in terms so vague that men of common intelligence must necessarily guess at its meaning and differ as to its application, violates the first essential of due process of law."

The net-zero nitrogen bylaw was passed by Town Meeting voters in October 2010. The standard required that developers contribute no new nitrogen to the watershed. The bylaw was repealed at Town Meeting in April, with Board of Health members and the Coalition for Buzzards Bay citing the difficulties involved in trying to enforce something that has never been enforced anywhere.

The net-zero nitrogen standard stemmed from recommendations in the “Wareham Nitrogen Consensus Plan,” a 41-page action plan containing a list of 15 agreed-upon recommendations to clean up the nitrogen in Wareham’s water, written in 2010.

Five months after the consensus group issued its report, the net-zero nitrogen bylaw covering new developments of 10 or more units was submitted by the Board of Selectmen to last fall’s Town Meeting warrant. After contentious debate, it passed by a two-thirds majority, and responsibility was handed to the Board of Health to draft enforcement regulations.

After seven months the Board of Health found the regulations could not be completed, prompting the effort to repeal the bylaw.

No such net-zero nitrogen standard currently exists anywhere, according to the Environmental Protection Agency.