PROVIDENCE — It could have been a one-day trial, but Justice Michael A. Silverstein didn’t immediately rule on the legality of the town of Johnston’s plan to sell water to the fossil fuel power plant proposed for Burrillville.

Silverstein simply said he would take the case under advisement, meaning that he will likely issue a written decision in the coming days or weeks. Silverstein retires Sept. 30 and if he doesn’t act by then, the case will be assigned to a new judge.

The town of Johnston, Invenergy Thermal Development LLC, the Conservation Law Foundation (CLF), and the town of Burrillville made their arguments and counterarguments by noon on Aug. 20. Most of the discourse focused on the 1915 Act, which was passed by the General Assembly in that year to set the rules for how the Providence Water Supply Board sells water from the Scituate Reservoir.

At the heart of the debate are six words from the 1915 Act: “other ordinary municipal water supply purposes.”

Jerry Elmer, senior attorney for CLF, told Silversetin the words mean that cities and towns that buy water from the Providence Water Supply Board can only use that water for local purposes.

The attorneys representing the town of Johnston and Chicago-based Invenergy said the lack of an explicit prohibition in the 1915 Act means that cites and towns can resell water as the please, especially if it supports local businesses.

Attorney William J. Conley Jr. said the language of the 1915 Act implies that municipalities have an obligation to offer water for commercial and industrial use. Conley also noted that other power plants, such as the Ocean State Power natural-gas energy facility in Burrillviile, uses cooling water trucked in from other municipalities.

Invenergy is counting on the Johnston water to cool the proposed Clear River Energy Center. It has a contract to buy water from Fall River, Mass., as a backup water supply. Benn Water & Heavy Transport Corp. of Hopkinton is under contract to transport the water by tanker truck from both communities.

Elmer responded by comparing the practice to other unenforced laws, such as prohibitions against pollution that flows freely into rivers.

“Just because many people violate a law doesn’t mean that it is not still a law,” Elmer said.

Gregory Schultz, special assistant to the state attorney general, noted that if cities and towns could resell water from Providence then there is nothing preventing them from reselling it to any customer or city like New York or Boston that may be suffering from a lack of water.

Burrillville’s attorney, Amy Veri, said the 1915 Act doesn’t allow “for profit exploration of natural resources.”

Invenergy’s attorney, W. Mark Russo, said the vague phrase was “left undefined so it could be flexible.”

“They had no idea in 1915 what uses (for water) would be ahead,” he said.

After the court session, Paul Roselli, president of the Burrillville Land Trust, said it’s clear that Invenergy doesn’t deserve water from the Scituate Reservoir.

After getting rejected by two water districts in Burrillville to supply cooling water, Invenergy went outside the town looking for a water source. Woonsocket turned down the offer, but the Johnston Town Council approved an agreement of $18 million over 20 years.

In March 2017, Burrillville and CLF sued the town of Johnston and Invenergy in Providence County Superior Court over the legitimacy of the water deal.

The $1 billion Clear River Energy Center awaits state pollution permits and approval from the state Energy Facilities Siting Board. Hearings for the application resume Sept. 4 at the Office of the Public Utilities Commission in Warwick.