PORTSMOUTH — A consultant hired by the city estimated it will cost $18 million to $25 million to run a water line to homes and businesses off Breakfast Hill Road in Greenland.

Keith Pratt of Underwood Engineers said based on that estimate, it would cost about $85,000 per property to run the new water line to 240 homes and five businesses.

“It’s not an inexpensive undertaking,” he said during Monday’s City Council meeting about building the infrastructure and running the new water line to Breakfast Hill in Greenland.

The town of Greenland is seeking the water-line extension because of fears that chemicals leaching from the Coakley landfill will contaminate water wells in the area.

The Coakley Landfill Group, which is responsible for the remediation of the Superfund cleanup site, was recently ordered to provide filter systems to the Breakfast Hill Golf Course and a nearby home when they were contaminated by the suspected carcinogen 1,4-dioxane. The landfill is located in Greenland and North Hampton.

The EPA describes 1,4-dioxane as a “likely human carcinogen” by “all routes of exposure.”

“Short-term exposure may cause eye, nose and throat irritation; long-term exposure may cause kidney and liver damage,” the EPA says.

Pratt told the City Council that Portsmouth currently provides water to parts of Route 33 and Post Road in Greenland.

The current water system ends at the intersection of Post Road and Breakfast Hill Road, Pratt says.

Underwood Engineers estimated that by adding the additional homes and businesses in Greenland, the demand on Portsmouth’s water system would increase 35,000 gallons a day on average.

That would be roughly a 0.8 percent increase on an average day, Pratt said.

City Manager John Bohenko stressed that there has been no commitment made by the city to extend the water line farther into Greenland or to pay for any of the costs.

He added such a commitment would be a “major policy decision for the city.”

“We would look at having to discuss this agreement with Greenland first,” Bohenko said. “Typically, we do not spend our money up front.”

Underwood’s recommended plan for the project calls for extending the city’s water line from Post Road to Lafayette Road through 9,000 feet of 12-inch transmission pipe.

The city would also need to build a new elevated 500,000-gallon storage tank on Breakfast Hill Road “to maintain pressure,” Underwood has said.

The landfill in Greenland and North Hampton is a Superfund cleanup site that accepted waste from 1972 to 1982 and then incinerator waste until 1985. It was capped in 1998.

The CLG is made up of municipalities and private groups that used the dump. Portsmouth is responsible for 53.6 percent of the CLG remediation costs and together the municipalities are responsible for more than 60 percent.

People living near the landfill have been concerned for years that contaminants leaching from the site will contaminate their drinking water wells, especially since 1,4-dioxane and PFAS have been found at high levels in monitoring wells at the landfill.