A new contract of the town’s public works employees, including raises and capping their pension benefits, was passed unanimously by the Board of Selectmen Monday night.

The three-year contract, which must also be approved by the Representative Town Meeting, includes raises of 2 percent retroactively for the 2014-2015 fiscal year, and 2.5 percent in the following two fiscal years. The agreement covers 28 employees.

Like contracts approved last year for four Board of Education unions, the three-year contract will put union members on a high-deductible insurance plan.

The plan has a deductible of $2,000 for the single person, and $4,000 for a family, according to W. Lee Palmer Jr., the town’s human resources director.

The cost increase of the contract in the first year is $90,000, which drops to $40,000 in the second year because of the savings on health care, according to town administrator Kate Buch.

Under the contract, workers will be limited to receiving a pension of 70 percent of their final salary in retirement, officials said.

The group of employees who have 25 years of service by July 2017 will be eligible to receive up to 75 percent of their final salary at retirement under the contract.

“We do feel this is a good settlement for the town and also fair and equitable for the bargaining unit,” Palmer said.

The town is also negotiating a new contract with rank-and-file police officers, Palmer said.

Darien Health Director David Knauf also made a presentation recapping water quality testing for Darien’s beaches this year and addressed a report by Save the Sound which raised concerns about water quality. The group, which is part of Connecticut Fund for the Environment, gave a “C” rating to water quality at Darien’s beaches.

Knauf said the report were skewed because Darien did several tests after significant rainfall events when bacteria is more likely to exceed EPA standards.

The water at Pear Tree Point and Weed beaches tested during or after rainfall exceeded EPA guidelines 30 percent of the time at Pear Tree Point and 25 percent of the time at Weed Beach from 2010 through 2014, according to town statistics.

The town preemptively closes beaches after 1 inch of rain falls within 24 hours.

This year, the town did no testing during or after rainfalls and had water quality grades of B+ for Pear Tree Point beach and an A- under Save the Sound’s criteria.

“It (the ranking) is not accurate because we were looking for bacteria and . . . were looking for something that skewed our result,” Knauf said. “When other towns test they will not test anytime near when it rains and the report makes no representation that all the samples were collected in the same way.”

Knauf said Darien is taking part in a $60,000 DNA source tracking study along with Westport, Weston, and other shoreline communities to identify the source of bacteria in town waters. When complete, health officials should be able to identify whether bacteria counts in water come from human waste, wildlife, birds, or just urban run-off, Knauf told the selectmen.

“We have our fingers crossed because we’re not sure what we’ll find,” Knauf said. “But it will be excellent to have a full health related assessment of the state of the water.”