Groton — With the cause of a water main break located, Groton Utilities expects to have water restored to customers and Poquonnock Road reopened to one lane of traffic sometime during the overnight hours.

Poquonnock Road (Route 1) between South and Buddington roads was closed Wednesday due to a water main break discovered shortly after 9 a.m.. Groton Utilities notified and shut down water service to about 40 customers along Route 1 from South Road to Plaza Court.

Ledge Light Health District contacted the eight food service facilities involved, according to Emergency Management Director Joe Sastre.

Traffic was diverted around the break throughout the day as Groton Utilities crews worked to locate the source of the break. There are three major distribution pipes in the area of the break under Route 1: a 16-inch main, a 20-inch main and a 24-inch main. The pipes are about 70 years old.

By early evening, crews discovered the break at a specialized T connection, which was probably installed in the 1930s or 40s, and had blown apart, according to Richard Stevens, general manager of the water division for Groton Utilities.

Stevens said a contractor is installing line stops on the 16-inch piping to shut it down completely and allow water to flow to customers sometime in the overnight hours. The line stops will also allow a flushing of the other pipes, which will help clear up sediment in the water.

Repair work expected to continue into the weekend.

Water may be discolored in Groton City and the Fort Hill area near the main, but it is safe to drink.

Traffic is being diverted, police said. Westbound traffic is being detoured onto South Road to Runway Lane to High Rock Road back onto Poquonnock Road. Eastbound traffic is being detoured onto Buddington Road to Gold Star Highway onto North Road.

Police are asking motorists to avoid the area.