BRIDGEPORT — Aquarion Water Co. continued on its buying spree, making a Marlborough-based utility its 29th acquisition in the past 15 months.

Terms of Aquarion’s deal to purchase Birchwood Water Association were not announced Wednesday. Brichwood Water has about 275 customers in the eastern Connecticut community.

“The integration of the Birchwood Water Association into our network will allow us to improve water quality for the community of Marlborough, as well aid future development in the town,” said Charles Firlotte, president and chief executive officer of Aquarion, which is based in Bridgeport.

The deal to purchase Birchwood comes a week and half after Aquarion officials announced they had signed an agreement to purchase United Water Connecticut Inc., which serves over 21,000 residents in Bethel, Brookfield, Newtown, New Milford, and Woodbury.

Aquarion now provides water to more than 610,000 people in 47 cities and towns throughout Connecticut, in addition to its service territories in Massachusetts and New Hampshire.