The Weston Reservoir is part of the greater Boston water supply maintained by the Massachusetts Water Resources Authority. It is located in central Weston, with its principal public access point on Ash Street.

Weston Reservoir
Weston Reservoir Show map of Massachusetts Weston Reservoir Show map of the United States
Location	Weston, Massachusetts, United States
Coordinates	42°20′53″N 71°17′31″W / 42.34806°N 71.29194°W / 42.34806; -71.29194
Type	Reservoir
Primary inflows	240 million US gallons per day (910 ML/d)
Primary outflows	240 million US gallons per day (910 ML/d)
Catchment area	60 acres (24 ha)
Basin countries	United States
Max. length	≈2.2 mi (3.5 km)
Max. width	≈1.6 mi (2.6 km)
Surface area	≈3.5 sq mi (9.1 km2)
Average depth	58 ft (18 m)
Max. depth	110 ft (34 m)
Water volume	200×10^6 US gal (0.76 hm3)
Shore length1	≈4 mi (6.4 km)
Surface elevation	200 ft (61 m)
Settlements	Weston
1 Shore length is not a well-defined measure.

Until the 1960s, the Weston Reservoir was one of two primary distribution reservoirs close to Boston, receiving water from the Sudbury Reservoir via the Weston Aqueduct (placed in service in December 1903). In the 1930s the system was extended to include water from the Quabbin Reservoir, delivered to the Sudbury Reservoir via the Wachusett Reservoir and Wachusett Aqueduct. This system has since the mid-20th century been upgraded to use completely underground facilities downstream of the Wachusett Reservoir. The Weston Reservoir remains a backup connection to two underground storage tanks near the Massachusetts Turnpike elsewhere in Weston.

Walkers extensively use the area around the Weston Reservoir. This reservoir is maintained by the MWRA along with other open distribution reservoirs (Sudbury, Foss, Brackett, Stearns, Norumbega, Waban, Spot Pond, Chestnut Hill and Middlesex Fells) as a backup distribution system. The grounds of this reservoir are also used by the MWRA's Emergency Service Unit for training and storage of emergency trucks and equipment.