Sudbury Reservoir
🌤 Weather at Sudbury Reservoir by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 24–73 °F | 55–87 °F | 29–78 °F | 15–43 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at Maynard 2, 10 mi away, elevation 205 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
🏆 Hidden Reservoir — 2-billion-gallon reservoir surrounded by protected watershed — Boston’s backup water supply
Sudbury Reservoir is a 2-billion-gallon reservoir in Southborough — part of the Massachusetts Water Resources Authority (MWRA) system that provides backup water supply for the greater Boston area. The reservoir’s protected watershed creates a scenic landscape of forest and open water visible from Route 9 and the Massachusetts Turnpike. While swimming is prohibited, walking trails around portions of the reservoir offer peaceful nature walks in the suburban MetroWest region.
Visitor Information
| Detail | Information |
|---|---|
| Location | Southborough, Worcester County, MA |
| Entry Fee | Free |
| Water | 2 BILLION gallons! |
| Note | No swimming — Boston’s water! |
About Sudbury Reservoir
Sudbury Reservoir in Southborough is part of the Metropolitan Boston water supply system — a 563-acre reservoir surrounded by protected watershed lands. The reservoir and its buffer zones provide important wildlife habitat in the rapidly developing western suburbs of Boston. The perimeter trail offers views across the water.
Sudbury Reservoir in Southborough provides passive recreation around one of Metropolitan Boston’s historic water supply reservoirs. Built in 1875-1878 by the Boston Water Works, the reservoir is part of the Sudbury Aqueduct system — an engineering feat that brought clean drinking water to Boston and ended the cholera epidemics that plagued the city. The surrounding 1,000+ acres of watershed land provide protected green space.
Things to Do
Walking and jogging the reservoir perimeter paths, birdwatching (the reservoir attracts waterfowl and osprey), fishing (with permit), and enjoying views across the water. Swimming is prohibited — it’s a drinking water supply.
Walking the reservoir perimeter trails, birdwatching, fishing (limited), nature photography, and studying the 19th-century water engineering that saved Boston from cholera.
Insider Tips
Protected watershed: Sudbury Reservoir is part of Boston’s historic water supply system. Pro tip: Walking trails around the reservoir offer scenic views but swimming and boating are prohibited. Wildlife: The protected watershed creates excellent habitat for birds and deer.
Best Time to Visit
Fall: Foliage reflections on the reservoir. Spring: Migrating birds. Summer: Shaded trails. Winter: Cross-country skiing.
Frequently Asked Questions
Can I swim in Sudbury Reservoir?
No. As an active water supply reservoir, swimming, boating, and fishing are prohibited. However, walking trails around the perimeter offer beautiful views and peaceful nature observation. The protected watershed supports diverse wildlife rarely seen in suburban settings.
More parks nearby: Callahan State Park is a short drive away, while Hopkinton State Park lies a short drive away.
🐾 Dogs & Pets at Sudbury Reservoir
- Pets allowed? statewide rule
- The Massachusetts Department of Conservation and Recreation (DCR) welcomes dogs on-leash in most state parks, forests and reservations, though a list of specific properties prohibits dogs for safety, health or habitat reasons.
- Leash rule statewide rule
- Leash of no more than 10 feet in on-leash areas; dogs must be on-leash in all parking areas.
- Beaches & swim areas statewide rule
- Dogs are not allowed on DCR coastal beaches or in designated swimming areas of inland beaches from May 1 through September 15; shorebird-nesting beaches are closed to dogs April 1 - September 15.
- Cabins & lodging statewide rule
- Dogs are not allowed in cabins, yurts and the encompassing areas (no pet-friendly cabin program).
- Statewide exceptions statewide rule
- Designated off-leash areas at ~20 properties (e.g. Bark Place at Breakheart Reservation); max 4 dogs per person; dogs banned entirely at Walden Pond, Moore State Park, Sandy Point and Boston Harbor Islands.
Are dogs allowed at Sudbury Reservoir?
The Massachusetts Department of Conservation and Recreation (DCR) welcomes dogs on-leash in most state parks, forests and reservations, though a list of specific properties prohibits dogs for safety, health or habitat reasons. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via mass.gov. More: Massachusetts state parks guide · Dog rules in all 50 states compared
Park Location
Plan your gear for Sudbury Reservoir
From our editorial guides, matched to this park’s activities:
