Putnam Reservoir Dam
Putnam Reservoir Dam is an earth dam located in Fairfield County, Connecticut, built in 1910. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Putnam Reservoir Dam
The primary purpose of Putnam Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Aquarion Water Company Of Connecticut (public utility). It impounds the Horseneck Brook near Greenwich.
The dam stands 35 feet tall and stretches 640 feet across, creates a reservoir covering 105 acres, has a maximum storage capacity of 1,775 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1910, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 05/16/2024.
At 35 feet, this dam is taller than 82% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Connecticut dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Connecticut |
| County | Fairfield |
| Nearest City | Greenwich |
| River/Stream | Horseneck Brook |
| Coordinates | 41.08452, -73.64134 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 35 ft |
| Dam Height | 35 ft |
| Dam Length | 640 ft |
| Year Completed | 1910 (116 years old) |
Storage & Hydraulics
| NID Storage | 1,775 acre-ft |
| Max Storage | 1,775 acre-ft |
| Normal Storage | 1,775 acre-ft |
| Surface Area | 105 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 1,560 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Aquarion Water Company of Connecticut |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/16/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00041 |
| Federal ID | CT00041 |
| More Info | State Dam Safety Program |