Napa Valley Lake is an earth dam located in Napa County, California, built in 1990. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 40 ft40 ft tall and 2,170 ft long, taller than 86% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Napa Valley Lake
Napa Valley Lake is a dam in Napa, California. The dam is owned by Langtry Farms, LLC (private). It impounds the Tr Putah Creek.
The dam stands 40 feet tall and stretches 2,170 feet across, creates a reservoir covering 17 acres, has a maximum storage capacity of 200 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1990, the structure is 36 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 10/13/2025.
At 40 feet, this dam is taller than 86% of dams nationwide.
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Location
| State | California |
| County | Napa |
| River/Stream | Tr Putah Creek |
| Coordinates | 38.74660, -122.41170 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 2,170 ft |
| Year Completed | 1990 (36 years old) |
Storage & Hydraulics
| NID Storage | 200 acre-ft |
| Max Storage | 200 acre-ft |
| Surface Area | 17 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | Langtry Farms, LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/13/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01256 |
| Federal ID | CA01256 |
| More Info | State Dam Safety Program |