Lake William
High HazardSatisfactory ConditionEmergency Action Plan: No
Location
| County | Napa |
| River/Stream | Tr Milliken Cr |
| Coordinates | 38.36170, -122.22310 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 66 ft |
| Dam Height | 66 ft |
| Dam Length | 575 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 340 acre-ft |
| Max Storage | 340 acre-ft |
| Surface Area | 16 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | William E. Jarvis |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/17/2025 |
| Emergency Action Plan | No |