Rock Run
Rock Run is a concrete dam located in Chester County, Pennsylvania, built in 1917. It carries a High hazard potential classification and has a fair condition assessment.
About Rock Run
The primary purpose of Rock Run 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 Pa American Water Company (private). It impounds the Rock Run.
The dam stands 42 feet tall and stretches 583 feet across, creates a reservoir covering 61 acres, has a maximum storage capacity of 1,250 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1917, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/16/2020.
At 42 feet, this dam is taller than 89% 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 Pennsylvania 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 | Pennsylvania |
| County | Chester |
| River/Stream | Rock Run |
| Coordinates | 40.00528, -75.85306 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 42 ft |
| Dam Height | 42 ft |
| Dam Length | 583 ft |
| Year Completed | 1917 (109 years old) |
Storage & Hydraulics
| NID Storage | 1,250 acre-ft |
| Max Storage | 1,250 acre-ft |
| Normal Storage | 1,010 acre-ft |
| Surface Area | 61 acres |
| Drainage Area | 5 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | PA AMERICAN WATER COMPANY |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 07/16/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00059 |
| Federal ID | PA00059 |
| More Info | State Dam Safety Program |