Provided by Prince William County Service Authority
On May 19, 2018, the Prince William County Service Authority experienced a sanitary sewer overflow (SSO) at its Powells Creek sewage pump station after a severe thunderstorm caused power fluctuations that shut down pumps inside the facility. The Service Authority quickly contained the overflow and identified no impacts to public health or the aquatic life in Powells Creek.
During major rain events, many utilities have difficulty keeping up with the flow running through their sewer systems. Heavy rain typically results in more inflow and infiltration (I&I) into a sewer line, which can result in an SSO. In addition, lightning and high winds can cause electrical faults in a utility’s sewage pump stations.
The Washington, D.C. metropolitan area has received an unusual amount of heavy rainfalls and stormy weather this summer, with nearly 24 inches falling in Prince William County since May 1. Over the last three years, the Service Authority has experienced two SSOs, including the May 19 event. By contrast, there have been 153 SSOs in Northern Virginia during the last 12 months, due in part to the extensive rainfall the area has experienced.
The Service Authority reported the May 19 SSO to the Virginia Department of Environmental Quality (VDEQ) in less than two hours. The Service Authority also placed signage in the area of the SSO advising nearby residents of the overflow and made the information public in its June Board of Directors meeting minutes.
The Service Authority performs a number of preventative maintenance measures to keep its sanitary sewer system in good working order. These include video inspections of sewer mains and manholes and a sewer main and manhole rehabilitation program.
The Service Authority also regularly examines and repairs sewer mains and manholes near bodies of water. These inspections accounted for nearly one third of the lines inspected in the Service Authority’s sewer system in 2018. In addition, the Service Authority performs weekly physical inspections of each of the sewage pump stations in its service area, including the Powells Creek sewage pump station.
Moving forward, the Service Authority will substantially expand its public notification process over and above regulatory requirements for reportable SSOs. This process will include posting notifications on the Service Authority website (pwcsa.org) and social media accounts as well as increased communication with public officials. The Service Authority will also place signs in English and Spanish at the site of any SSO that enters a body of water.
As the Service Authority focuses on enhancing its communication protocols, it also encourages customers to help keep the sanitary sewer system in good working order. This includes not flushing wipes down the toilet and not pouring cooking grease down drains.
The Environmental Protection Agency (EPA) states that “a few SSOs may be unavoidable. Unavoidable SSOs include those occurring from unpreventable vandalism, some types of blockages, extreme rainstorms and acts of nature such as earthquakes or floods.” For additional EPA information about SSOs, please visit epa.gov/npdes/sanitary-sewer-overflow-sso-frequent-questions.