Collection System Improvement Program

Sewage spills - or sanitary sewer overflows (SSOs) - in Winston-Salem and Forsyth County have been drastically reduced in recent years. This is primarily due to proactive measures by Winston-Salem/Forsyth County Utilities as part of our Collection System Improvement Program (CSIP). Through a mixture of targeted repairs to improve the condition of existing pipes and proactive maintenance to clean sewer lines and prevent buildup of debris that can cause blockages, WSFC Utilities is taking steps to ensure that rates of SSOs continue to drop as they have in recent years.

CSIP Overview (PDF)

DTWS from east

What is the Collection System Improvement Program?

The CSIP is a multi-year effort established by WSFC Utilities to improve the condition and performance of the local wastewater collection system. The WSFC Utilities wastewater collection system includes 1,825 miles of sewer lines and 45 lift stations with some pieces of the system dating back to as early as 1907. Each year the system collects and conveys as much as 14 billion gallons of wastewater to one of two wastewater treatment plants. Through the CSIP, WSFC Utilities identifies and prioritizes maintenance and rehabilitation needs within this system to ensure that the system continues to operate as efficiently as possible for the 381,000 residents and commercial customers in Winston-Salem and Forsyth County.

Condition assessment projects known as Sewer System Evaluation Studies help us identify and rehabilitate defects within the collection system. This is done by cleaning, televising, inspecting and smoke testing the sanitary sewers and manholes.

You can learn more and find out if we'll be working in your neighborhood at

SSO crew

What are Sanitary Sewer Overflows?

Occasionally, sanitary sewers will release raw sewage. This type of release is called a sanitary sewer overflow (SSO). These SSOs, or sewer spills are typically the result of blockages or damage to the wastewater collection system that stop the flow of wastewater to treatment plants and cause overflow into the natural environment. Common causes of SSOs include cooking fats, oils, grease, wipes, roots, line breaks and other sewer system defects that cause the wastewater collection system to become overloaded. The EPA estimates that up to 75,000 SSOs occur each year across the US.

WSFC Utilities has drastically reduced the number of SSOs in our system over the past several years. Since 2015 (the year prior to the start of the CSIP), WSFC Utilities has reduced the number of SSOs by over 55%. In FY 2022-23, WSFC Utilities continued to prevent these events and successfully conveyed and treated 99.999% of the wastewater generated by our customers.

Annual SSO count -FY22

What is WSFC Utilities doing to reduce SSOs in the community?

WSFC Utilities is proactively working to continue to reduce SSO events in the community. This includes daily maintenance within the sewer system to remove wipes, grease, roots and other debris that get into the system and are the main cause of SSOs. The primary way WSFC Utilities controls this issue is by actively cleaning sewer pipes and removing these materials from the system. In addition, we are constantly inspecting and repairing sewer pipes that become damaged due to age, environmental conditions, and improper use. Combined, these actions work to consistently keep the system in the best shape possible.

WSFC Utilities Cleaning Activity

WSFC Utilities has purposefully increased sewer cleaning activities within the system to eliminate SSOs. Since the start of the CSIP, WSFC Utilities has maintained the goal of performing an initial cleaning of every pipe in the system, and will have established a recurring maintenance schedule within 10 years. Through the end of FY 2022-23, Year 7 of the CSIP, WSFC Utilities has successfully addressed 71% of the collection system. The combination of performing these initial cleanings and the reoccurring follow-up cleanings means that WSFC Utilities has cleaned more than 2,540 miles of pipe since 2017.

Annual cleaning performance -FY22

WSFC Utilities Rehabilitation Actions

To find and eliminate damage to sewer pipes that can cause SSOs, WSFC Utilities is continuously inspecting and rehabilitating the sewer system. This results in repairs being performed throughout Forsyth County to fix damage to collection system pipes. Since the start of the CSIP, WSFC Utilities has completed more than 773 rehabilitation projects.

CSIP construction

What should you do if you suspect an SSO?

If you suspect a sanitary sewer overflow is happening within the WSFC Utilities collection system, you can report it through City Link. There are many ways to report an SSO. Find your favorite at

Upon reporting, WSFC Utilities first responders will be notified to investigate the area, eliminate any cause of the SSO and mitigate any impact on public health and the surrounding environment. WSFC Utilities is committed to proactively safeguarding public health and the environment through a culture of continuous improvement.