Sanitary Sewer Overflows (SSOs)


On Wednesday, January 10, 2024 the Wellesley Water and Sewer Division was notified and responded to a small number of sanitary sewer overflow (SSO) events at 54 Cliff Road, Colburn Road across from Brown Park, and just behind Bates Elementary School near Boulder Brook. 

What is a SSO?

A Sanitary Sewer Overflows (SSO) is an unintentional discharge, spill, or release of untreated wastewater to the environment or a property prior to reaching a treatment facility.

Causes of SSOs or Sewer Backups

SSOs occur infrequently, when the capacity of the sewer system is exceeded—usually due to extreme conditions such as heavy rainfall or an obstruction or break in sewer lines. During such events, flow may be discharged to local receiving waters, without treatment, as a last resort to reduce the risk of sewage backing up into homes and businesses.

Effects of SSOs

Public health officials recommend avoiding contact with SSO discharges in receiving waters for up to 48 hours after the discharge has ended, as there may be increased risks due to exposure to potential disease-causing organisms and pollutants. Untreated sewage overflows into basements and can cause property damage and threaten public health.

SSO Notification

In January of 2022, Notification Requirements to Promote Public Awareness of Sewage Pollution (314 CMR 16.00) was put into effect by the State of Massachusetts Department of Environmental Protection (MassDEP). This regulation establishes requirements and procedures for notifying the public of certain types of wastewater discharges to the environment.

If you are interested in receiving a public advisory notification from the Town of Wellesley, if a reportable event was to occur, please sign up here.

When a discharge or overflow occurs, the Town of Wellesley Water & Sewer Division sends out a public advisory notification. On business days, this website will be updated within 8 hours of the notification. During weekends or holidays, this website will be updated on the next business day.

SSO Prevention

The Town of Wellesley is constantly working to upgrade and maintain the sewer system by way of pipe lining, cleaning and inspecting, root treatment and pipe replacement. It is important for the community to help by properly disposing of grease or rags that can block sewer lines. Never pour grease down sink drains or into toilets, and never put solids into grease traps or interceptors.