Sanitary Sewer Overflow

Resident Guide Sanitary Sewer Overflows

What are they?
Why are they a problem?
What can we do about them?

What is a Separate Sanitary Sewer and what is its purpose?
A separate sanitary sewer collects and carries household and industrial sewage from individual buildings such as homes and commercial businesses through a series of progressively larger sewer pipes called the "collection system". A separate sanitary sewer system is different from a combined system which carries sewage and storm water runoff together. Separate sanitary sewer systems are not designed to carry rain water.

The primary purpose of a separate sanitary sewer is to protect public health and the environment. Raw sewage contains disease-causing organisms, which can make people sick if they become directly exposed. Raw sewage also can contain toxic chemicals and offensive odors. The sanitary sewer system carries the raw sewage away from homes to a treatment plant where most of the harmful organisms are destroyed, odors are controlled, and the level of toxic chemicals is reduced.

Why are Sanitary Sewer Overflows a Public Health, Environmental and Economic Problem?
Sanitary Sewer Overflows (SSOs) occur when raw or partially diluted sewage is discharged from a sewer collection system before it reaches the sewage treatment plant. SSOs threaten public health because they can cause people to be directly exposed to disease-causing germs called "pathogens", such as E. coli, which are present in sewage. SSO's can also have negative impacts on the natural environment, causing poor water quality in lakes, rivers and streams, and polluting groundwater, which may be used for drinking water purposes. SSOs can cause economic damage as well, hurting water-dependent businesses, such as commercial fishing and tourism. SSOs that result in basement flooding not only are unhealthy, but also are extremely unpleasant and costly to clean up. Where these chronically occur, property values may be reduced.

How Might You Be Contributing to the Problem of SSOs?
Many property owners are not aware that the maintenance of the sewer line connection between a home and the main sewer line in the street is their responsibility. When poorly constructed or improperly maintained, these connections frequently cause raw sewage to back up in basements.

The connection of roof-gutter downspouts or sump-pump drains directly to the service lateral adds excess water to the main sewer lines, and can contribute to raw sewage being discharged into the streets and other public areas. Homes and small businesses, such as restaurants, can contribute to SSO's by disposing grease into the sewer line. When grease cools, it can form blockages, which then cause the sewer to overflow.

What Should You Do When You Identify an SSO?
Make sure that people are kept away from the area of the overflow, typically a manhole cover. This is especially important for children and pets who may play near the overflow area (street, public park, or local stream). Report the overflow immediately to the appropriate authority. Precautions can then be taken to reduce the risk of public exposure to raw sewage by monitoring the impact of the overflow and ensuring proper cleanup.

What Can You Do to Prevent and Reduce SSOs?
You can prevent and reduce SSOs if you...

Make sure the basement sump pump does not connect to your sewage drain pipes or to a sink or floor drain I your basement. Such connections are illegal. The water from these pumps can overload the sewer causing it to overflow raw sewage into a stream, street, or someone else's basement.
Inspect the gutters on your house or business to see if the down spout connects to a sewer line. Such connections are illegal. If the gutters are connected to the sewer line, have them disconnected. The runoff water from the roof can contribute to an SSO.
Look for and check your sewer clean out. The clean out usually is a small pipe, about 4" in diameter, outside your house that is used to access the service lateral for cleaning the sewer line. You can find it near the house, where the service lateral comes out, and/or near the street, where the service lateral connects to the main sewer line. Make sure the cap to the clean out pipe is on and has not been damaged. Replace missing caps; otherwise, rain can get into the sewer line, causing it to overflow.
Avoid pouring grease down your sink. When the grease cools in the sewer line, it can form clogs and blockages, which then can cause the sewer to overflow or back up into buildings. Grease can also contribute to restricted flow in your home plumbing and service laterals, resulting in costly repairs.
Avoid planting trees and shrubs above or hear the service lateral that runs from your home to the street. Roots can enter and clog sewers, causing them to back up and overflow.
Support local programs that aim to improve the way your sanitary sewer system is maintained and operated. Proper operation and maintenance of the sanitary sewer system are key to preventing the damage caused by SSOs and prolong the life of the sewer system, saving taxpayer dollars.

Seven Terms for Better Understanding SSOs:

Infiltration is water that enters the sanitary sewer system through pipe joints, line breaks or cracks.

Inflow is rainwater from roofs, pavements, yards, manholes and manhole covers that flows directly into a sanitary sewer.

Service lateral is the sewer pipe that connects a house to the main sewer line in the street.

Sewer clean is the small pipe with cap located near the place in a house where the service lateral enters. The clean out is used to free blockages that may form in the service lateral.

Pathogens are organisms in raw sewage that cause diseases, including cholera, dysentery, hepatitis, and gastroenteritis.

Manhole and manhole cover are structures usually found in a street, parking area, or sidewalk that are used to provide access to the main underground sewer lines.

Collection system is the series of progressively larger pipes through which sewage is carried from homes and businesses to a treatment plant. The collection system includes service laterals and the main sewer lines.

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