Reducing stormwater entering the system

For more information on separated and combined systems view our FAQs.

There are several methods to reduce stormwater from entering the wastewater system.

• One method is sewer separation. Sewer separation takes place in combined sewer areas when additional pipelines are laid in the area. The new pipeline then conveys stormwater directly to the nearest water body and the older pipeline conveys sewage to a secondary treatment plant (such as the West Point plant). Once these new pipes are in place, the area is considered a separated system.
• Another method of reducing stormwater into the wastewater system is by repairing leaky side sewers. This method keeps rainwater out of the wastewater system, which reduces CSOs.
• In many areas, roof and yard drains have been connected into the wastewater system. Disconnecting and rerouting these drains keeps rainwater out of the wastewater system, which reduces CSOs.
• An emerging method is green stormwater infrastructure (GSI) which uses green solutions to help reduce overflows by allowing stormwater to infiltrate slowly into the ground and cutting the volume of stormwater entering the sewer system.