Property owners are reminded of the importance of keeping stormwater and wastewater separate. Municipal sewer systems are designed to handle different types of water, and when each property does its part, it helps prevent flooding and reduces pressure on local infrastructure.

When stormwater enters the sanitary system, it can overload the system, resulting in sewer backups in homes, street flooding, higher treatment costs, and cause environmental harm.

• Storm sewers carry rainwater, melted snow, and clean runoff from gutters, storm drains (catch basins), driveway drains, and sump pump discharge directly to local streams, rivers, and lakes. These systems prevent flooding by quickly moving large volumes of non-treated water.
• Sanitary sewers carry water from toilets, sinks, showers, bathtubs, washing machines, and dishwashers to the Wastewater Treatment Plant, where it is treated before being safely released.

What You Can Do as a Homeowner

Proper management of roof drainage, downspouts, and sump pumps plays a key role in protecting your home and the community. Never connect downspouts or roof drainage directly to the sanitary sewer, as this can cause basement backups, street flooding, and higher treatment costs. Water should be directed away from foundations toward yards, ditches, or storm drains. Downspout extensions and elbow pipes should carry water well away from the house, not just into soil near the foundation, and gutters and downspouts should be kept clear of debris and cleaned regularly.

If a sump pump is not operating properly, is allowed to overflow, or is directly connected to the sanitary sewer, groundwater can enter the sewer system and increase the risk of backups into your basement. This may result in foul odours, water damage, and costly repairs. Homeowners should ensure sump pumps are connected correctly to foundation drains and discharge water away from the house toward yards or storm drains.

It’s the law

Environmental regulations, municipal by-laws and the Ontario Building Code prohibit connecting storm drainage to sanitary sewer lines. These requirements apply to construction, renovations, and any updates to plumbing or drainage systems, ensuring connections are installed, maintained, and inspected according to current standards. Homeowners and builders are responsible for meeting these requirements, and non-compliant connections may result in fines and mandatory corrective work.

If you’re unsure how your current property is connected, a licensed plumber can provide guidance and help ensure your system meets current regulations.

More information

Where Does Your Water Go? – Download Printable PDF

Water and Wastewater Services – Municipality of West Nipissing

Ontario Ministry of the Environment, Conservation and Parks (MECP) – F-6-1 Procedures to Govern Separation of Sewers and Watermains