Building on work already underway, the City of Sarnia will implement an action plan to better address the impacts of flooding caused by extreme weather events.

The development and implementation of the plan is in response to last week’s storm event that caused basement flooding across the community, most notably in the Coronation Park area. The plan will include both short- and long-term action items to better prepare City and private-property stormwater / sanitary sewer infrastructure for the impacts of extreme weather.

In the short term the City will focus on improving uptake on its Basement Flooding Grant Program that assists homeowners in the installation of backwater flow valves that prevent sanitary sewer lines from backing up into basements. The program also covers the costs of disconnecting foundation drains from sanitary sewer infrastructure, reducing the likelihood of sewers being overwhelmed during heavy precipitation and backing up.

At the same time the City will move forward with a program to reduce inflow and infiltration (IAI) into the sanitary sewer system. IAI refers to non-sewage water entering the sanitary sewer system, resulting in the system being overwhelmed and backing up during extreme storm events. Over the last two years the City has investigated sources of IAI and discovered no significant sources with City infrastructure. The new action plan will allow the City to move forward with investigating sources on private property — such as downspouts and foundation drains connected to sewers — and assist residents in rectifying these issues.

In the longer term the City will initiate a city-wide flood-risk study originally identified for possible inclusion in the 2023 budget. The study will guide the development of a specific strategy to guide investments in sewer and stormwater infrastructure.

In tandem with the strategy, 2023 budget deliberations will include a capital funding mechanism, such as a dedicated capital reserve fund, to facilitate funding to implement the sewer / stormwater strategy investments.

The City continues to engage with the Province and Federal Government on potential financial support to move forward with critical investments in water infrastructure and relief for flood-impacted residents.

For a full copy of the related staff report please visit