With the recreational water use season upon us, we would like to remind boaters and other waterfront users to check our sewer overflow map after heavy rainfalls. To reduce overflows, in partnership with the City of Kingston, we have set a 20-year target to separate 100 per cent of the combined sewers in the municipal sewer system, by 2043.

Kingston’s waterfront is a clean, safe place to swim, fish or boat. But bacteria levels in lakes and rivers are higher up to 48 hours after heavy rainfall and swimming is not recommended during that time. Sewer overflows can contribute to the problem. Our online map shows where sewer overflows have occurred in real time.

In 2022, we managed approximately 35.8 million cubic metres of wastewater. Almost all of it (99.9 per cent) was fully treated and returned to Lake Ontario as natural resource quality water. Approximately 0.1 per cent of sewage was released from overflows and bypasses, typically when the sewers became too full due to heavy rains and rapid snow melts, or when equipment failed. 

When Kingstonians or visitors plan to boat, fish or swim in Lake Ontario within 48 hours after heavy rain, they are encouraged to first check the map at www.UtilitiesKingston.com/Overflows. Sewer overflow locations affecting the Great Cataraqui River, the Little Cataraqui Creek, and other surrounding bodies of water are also shown.

How we are reducing sewer overflows

Along with the City of Kingston, we will continue to separate combined sewers to further reduce combined sewer overflows. Planned near-term work includes Victoria Street, from Johnson to Union; Union Street, from Victoria to Collingwood; Earl Street, from Victoria to Collingwood; Princess Street, from Division to Alfred; and on Gore and Bagot Streets, and Couper and Collingwood Streets.

Overflows of sewage are a historical remnant of the evolution of the sanitary sewer system in the City of Kingston. Overflows have been occurring for decades and are a problem that exists in most major cities around the world. When a sewer overflow reaches the lake or river, it contributes pollutants to the environment.

As per our Water and Wastewater Master Plan, the preferred method for reducing sewer overflows is to separate combined sewers—sewers that collect both sewage and stormwater runoff and can get too full during heavy rain events.

In 2007, the municipal sewer system still included 275 blocks of these combined sewers, some constructed 100 years ago. Since that time, we have worked with the City of Kingston to separate nearly half of these combined sewers and are well-positioned to separate the remaining 51 per cent by 2043.

Resources available

More information including a brief animated video about sewer overflows, our real-time sewer overflow map, ongoing projects and frequently asked health and technical questions are available at UtilitiesKingston.com/Overflows.