Ottawa Public Health looks to continue weekly testing at public beaches next summer

A lifeguard patrols an Ottawa beach. (Andrew Adlington/CTV News Ottawa)

Ottawa Public Health is recommending the city continue with weekly water quality testing at public beaches next summer, saying neither the daily nor weekly E.coli testing “reliably reflect real-time water conditions.”

The health unit says its focus will now shift towards general water safety measures at Ottawa’s beaches, including drowning prevention.

The health unit moved to weekly, instead of daily, E-coli bacteria testing of the water at Mooney’s Bay, Britannia, Petrie Island and Westboro beaches this summer.

The move sparked criticism from some organizations and individuals, with the Ottawa Riverkeeper warning testing once a week, “is not frequent enough to catch changes in water quality in an urban environment.”

In a report for the Ottawa Board of Health meeting on Sept. 15, staff said the daily testing of water at Ottawa’s beaches “led to public misinterpretation of delayed lab results as real-time water quality indicators” that it was safe to swim. The report notes the daily testing took 18 hours to process the results.

The report, prepared by Environmental Health strategic programs and project officer Phillip Boyd, says Ottawa Public Health’s beach monitoring strategy now “emphasizes real-time environmental indicators alongside retrospective lab results of E.coli.”

“This change supports a more comprehensive public health risk approach by focusing on environmental conditions and physical safety risks—such as beach supervision, rainfall, wind, and wildlife activity—that better reflect current swimming risks, while still providing similar levels of information on water fecal contamination,” the report said.

“It also enables clearer public messaging about risks and reduces inaccurate swim and no swim recommendations.”

The health unit says an analysis of weekly and daily testing showed the accuracy of weekly testing is “not meaningfully lower than daily testing,” and the accuracy varies by beach.

“The chance of the previous test result correctly predicting when the water quality does not meet the standard (‘positive predictive value’) is low (less than 50 per cent) in both daily and weekly testing,” the report said.

“When “no-swim” was recommended, the previous test results triggered unnecessary “no-swim” recommendations 8.8 per cent of the time (‘false positive’) with daily testing and 11.7 per cent of the time with weekly testing.”

The health unit says daily and weekly testing results are “useful for understanding the trends in water quality over a season,” adding neither “daily or weekly testing methods reflect real-time water conditions.”

The OPH epidemiology and surveillance team will monitor trends in diseases of public health significance and analyze for water-related illnesses reported to the health unit. The recreational water team is also required to investigate complaints related to beaches, according to public health.

Ottawa Public Health says most Public Health Units across Ontario conduct weekly testing of beaches.

A total of 14 Ottawa residents had a lab-confirmed infection with an enteric illness linked to city beaches between 2014 and 2023.

Water safety campaign

The report recommends Ottawa Public Health be directed to continue to work with partners to focus on water safety at beaches.

The health unit is recommending the city’s Recreation, Culture and Facility Services department adopt a general advisory for all municipal beaches, “encouraging personal health precautions before, during and safety swimming.”

The advisory will recommend people avoid swimming with open wounds, refrain from swallowing water and showering after swimming at beaches along the Ottawa River and Rideau River.

Signs have been installed at Ottawa’s beaches to encourage personal health precautions, and the OPH website was updated to “focus on the importance of personal health precautions at all times” when swimming in lakes and rivers.

“Shifting the focus to personal health protection in all natural water conditions as your best way to minimize risk presents challenges, particularly as past experience shows some residents relied solely on delayed lab results as real-time indicators of water quality,” the report says.

“This made behaviour change difficult.”