Can we swim here? Measuring recreational water quality with community science
E. coli Guidelines for Freshwater in Canada
- Beach Action Value (BAV), single sample: ≤ 235 CFU / 100 mL
- Geometric Mean (over time, multiple samples): ≤ 126 CFU / 100 mL
Learn more: Guidelines for Canadian Recreational Water Quality, 2024
Ontario recreational water protocol
- Geometric mean concentration (minimum of five samples): ≤ 200 E. coli / 100 mL
- Single-sample maximum concentration: ≤ 400 E. coli / 100 mL
Learn more: Recreational Water Protocol, 2019
In September 2025, Water Rangers staff tested two popular recreational water sites near Ottawa, ON, where locals like to swim! We visited Parc Moussette (Gatineau, QC) on September 3 and Lac McGregor (Val-des-Monts, QC) on September 9.
Testing with two ‘community science’ methods
ROTH R-Cards provide a simple culture-based test that estimates E. coli levels by showing colonies as coloured spots. We’ve been using this with volunteers in the UK and in the Lake Erie region as a test that gives us an idea of bacteria levels, but can be easily incubated at home.
Bactiquick is a portable water-testing device that delivers broad bacterial detection (beyond just E. coli) in about 15 minutes, along with geolocated results via a smartphone app. Bactiquick is intended for rivers and lakes with high refresh rates (it doesn’t work in stagnant water or ponds). It’s a new product that’s being used in the UK to answer people’s questions quickly, and now we want to bring it to Canada!
These tools are low-cost and easy to use, giving community scientists timely insights into water quality between official monitoring schedules, so you can imagine we’re pretty excited to share these tools with our community!
September 3: At Parc Moussette, conditions suggested a higher risk to swimmers
Over the summer, Parc Moussette had some beach closures; we think it was due to the Canada goose population!
On September 3, we tested at Parc Moussette using three 1 mL R-Cards and took the average results. Results returned an average of 667 CFU/100 mL of E. coli, which is above Health Canada’s single-sample guideline.
When we tested with Bactiquick, we received a “Yellow” light and a score of 56 (medium risk), indicating elevated bacterial presence. This result corroborates the elevated E. coli counts from the R-Cards.
Both results indicate a potential health risk for swimmers at the time of testing.
These findings differed from the City of Gatineau’s official beach monitoring, which had reported that the water had met water quality guidelines on August 30, just four days earlier. The City of Gatineau tests Parc Moussette twice per week during the swimming season, and results are shared on platforms like Swim Guide.
Our results highlight how water quality can change quickly, like after rainfall, wildlife activity, or upstream inputs, in ways that scheduled sampling might not capture.
September 9: By contrast, tests at Lac McGregor showed very low bacteria levels
Lac McGregor is a popular recreation spot, but not an official beach. A potential health scare earlier this year spooked residents about the safety here, so we were keen to test. R-Cards results from September 9th (in triplicate) showed a reading of 0 CFU/100 mL (no detectable E. coli). BactiQuick showed a ‘green light’ and a score of 16 (with an indication of low health risk).
Both methods’ results suggested that water quality was excellent at the time of testing. These results also raised a discussion about detection limits: at very low concentrations, E. coli may not be detected with the 1 mL R-Cards. We are considering offering a more sensitive version that can detect as low as ~33 CFU/100 mL. We had to wait 24 hours for our R-Cards results, so we were very pleased to receive the Bactiquick results in 15 minutes. In both cases, we know that local residents will be interested in the results at the lake they use, but it does not receive official monitoring!
Bacteria and other risks in recreational waters
Recreational waters can contain bacteria, viruses, and other pathogens that can cause different health problems. Most commonly these lead to skin, ear, or eye infections and stomach illnesses (diarrhea, vomiting). In rare cases, especially for people with weakened immune systems or certain medical conditions, bacteria can lead to severe infections or bloodstream infections. A few of the many organisms and hazards to be aware of:
- E. coli — an indicator of fecal contamination in freshwater; high levels are linked to increased risk of gastrointestinal illness.
- Enterococci — commonly used as an indicator for marine (saltwater) contamination.
- Vibrio spp. (e.g., V. vulnificus, V. parahaemolyticus) — found in warm, salty or brackish water; can cause gastroenteritis and wound infections; some strains can be severe for people with liver disease or weak immunity.
- Pseudomonas aeruginosa — associated with swimmer’s ear, skin rashes, and folliculitis; common in pools, hot tubs, and sometimes natural waters.
- Salmonella, Shigella, Campylobacter — enteric bacteria that can cause diarrheal illness; they have occasionally been linked to contaminated recreational water.
- Norovirus and other viruses — can spread in recreational water and cause acute gastroenteritis.
- Cyanobacterial (blue-green) blooms — produce toxins (not the same as infectious bacteria) that can cause skin irritation, vomiting, and more serious effects.
Because testing for every pathogen is impractical, monitoring programs often test indicators (like E. coli or enterococci). High indicator counts suggest a greater chance of unsafe water for swimming. BactiQuick‘s health risk score looks at the combination of ‘gram negative’ bacteria, meaning we can look at health risks from dangers beyond E. coli, which is very exciting for us!
About the tools
Interested in getting a Bactiquick device?
We’re excited by the research and the user experience of this and are working to bring Bactiquick to Canada! If you’d like to be amongst the first to get one, get in touch with us.
Bactiquick
A handheld device that measures bacterial activity in under 15 minutes. It does not identify specific bacteria but provides a quick indicator of overall microbial (Gram-negative bacteria) presence. Bactiquick is useful for rapid checks of health risk or complementing E. coli culture tests.
Roth R-Cards
Cost-effective (~$20 per triplicate sample) and easy to use. Volunteers collect three 1 mL samples onto cards in the field, incubate them at 35 °C for ~24 hours (we use egg incubators!), and count visible colonies. Results can appear within 8 hours, though waiting longer improves accuracy. These are being used by our community groups in the UK and across Canada as a preliminary ‘coarse’ indicator of bacterial contamination. Basically, it isn’t sensitive enough for swim risk, but it is sensitive enough to detect serious contamination from runoff and sewage (from the city or a septic system).
We’re so excited to offer ways to test for bacteria without sending samples to a lab.
Let us know if you have any questions as we grow our resources in this area!