WHAT IS SWIM GUIDE?
Swim Guide is a global program that allows anyone to search for the pollution status based on E. coli presence at beaches or popular swim sites that are actively monitored by environmental organizations. It is a resource for people to be better informed regarding their decision to recreate on the water. The swim guide website also provides information about the swim site - including accessibility and nearby landmarks. Swim Guide sampling is typically completed between April to October during warm weather in our region.
How is Swim Guide Sampling done?
The water sampling for Swim Guide is done over the course of two days. The process begins with preparing the sampling equipment and selecting our rotating site. Then, we travel to each of the 5 sites and collect the samples. We use gloves to keep the sample sterile and a sampling pole to reach from the shoreline into the waterway for collection. Samples are labeled with time and location and brought back to the office to be analyzed.
For the testing process, 1 mL of the water is placed onto a R-Card (used to detect E-coli colonies) with a cover slip and placed into an incubator at 95°F. After approximately 24-hours, the samples are analyzed for any apparent bacterial growth, specifically, E. Coli. The threshold for recreational water quality standard as determined by the EPA is approximately 2.0 cfu per 1 mL of sample for E. coli. This means that if there are more than 2 colonies of bacteria present, the water is labeled as unsafe for recreation at that time.
Water Quality Standards - E.coli
To test whether the water is safe to swim in, float on, or drink, we perform bacterial growth tests on the samples collected. These tests primarily check for the growth of potentially harmful bacteria that can be found in waterways due to combined sewer overflows. Raw sewage contains bacteria like E.coli and types of Coliform which can cause illness if consumed. It can also cause illness for wildlife and generally decrease the health of the ecosystem. Click here to learn more about recreational water standards.
What other data do we collect?
Outside of analyzing the water for E. coli for Swim Guide monitoring, we measure features like pH, turbidity, conductivity, and dissolved oxygen - this allows us to better understand the quality and status of our waterways.
Where do we sample?
For the 2023 Swim Guide Monitoring Season, we sampled 5 locations in Pittsburgh every week. Four of those locations stay the same each week and the fifth site changes so we can capture data of our tributaries and other swim sites.
Interested in proposing a tributary in Southwestern PA for us to sample? Send us an email at firstname.lastname@example.org
Swim Guide sampling is posted weekly on our Instagram and Facebook, so give us a follow if you'd like to see our updates!
Why is swim guide sampling important?
Combined Sewer Overflows in Pittsburgh
Combined Sewer Overflows, also known as CSOs, occur when excess water runoff overwhelms a combined sewer system and causes diluted, untreated sewage to be discharged into streams and rivers. CSOs are not typically a concern on most days when there is little to no rainfall, but when there is at least 1/10 of an inch of rainfall, the combined sewer system is in risk of overflowing. Learn more about Sewer Overflow Advisories here.