Current weather-based estimate: 331 MPN. Latest lab result was 1439 MPN on Sep 28, 2023.
Site snapshot
East River, Hermon A. MacNeil Park
East River
High contamination levels
Use the estimate and chart together to see whether rain usually lines up with elevated or high contamination levels here.
Middle lab-measured result across the site's full imported history.
Highest lab-measured bacteria level in the imported record for this site.
How to read this site
Enterococcus is a group of bacteria that normally lives in the intestines of people and animals. When it shows up at higher levels in the water, it can be a sign that sewage or other fecal contamination has reached that area.
It is used as an indicator organism, which means it helps flag the chance of sewage-related contamination without measuring every harmful thing directly. That makes it a useful way to track bacteria-based water quality conditions across many sites over time.
Lower numbers usually mean cleaner conditions for recreation. Higher numbers suggest elevated or high contamination levels, especially after rain.
MPN stands for Most Probable Number, a standard lab estimate of how much bacteria is present in a water sample. On this site, 35 MPN / 100 mL is the main reference point used to compare lower contamination levels with elevated results.
This is still only one part of water quality. These readings do not measure every form of pollution, and a single sample only captures one moment in time.
Today, based on recent rain
Best guess for the water right now
Likely high contamination levels
Rain sometimes matters here, but the pattern is weaker than at the most rain-sensitive sites.
Estimated bacteria level331 MPN
This estimate blends recent rain with the site's history. Below 35 MPN / 100 mL is the site's main cutoff for lower contamination levels during swimming or wading.
Threshold35
Estimate331
035140+
Based on past samples taken in similar wet-versus-dry conditions.
Most recent rain near this site.
This is the main rain window used in the estimate.
No current water temperature feed for this site.
Historical trend
Bacteria level and rain on sampling days
Jun 2022 to Sep 2023
High contamination levels are common here, especially when sampling followed rain.
Lower is better. Colored bands show lower, elevated, and high contamination levels, and blue bars show rain on that sampling day.