What bacteria levels represent
Enterococcus is used here as a warning sign for sewage-related contamination. Lower numbers usually mean cleaner conditions for recreation.
NYC Water Check
How clean is NYC water right now?
Track bacteria-based water quality conditions across NYC waterways, with current readings and historical trends.
Data courtesy of Billion Oyster Project. This tool tracks bacteria-based contamination levels, not every form of pollution.
Current snapshot
A quick read on recent bacteria-based water quality conditions across sampled NYC shorelines.
- Latest update
- Oct 2, 2025
- Sites currently sampled
- 99
- Lower contamination levels
- 50
- Elevated or high contamination levels
- 27
- Historic sites in the record
- 57
- Total samples
- 14,812
Start here
What this site shows
NYC Water Check helps you understand current bacteria levels across NYC waterways, compare places, and see how conditions change over time.
Current conditions
Check the latest bacteria reading at each shoreline site and see how it compares to typical levels.
Map-based exploration
Start with the place you care about most, whether that is the East River, Hudson, or a nearby shoreline.
Trends and context
See how readings shift over time and why rainy weather often pushes bacteria levels higher.
This is a public-facing water quality tool, not a full harbor-health dashboard. It focuses on bacteria-based contamination indicators tied to sewage-related conditions.
Trends over time
See how bacteria-based water quality changes across the city
These charts show whether conditions are staying close to typical levels or moving higher across sampled NYC waterways. Rainfall matters, so it helps explain why conditions can change quickly.
What bacteria levels mean
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.
- Lower contamination levels
- 65%
- Sites sampled
- 77
- Median bacteria level
- 20 MPN
- Day-of rainfall
- 0.00 in
Read this as a citywide bacteria indicator, not a full water quality score. Weeks with broader site coverage are more representative, and citywide values are only shown when at least 7 sites reported.
Across the boroughs
How do bacteria levels compare around NYC?
This view compares long-term shoreline conditions across the five boroughs. It uses the share of samples with lower contamination levels, which is easier to read than a single citywide score.
Start with a shoreline
Good places to begin exploring
These sites pair current readings with longer records, so they are useful starting points for understanding both today's conditions and longer-term patterns.
Lower contamination levels
Wallabout Channel (Brooklyn Navy Yard)
East River · Brooklyn Navy Yard · Brooklyn
- Latest bacteria
- 10 MPN
- Lab sample
- Oct 2, 2025
- Records
- 298
Lower contamination levels
Hudson River, Pier 40
Hudson River · West Village · Manhattan
- Latest bacteria
- <10 MPN
- Lab sample
- Oct 2, 2025
- Records
- 271
Lower contamination levels
East River, Dumbo Cove
East River · Dumbo · Brooklyn
- Latest bacteria
- 10 MPN
- Lab sample
- Oct 2, 2025
- Records
- 258
Lower contamination levels
Hudson River, Pier 66
Hudson River · Hudson Yards · Manhattan
- Latest bacteria
- <10 MPN
- Lab sample
- Oct 2, 2025
- Records
- 254
Lower contamination levels
Hudson River, Pier 26
Hudson River · Tribeca · Manhattan
- Latest bacteria
- <10 MPN
- Lab sample
- Oct 2, 2025
- Records
- 248
High contamination levels
Hudson River, Pier 84
Hudson River · Hell's Kitchen · Manhattan
- Latest bacteria
- 341 MPN
- Lab sample
- Oct 2, 2025
- Records
- 241
Lower contamination levels
East River, Brooklyn Bridge Beach (Manhattan)
East River · Seaport · Manhattan
- Latest bacteria
- 20 MPN
- Lab sample
- Oct 2, 2025
- Records
- 237
High contamination levels
Gowanus Canal, Second Street Sponge Park
Gowanus Canal · Gowanus · Brooklyn
- Latest bacteria
- 3448 MPN
- Lab sample
- Oct 2, 2025
- Records
- 232
How to read NYC water quality
Why bacteria levels matter, and why they change
This site tracks bacteria-based water quality conditions using public shoreline sampling data. It is meant to help people understand what current readings show, what is typical, and what weather patterns often change.
Why they matter
A single reading does not tell the whole story, but repeated sampling helps show where bacteria levels are usually lower and where they tend to rise.
Why conditions change
Conditions often worsen after rainfall because stormwater and sewer overflows can wash more contamination into nearby waterways.
Data courtesy of Billion Oyster Project. The site reorganizes that public sampling record into a simpler tool for checking current conditions and historical trends.