2018 Bacteria Monitoring Data

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In 2018, Save the Sound collected and tested water quality from Greenwich, CT, through Westchester County, to Queens and into Nassau County. Samples were analyzed for the fecal indicator bacteria Enterococcus, which can affect human health. Explore the map above to see what we found. The colors reflect average bacteria levels which give a sense of how high the fecal contamination levels can get at each site. The “% Pass” and “% Fail” show how many samples passed or failed the single sample criteria for safe swimming in New York and Connecticut.

Summary of Findings

Overall increase in fecal bacteria

We are seeing an overall increase of pollution this year from 2017. Fecal contamination rates overall raised from 43% contaminated in 2017 to 51% contaminated in 2018.

Failure is based on EPA safe swimming criteria used in CT and NY to monitor and manage beaches*

Wet weather fueled higher failure rates

Wet weather is a factor in the increased fecal pollution in 2018. This year’s wet weather sampling events were similar to 2016 in frequency and failure rate; however, the total volume of precipitation was very different. 58% of wet weather sampling events in 2018 were over 1 inch of precipitation where 35% of wet weather sampling events in 2016 were over 1 inch of cumulative precipitation.

Above: Percentages of wet and dry weather passes and fails from 2016 – 2018 monitoring seasons. Failure is based on EPA safe swimming criteria used in CT and NY to monitor and manage beaches.*

Above: Percentages of wet weather samples with rainfall 1/2“ – 1“ and over 1“

Stormwater is a conduit of pollution, especially when it falls on impervious surfaces like pavement. It can also increase the underground flow and subsequent discharge of groundwater contaminated with untreated sewage leaking from sewer lines and septic systems. Large storm events can overburden compromised sewer lines causing sewage to erupt from manholes and pump stations before making it to treatment facilities.

Reducing stormwater runoff is one strategy for decreasing fecal contamination in our waterways. Save the Sound advocates for green infrastructure projects as well as fighting for proper operation and maintenance of aging and failing sewer infrastructure in our communities.

Rivers in the study remain the most polluted

Area streams, creeks, and rivers are still polluted and continue to carry that pollution to Long Island Sound. The fecal bacteria levels in these tributaries went up this year, from a 63% failure rate in 2017 to a 74% failure rate in 2018. These streams often run through residential areas and can pose a health hazard to communities. It is clear that this remains an area in need of attention!

Failure is based on EPA safe swimming criteria used in CT and NY to monitor and manage beaches*

Hutchinson River and Beaver Swamp Brook still alarmingly polluted

Beaver Swamp Brook is the second most polluted waterway in our study area behind the Hutchinson River.

Residents in the area have had enough and have started to mobilize to demand improvements in Beaver Swamp Brook water quality. The brook runs through multiple residential areas and along the border of Rye Neck High School before making its way into Mamaroneck Harbor in New York. Save the Sound is working with these residents and the managing authorities to root out the fecal contamination sources contaminating this waterway. Save the Sound submitted a recommendation this year, with supporting monitoring data, to the New York State Department of Environmental Conservation for listing this waterway on the New York State Impaired Waters List. Read more about this recommendation and what it entails here.

2018 Season Best and Worst

Ten Sites with the Lowest Fecal Contamination Levels (No Failing Samples)

Scores >104 are considered unsafe for swimming in marine water and > 61 are considered unsafe for freshwater.
Average (GeoMean) > 35 are considered unsafe for swimming in marine water and > 33 are considered unsafe in freshwater.

Ten Sites with the Highest Fecal Contamination Levels

Scores >104 are considered unsafe for swimming in marine water and > 61 are considered unsafe for freshwater. Average (GeoMean) > 35 are considered unsafe for swimming in marine water and > 33 are considered unsafe in freshwater.

Be a Part of the Solution

• ​Everyone can help reduce sewage pollution sources simply by conserving water, which will lessen the wear-and-tear on our water infrastructure and reduce sewage overflows by lowering the volume of water in the system.
• Homeowners need to repair the sewer lines that connect homes and businesses to municipal sewers, or maintain their septic systems.
• Dog owners should put pet waste in the trash, never in a catch basin or on the street.
• Every community and homeowner should work on strategies like creating rain gardens to help reduce runoff.
• If you see sewage overflowing in your community, please let us know by sending a photograph or video plus the time and location of the overflow to  pollution@savethesound.org.