Long Island water quality

Weekly report on measurements taken at 29 locations off the shores of Nassau and Suffolk.

The Gobler Laboratory, part of the School of Marine and Atmospheric Sciences at Stony Brook University, measures water quality and issues a weekly report covering conditions at 29 sites on Long Island.

Here are the most recent measures. The lab records the amount of dissolved oxygen (mg/L), fecal coliform bacteria (per 100 ml), chlorophyll A (in micrograms per liter), harmful algae and water clarity (in meters) and compares the values with state and federal guidelines to come up with an overall score for water quality, which is then categorized as "good," "fair" or "poor."

The lab advises that the water quality data is for informational purposes and urges users to "check with the county health departments and NYSDEC for details on where swimming and shellfishing is permitted." You can read more about the water quality testing here. This database was updated on July 11, 2019.

Water quality at 29 locations

  • Good
  • Fair
  • Poor

Location

Water quality

Clear Search
Location Water quality Impairments Minimum disolved oxygen Clarity Fecal coliform Chlorophyll Harmful Algae Overall score
Location Hempstead Harbor Water quality Poor Impairments Harmful algal bloom, water clarity, fecal coliform, low dissolved oxygen Minimum disolved oxygen 3.74 Clarity 1.10 Fecal coliform 94 Chlorophyll 26.44 Harmful Algae Prorocentrum 10^3 cells/mL, Scrippsiella 10^3 cells/mL Overall score 1.60
Location Oyster Bay Harbor Water quality Good Impairments None Minimum disolved oxygen 4.09 Clarity 1.43 Fecal coliform 0 Chlorophyll 4.27 Harmful Algae Overall score 2.60
Location Cold Spring Harbor Water quality Good Impairments None Minimum disolved oxygen 5.28 Clarity 1.50 Fecal coliform 20 Chlorophyll 11.94 Harmful Algae Overall score 2.40
Location Huntington Harbor Water quality Fair Impairments Low dissolved oxygen, algal bloom, fecal coliform, water clarity Minimum disolved oxygen 2.45 Clarity 1.85 Fecal coliform 50 Chlorophyll 12.65 Harmful Algae Overall score 2.20
Location Northport Harbor Water quality Poor Impairments Harmful algal bloom, water clarity, fecal coliform, low dissolved oxygen Minimum disolved oxygen 3.49 Clarity 1.22 Fecal coliform 72 Chlorophyll 25.67 Harmful Algae Dinophysis 10^4 cells/L Overall score 1.60
Location Stony Brook Harbor Water quality Good Impairments None Minimum disolved oxygen 4.96 Clarity 1.10 Fecal coliform 48 Chlorophyll 4.62 Harmful Algae Overall score 2.60
Location Port Jefferson Harbor Water quality Fair Impairments Low dissolved oxygen, fecal coliform, water clarity, algal bloom Minimum disolved oxygen 4.10 Clarity 1.80 Fecal coliform 44 Chlorophyll 5.14 Harmful Algae Overall score 2.20
Location Mount Sinai Harbor Water quality Good Impairments None Minimum disolved oxygen 3.88 Clarity 2.20 Fecal coliform 16 Chlorophyll 7.31 Harmful Algae Overall score 2.40
Location Hewlett Bay Water quality Fair Impairments Algal bloom, water clarity, low dissolved oxygen, fecal coliform Minimum disolved oxygen 4.00 Clarity 1.40 Fecal coliform 14 Chlorophyll 7.23 Harmful Algae Overall score 2.20
Location Middle Bay Water quality Good Impairments None Minimum disolved oxygen 2.92 Clarity 1.20 Fecal coliform 4 Chlorophyll 10.37 Harmful Algae Overall score 2.40
Location South Oyster Bay Water quality Good Impairments None Minimum disolved oxygen 3.70 Clarity 0.50 Fecal coliform 6 Chlorophyll 13.18 Harmful Algae Overall score 2.50
Location Fire Island Inlet Water quality Good Impairments None Minimum disolved oxygen 3.60 Clarity 2.60 Fecal coliform 10 Chlorophyll 6.85 Harmful Algae Overall score 2.60
Location Western Great South Bay Water quality Good Impairments None Minimum disolved oxygen 6.50 Clarity 0.40 Fecal coliform 14 Chlorophyll 18.92 Harmful Algae Overall score 2.50
Location Central Great South Bay Water quality Fair Impairments Low dissolved oxygen, algal bloom, fecal coliform Minimum disolved oxygen 1.60 Clarity 0.85 Fecal coliform 66 Chlorophyll 12.65 Harmful Algae Overall score 2.00
Location Eastern Great South Bay Water quality Fair Impairments Water clarity, low dissolved oxygen, fecal coliform, algal bloom Minimum disolved oxygen 2.26 Clarity 0.90 Fecal coliform 140 Chlorophyll 13.48 Harmful Algae Overall score 2.00
Location Forge River Water quality Poor Impairments Harmful algal bloom, low dissolved oxygen, water clarity, fecal coliform Minimum disolved oxygen 0.00 Clarity 0.20 Fecal coliform 98 Chlorophyll 69.27 Harmful Algae Gymnodinium 10^4 cells/mL; Prorocentrum, Scrippsiella, Polykrikos 10^3 cells/mL Overall score 1.20
Location Central Moriches Bay Water quality Poor Impairments Harmful algal bloom, low dissolved oxygen, water clarity, fecal coliform Minimum disolved oxygen 0.00 Clarity 0.45 Fecal coliform 18 Chlorophyll 124.15 Harmful Algae Gymnodinium 10^4 cells/mL, Prorocentrum 10^3 cells/mL Overall score 1.20
Location Eastern Moriches Bay Water quality Poor Impairments Algal bloom, low dissolved oxygen, water clarity, fecal coliform Minimum disolved oxygen 0.00 Clarity 0.80 Fecal coliform 36 Chlorophyll 23.28 Harmful Algae Overall score 1.60
Location Quantuck Bay Water quality Fair Impairments Algal bloom, low dissolved oxygen, water clarity Minimum disolved oxygen 1.57 Clarity 0.90 Fecal coliform 12 Chlorophyll 26.30 Harmful Algae Overall score 1.80
Location Western Shinnecock Bay Water quality Fair Impairments Low dissolved oxygen, algal bloom, fecal coliform Minimum disolved oxygen 0.46 Clarity 1.00 Fecal coliform 0 Chlorophyll 13.68 Harmful Algae Overall score 2.20
Location mid-Shinnecock Bay Water quality Good Impairments None Minimum disolved oxygen 2.36 Clarity 1.30 Fecal coliform 0 Chlorophyll 2.09 Harmful Algae Overall score 2.80
Location Shinnecock Inlet Water quality Good Impairments None Minimum disolved oxygen 6.63 Clarity 1.80 Fecal coliform 0 Chlorophyll 2.57 Harmful Algae Overall score 3.00
Location Mattituck Inlet Water quality Fair Impairments Algal bloom, water clarity, fecal coliform Minimum disolved oxygen 5.17 Clarity 0.80 Fecal coliform 18 Chlorophyll 24.39 Harmful Algae Overall score 2.00
Location Little Peconic Bay Water quality Good Impairments None Minimum disolved oxygen 4.48 Clarity 1.20 Fecal coliform 4 Chlorophyll 7.60 Harmful Algae Overall score 2.40
Location Western Flanders Bay Water quality Poor Impairments Harmful algal bloom, low dissolved oxygen, water clarity, fecal coliform Minimum disolved oxygen 1.02 Clarity 0.60 Fecal coliform 28 Chlorophyll 25.38 Harmful Algae Gymnodinium 10^2 cells/mL; Peridiniun, Scrippsiella, Kryptoperidinium, Prorocentrum, Akashiwo 10^3 cells/mL Overall score 1.40
Location Peconic River Water quality Fair Impairments Low dissolved oxygen, water clarity, fecal coliform, algal bloom Minimum disolved oxygen 0.00 Clarity 0.70 Fecal coliform 104 Chlorophyll 7.04 Harmful Algae Overall score 1.80
Location Great Peconic Bay Water quality Good Impairments None Minimum disolved oxygen 5.08 Clarity 1.30 Fecal coliform 0 Chlorophyll 6.70 Harmful Algae Overall score 2.60
Location Sag Harbor Water quality Fair Impairments Algal bloom, water clarity, low dissolved oxygen, fecal coliform Minimum disolved oxygen 4.63 Clarity 1.50 Fecal coliform 14 Chlorophyll 9.70 Harmful Algae Overall score 2.20
Location Three Mile Harbor Water quality Good Impairments None Minimum disolved oxygen 2.66 Clarity 2.10 Fecal coliform 2 Chlorophyll 7.04 Harmful Algae Overall score 2.60

Please choose a filter above to display results or

DISPLAY ALL

No results for your selection

RESET
BACK TO TOP

Comments

We're revamping our Comments section. Learn more and share your input.