On May 21st, 2025, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, 0.04 inches of precipitation was recorded at TF Green. Overall bacteria counts were lower than during the previous sampling event.
Fecal coliform counts were lower in the Seekonk River, compared to the Providence River (geometric mean of 37 MPN/100 mL for the Seekonk River compared to 45 MPN/100mL for the Providence River) for sampling conducted on May 21st. The maximum count (2,300 MPN/100 mL) was measured at the Point Street Bridge sampling location.
Fecal coliform counts were lower in the Providence River, compared to the previous sampling on May 7th (geometric mean of 45 MPN/100 mL compared to 369 MPN/100 mL on 5/7). Fecal coliform counts were lower in the Seekonk River, compared to the previous sampling on May 7th (geometric mean of 37 MPN/100 mL compared to 1121 MPN/100 mL on 5/7).
Enterococci results had an overall geometric mean of 16 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 74 MPN/100 mL at Point St Bridge.
The next scheduled sampling date is June 4th.
The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.
Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing
| | Fecal Coliform | Enterococci |
| Primary Contact1 | Geometric mean ≤50 MPN/100 mL <10% of samples >400 MPN/100 mL | Geometric mean ≤35 colonies/100 mL All samples ≤104 colonies/100 mL2 |
| Shellfishing | Geometric mean ≤14 MPN/100 mL <10% of samples >49 MPN/100 mL3 | NO ENTEROCOCCI CRITERIA |
1Fecal coliform primary contact criteria applied only when adequate enterococci data are not available; 2Single sample maximum criterion for determining beach swimming advisories at designated beaches as evaluated by the Rhode Island Department of Health; 3For a three-tube decimal dilution.
Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.