Howard County Times

Toxic algal blooms detected in Howard County’s Triadelphia Reservoir

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A high concentration of blue-green algae has been detected in Triadelphia Reservoir, the Washington Suburban Sanitary Commission said Thursday.

Blue-green algae, a type of algal bloom, can produce harmful chemicals called cyanotoxins that can cause severe illness in humans and animals if consumed or touched. Drinking water filtered from Triadelphia Reservoir, located along the Patuxent River in Howard and Montgomery counties, is not affected by the toxic bloom.


People who visit the reservoir for recreational activities, such as hiking, fishing and boating, should avoid touching or drinking the water directly. Pets should also not swim or drink the water, which is already prohibited by Washington Suburban Sanitary Commission’s regulations. The commission is closely monitoring water quality at its Patuxent Water Filtration Plant.

The commission advises people who come into contact with the affected water to rinse off with clean water. They should not eat organs from fish caught at the reservoir.


Those who do touch or ingest the water should call the following health departments:

  • Montgomery County: 240-777-0311 (Montgomery County 311)
  • Prince George’s County: 301-883-4748 (Prince George’s County 311)
  • Howard County: 410-313-1773 (Community Hygiene Department)