Volunteers sample on Sunday mornings, May through November. In teams of three, they generally start at 5:30 am and work for 3 hours. Each team works at one of these sites:
Assabet River, Westborough to Marlborough
Assabet River, Berlin to Hudson
Assabet River, Acton to Concord
Sudbury River, Framingham to Concord
Concord River, Concord to Lowell
Learn more about our water quality monitoring program.