Water Quality Test Results

Ocean Monitoring

Humboldt County is funded by the U.S. Environmental Protection Agency Beach Environmental Assessment and Coastal Health Act (BEACH Act) to monitor for the presence of bacteria in ocean water areas. Water samples are taken near creek mouths that deliver stormwater into the ocean.

Current Results

Beach monitoring has ended and will resume April 2018.
Water quality test results by location and date.
Locations Resample Sample  Date 
E.Coli Exceeds
Enterococcus Exceeds
Moonstone Beach Yes 11/1/2017 1,597
No 20 No 62 No
Clam Beach County Park No 10/30/2017 2,495 No 31 No 30
Luffenholtz Creek No 10/30/2017 677
No 20 No 20 No
Moonstone Beach No 10/30/2017 3,255
No 216
No 110 Yes
North Mad River Mouth No 10/30/2017 332 No 31 No
10 No
Trinidad State Park / Mill Creek No 10/30/2017 2,014 No 10 No 10 No
Previous results are available for download (XLS).


All units are in are in MPN/100 ml. MPN = "most probable number".
State water quality standards for bacteria in recreational waters are not to exceed:
Total coliform = 10,000 MPN/100ml
E. coli (a fecal coliform) = 400 MPN/100 ml
Enterococcus (E. faecalis) = 104 MPN/100 ml
*Fecal coliform to total coliform ratio exceeds 0.1, and the total coliform count exceeds 1,000 MPN