Erckenbrack Park
Tested by San Mateo County, usually every 7 days.
Taken 25 days ago. Results can take 1 to 3 weeks to be published, and many sites are tested less often in winter.
Every bacteria in this test: Total coliform 2,046 · E. coli 238 · Enterococcus 62. The grade follows the worst one against its own limit.
Grade C over 5 tests from Sep 21, 2026 to Oct 19, 2026. 2 were over the limit.
Passed, but close to the limit
The latest test was under the safe limit. Avoid swallowing water, keep cuts covered, and stay out for 72 hours after any rain.
Enterococcus over time
- Monday, Oct 19, 2026Total coliform 2,046 · E. coli 238 · Enterococcus 62
- Tuesday, Oct 13, 2026Total coliform 650 · E. coli 63 · Enterococcus 20
- Monday, Oct 5, 2026Total coliform 2,359 · E. coli 233 · Enterococcus 148
- Monday, Sep 28, 2026Total coliform 1,430 · E. coli 231 · Enterococcus 156
- Monday, Sep 21, 2026Total coliform 1,058 · E. coli 175 · Enterococcus 41
- Monday, Sep 14, 2026Total coliform 1,333 · E. coli 279 · Enterococcus 30
- Tuesday, Sep 8, 2026Total coliform 2,282 · E. coli 368 · Enterococcus 52
- Monday, Aug 31, 2026Total coliform 2,187 · E. coli 377 · Enterococcus 388
- Monday, Aug 24, 2026Total coliform 3,282 · E. coli 959 · Enterococcus 504
- Monday, Aug 17, 2026Total coliform 4,352 · E. coli 640 · Enterococcus 1,722
Enterococcus and coliform bacteria live in the guts of people and animals. Health departments test for them because they travel with sewage, runoff and animal waste, so a high count is a warning that germs that do make people sick are likely in the water too. Clear water can still be contaminated: bacteria and viruses are too small to see.
San Diego County's DNA test (ddPCR) counts bacterial DNA instead of growing the bacteria in a lab, so it returns results the same day. Its numbers run higher than the older lab tests, which is why its safe limit is 1,413 rather than 104. The two are never compared on this page.
San Diego County's health department says swimming in water under an advisory can cause stomach illness, such as diarrhea and vomiting, and skin and ear infections. The EPA's national swimming guidelines are set at a level where about 32 to 36 of every 1,000 swimmers would get a stomach illness. A study of San Diego surfers found about 12 extra stomach-illness cases per 1,000 in wet weather, highest during rain and the day after, and back near normal 3 days later.
The grade is Nautical Nick's, built on the official limits: A is a quarter of the limit or less, B half or less, C under the limit, D over it, and F more than 10 times over. When a county posts an advisory or closes a beach, its sign is the final word.
Sources: California State Water Board beach test results; San Diego County Department of Environmental Health sample reports; Surfrider Foundation Blue Water Task Force; National Weather Service daily rain totals via the Iowa Environmental Mesonet (Hayward Air Term, Oakland, San Francisco Downtown, San Francisco Intl). Limits: California Code of Regulations, Title 17, Section 7958.