Crown Beach (Alameda Co): Crab Cove
Tested by East Bay Regional Park District, usually every 7 days.
Taken 39 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: Fecal coliform 550 · Total coliform 1,000 · Enterococcus 120. The grade follows the worst one against its own limit.
Grade D over 6 tests from Sep 8, 2026 to Oct 5, 2026. 4 were over the limit.
No recent test
The last test here was 39 days ago, too long ago to say anything about the water today. Some sites are tested only in summer. Stay out for 72 hours after any rain of 0.2 in or more, and check the county's status before going in.
Cause not known
No significant rain fell in the 3 days before this test, and the testing agency does not name a cause.
Enterococcus over time
- Monday, Oct 5, 2026Fecal coliform 550 · Total coliform 1,000 · Enterococcus 120
- Monday, Sep 28, 2026Fecal coliform 800 · Total coliform 2,500 · Enterococcus 31
- Wednesday, Sep 23, 2026Fecal coliform 350 · Total coliform 770 · Enterococcus 31
- Monday, Sep 21, 2026Fecal coliform 2,000 · Total coliform 4,400 · Enterococcus 490
- Monday, Sep 14, 2026Fecal coliform 290 · Total coliform 1,300 · Enterococcus 10
- Tuesday, Sep 8, 2026Fecal coliform 16 · Total coliform 380 · E. coli 86 · Enterococcus 10
- Monday, Aug 31, 2026Fecal coliform 33 · Total coliform 170 · E. coli 41 · Enterococcus 23
- Wednesday, Aug 26, 2026Fecal coliform 100 · Total coliform 390 · E. coli 74 · Enterococcus 63
- Monday, Aug 24, 2026Fecal coliform 1,600 · Total coliform 3,300 · E. coli 2,300 · Enterococcus 21
- Monday, Aug 17, 2026Fecal coliform 4 · Total coliform 140 · E. coli 20 · Enterococcus 2
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 (Concord/Buchanan, Hayward Air Term, Oakland, San Francisco Downtown, San Francisco Intl). Limits: California Code of Regulations, Title 17, Section 7958.