North Roosevelt Creek
Tested by San Mateo County, usually every 9 days.
Taken 66 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 over 24,196 · E. coli 1,112. The grade follows the worst one against its own limit.
No recent test
The last test here was 66 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.
Likely runoff from a creek or drain
This test is taken near a creek, lagoon or drain mouth. Runoff from land reaches the ocean here, and drains like these can flow even in dry weather.
Total coliform over time
- Tuesday, Sep 8, 2026Total coliform over 24,196 · E. coli 1,112
- Monday, Apr 27, 2026Total coliform 11,199 · E. coli 41
- Monday, Apr 20, 2026Total coliform 24,196 · E. coli 300.74 in of rain in the 3 days before
- Monday, Apr 13, 2026Total coliform over 24,196 · E. coli 1851.93 in of rain in the 3 days before
- Wednesday, Apr 1, 2026Total coliform over 24,196 · E. coli 2410.30 in of rain in the 3 days before
- Monday, Mar 23, 2026Total coliform over 24,196 · E. coli 121
- Monday, Mar 16, 2026Total coliform over 24,196 · E. coli 31
- Monday, Mar 9, 2026Total coliform 24,196 · E. coli 50
- Monday, Mar 2, 2026Total coliform 120 · Enterococcus over 24,196
- Monday, Feb 23, 2026Total coliform 8,164 · E. coli 20
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 (San Francisco Downtown, San Francisco Intl). Limits: California Code of Regulations, Title 17, Section 7958.