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Home/Water Quality/Los Angeles County
Water quality testing site · Los Angeles County

Near Pena Creek at Las Tunas County Beach

Tested by Los Angeles County, usually every 10 days.

A
Latest test · Tuesday, Jul 21, 2026
Water quality A: Clean

Taken 115 days ago. Results can take 1 to 3 weeks to be published, and many sites are tested less often in winter.

Enterococcus
under 10
per 100 mL
Safe limit
104
This test was 10% of the limit.
Usual here
10
The middle of 22 tests over the past year. This test is about normal for this beach.

Every bacteria in this test: Total coliform 41 · E. coli 20 · Enterococcus under 10. The grade follows the worst one against its own limit.

A
Last 30 days

Grade A over 4 tests from Jul 4, 2026 to Jul 21, 2026. None were over the limit.

Can I go in?

No recent test

The last test here was 115 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.

History

Enterococcus over time

10100200Usual here: 10Safe limit: 104Friday, Dec 26, 2025: 0.49 in of rainSunday, Apr 12, 2026: 0.20 in of rainWednesday, Dec 31, 2025: 0.42 in of rainTuesday, Feb 17, 2026: 0.41 in of rainThursday, Jan 1, 2026: 1.08 in of rainSunday, Jan 4, 2026: 0.32 in of rainWednesday, Feb 18, 2026: 0.22 in of rainMonday, Nov 17, 2025: 0.83 in of rainTuesday, Mar 31, 2026: 0.17 in of rainSunday, Sep 6, 2026: 1.00 in of rainFriday, Jan 2, 2026: 0.26 in of rainWednesday, Oct 21, 2026: 0.34 in of rainWednesday, Feb 11, 2026: 0.54 in of rainWednesday, Dec 24, 2025: 2.65 in of rainSaturday, Jan 3, 2026: 0.28 in of rainThursday, Nov 20, 2025: 0.60 in of rainSunday, Nov 1, 2026: 0.26 in of rainSaturday, Oct 31, 2026: 0.19 in of rainThursday, Feb 19, 2026: 0.42 in of rainFriday, Nov 21, 2025: 0.48 in of rainTuesday, Oct 14, 2025: 1.58 in of rainSunday, Nov 16, 2025: 0.26 in of rainFriday, Nov 14, 2025: 0.80 in of rainTuesday, Feb 10, 2026: 0.19 in of rainMonday, Feb 16, 2026: 1.60 in of rainSaturday, Nov 15, 2025: 1.45 in of rainAugOctDecFebAprJunAugOct
Rain of 0.2 in or more at the nearest airportsHover or tap a dot for its date and reading
Recent tests
  • A
    Tuesday, Jul 21, 2026
    Total coliform 41 · E. coli 20 · Enterococcus under 10
  • A
    Saturday, Jul 18, 2026
    Total coliform 140 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Jul 7, 2026
    Total coliform under 10 · E. coli under 10 · Enterococcus under 10
  • A
    Saturday, Jul 4, 2026
    Total coliform 30 · E. coli 20 · Enterococcus under 10
  • A
    Friday, Jun 19, 2026
    Total coliform 10 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Jun 9, 2026
    Total coliform under 1 · E. coli under 1 · Enterococcus under 10
  • A
    Tuesday, Jun 2, 2026
    Total coliform 270 · E. coli 20 · Enterococcus 10
  • A
    Tuesday, May 26, 2026
    Total coliform 31 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, May 19, 2026
    Total coliform 660 · E. coli 200 · Enterococcus 20
  • A
    Tuesday, May 12, 2026
    Total coliform 51 · E. coli 10 · Enterococcus 10
What the numbers mean

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 (Burbank/Glendale, Los Angeles Intl). Limits: California Code of Regulations, Title 17, Section 7958.