Open advisory in source
Trout Creek · Lake Tahoe Community College
El Dorado · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Before You DipIndependent public-data project
California water, made clearer
Know what the water knows
before you dip.
Recent bacteria results and harmful-algae reports, brought together for people and their dogs.
Not an official government service. Always follow signs and local advisories.
Who is getting wet?
One shoreline. Different risks.
Human guidance compares recent fecal-indicator bacteria results and posted algae advisories.
Current evidence finder
Latest statewide reports
Open advisory in source
Wildcat Creek · Tilden Regional Park
Alameda · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Kern River
Kern · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake Britton
Shasta · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Harveston Lake · lake-wide
Riverside · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Prado Reservoir · lake-wide
San Bernardino · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Putah Creek · ~0.75 mi upstream of confluence with Dry Creek (512PCD001)
Lake · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Mountain Meadows Reservoir · Dam
Lassen · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Big bear lake ca · Lighthouse observatory
San Bernardino · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Bell Canyon Reservoir
Napa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake Tulloch · Green Springs Arm
Tuolumne · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake Tulloch · Cove north of Kiva Swim Area
Calaveras · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
What this tool does
Two public datasets.
One honest answer.
Before You Dip does not invent a safety score. It shows the newest available evidence, its age, and why a status appears.
Find nearby evidence
Search official monitoring stations and match nearby freshwater bloom reports.
Keep the caveats
Results older than 45 days become “unknown.” Missing reports never become a green light.
Explain the signal
Every status opens to the measurements, dates, comparison lines, and source links behind it.
The public-data ledger
See where every signal comes from.
The app discovers the current resources through California’s CKAN API and queries the live DataStore when the page loads and whenever you search. No API key is required.
Connected to the live state DataStoreConnection checked: Sep 7, 2026, 6:07 PM PDTNewest state source update: Sep 4, 2026, 5:29 PM PDT
“Live” means this app checked the newest data currently published by the source. It cannot make sampling or agency publication happen sooner. Always use posted signs and local advisories for the final decision.