Open advisory in source
Clear Lake · north drive
Lake · 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
Live source fallback: Live DataStore query failed (409). Showing the verified daily snapshot instead.
Open advisory in source
Lake Berryessa · Putah Canyon campground
Napa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
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.
No recent evidence
San Joaquin-Sacramento River · Riverview Park near New York Point
Contra Costa · Harmful algae report
No recent bacteria result or active advisory was found near this spot.
Open advisory in source
Kiteboard Beach, San Mateo
Kiteboard Beach · BeachWatch
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lakeshore Park, San Mateo
Lakeshore Park Rec Center · BeachWatch
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Aquatic Park, San Mateo
Aquatic Park · BeachWatch
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Dillon Beach, Marin
DILLON · BeachWatch
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Miramar Reservoir
San Diego · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake of the Pines · lake-wide
Nevada · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
North Yuba River · Carlton Campground, California
Yuba · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake Oroville Middle Fork · upstream of Bean Creek
Butte · 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.
Using the verified fallback snapshotConnection checked: Oct 23, 2026, 4:07 PM PDTNewest state source update: Oct 8, 2026, 10:55 AM 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.