Open advisory in source
Clear Lake · Buckingham Park
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
Bloom under review
Lake Berryessa · Putah Canyon campground
Napa · Harmful algae report
Use extra caution. Avoid visible scum, foam, or discolored water.
Bloom under review
Trout Creek · Lake Tahoe Community College
El Dorado · Harmful algae report
Use extra caution. Avoid visible scum, foam, or discolored water.
Bloom under review
San Joaquin-Sacramento River · Riverview Park near New York Point
Contra Costa · Harmful algae report
Use extra caution. Avoid visible scum, foam, or discolored water.
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
Delta Coves · North
Contra Costa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Hume lake · Sequoia National Forest
Fresno · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Discovery Bay Marina · Bar and Grill
Contra Costa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Martinez Shoreline · Radke Martinez Regional Shoreline Park
Contra Costa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Lake Hacienda · Highway 178 /mirmonte drive
Kern · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Discovery Bay · Carillo Bay
Contra Costa · Harmful algae report
The source record lists an advisory as open. Verify locally and avoid water contact until confirmed.
Open advisory in source
Carquinez Strait · Martinez Marina at Radke Martinez Regional Shoreline
Contra Costa · 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: Jul 28, 2026, 5:24 PM PDTNewest state source update: Jul 28, 2026, 5:07 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.