How it works
Every California tax auction,
enriched and analyzed.
Tax-defaulted property auctions are one of the last places serious investors can find value — but the data is buried across 58 county sites and stripped to the bare minimum. Trelys does the aggregating, enriching, and analysis for you.
We aggregate every county auction
California’s tax-defaulted property sales are scattered across 58 separate county sites, each publishing bare lists in its own format. Trelys pulls them into one place as each county’s auction schedule is released — minimum bids, opening and closing dates, and parcel numbers.
We enrich each parcel with public data
A bare APN and a minimum bid isn’t enough to make a decision. We match every parcel to public county assessor and GIS records — pulling map coordinates, situs address, land use, zoning and assessed values. Coverage varies by county and we show which fields a county actually publishes rather than implying we hold them all. Most tax-defaulted parcels are bare land, so building details are rarely on the roll at all.
You search, map, and dig in
Browse every active auction in one dashboard — opening bid, date, county, assessed value and risk findings, with bid and date filters, the interactive map, and a full detail page for any parcel: address, assessment, land use, zoning, and links out to the county and Google Maps. All of it is open from the first day of the 14-day free trial.
You model the deal
Run the numbers before you bid. The built-in ROI calculator models Fix & Flip, Buy & Hold, and BRRR strategies — pre-loaded with a property’s minimum bid and assessed value — and saves your analysis to the property so it’s there when you come back.
What you get
One dashboard, everything you need to bid.
Live auction listings
Minimum bids and auction dates across every active California county auction.
Enriched property data
Assessed values, land use, zoning, and building details sourced from county records.
Interactive mapping
Every geocoded parcel plotted so you can see where the deals actually are.
ROI analysis
Flip, rent, and BRRR modeling built in — no spreadsheets required.
Save & organize
Bookmark properties and keep your deal analysis attached to each one.
CSV export
Pull any filtered list of listings out for your own workflow.
Where the data comes from
Every listing is sourced directly from county treasurer and tax-collector auction schedules. Enrichment is pulled from public county assessor rolls and GIS parcel services. Coverage and depth vary by county — we’re transparent about what each one provides, and we expand as new counties publish their sales.
County tax collectors
Auction schedules, minimum bids
Assessor rolls
Assessed values, characteristics
County GIS
Coordinates, land use, zoning
Start today
See the next auction before the competition.
One plan, $29/month, with a 14-day free trial. Full access to every county auction and the tools to analyze them.