Every real estate investor I know complains about the same thing: data is expensive and the cheap alternatives are garbage. CoStar wants $800/month. PropStream is $100/month for data that's six months stale. Reonomy is somehow worse than it sounds.
Meanwhile, counties are literally publishing the same underlying data for free. It's just buried in portals designed by government contractors in 2009 and nobody's bothered to extract it properly.
I've spent a lot of time pulling property data programmatically -- originally for lead gen tools, now for a few investor clients who'd rather pay for clean data than wrestle with county websites. Here's what's actually worth your time.
County Property Tax Records
This is the big one. Property tax assessor records are public in almost every county in the US. They include:
- Owner name and mailing address
- Assessed land value and improvement value
- Legal description and parcel ID
- Exemptions (homestead, senior, agricultural -- tells you a lot about the owner)
- Last sale date and price (in many counties)
- Improvement details: square footage, year built, bed/bath count
For real estate analysis, assessed value isn't the same as market value, but the ratio of assessed-to-market tells you a lot. Counties with 70% assessment ratios and recent comps you can pull from public records? That's the math you want to do.
Dallas County publishes a genuinely good property tax database. I built a scraper for it -- Dallas County property tax records -- that lets you search by owner name, address, or parcel ID and get structured output. Useful if you're farming a specific area or want to pull all properties owned by a particular entity (LLCs, trusts, etc.).
The LLC angle is underrated. A lot of distressed sellers own properties through shell entities. Being able to search by entity name and pull all their holdings in a county -- without paying $50/search to a skip tracing service -- is legitimately valuable.
Building Permits
Building permit data is one of the most underused sources in real estate. Here's what it actually tells you:
For investors: Active permits on a property mean someone's doing work. Unpermitted work on a property you're buying is a liability. Permit history tells you when renovations happened and whether they were done properly.
For contractors and agents: New permit pulls are leads. A homeowner who just pulled an ADU permit is probably talking to contractors. A builder who pulls 20+ permits a year is a serious player worth knowing.
Most cities and counties file permits with state or local databases. I pull from a dataset that aggregates permit activity across jurisdictions -- building permits and construction leads. You can filter by permit type, jurisdiction, date range, and value. The output includes applicant contact info in many cases, which is the lead-gen angle.
Honestly the permit data is one of those things that sounds niche until you use it and then you can't believe you were doing market research without it.
Contractor and Agent Leads via Business Directories
This one's more distribution than analysis, but bear with me.
If you're doing BRRRR deals or flips, your biggest operational bottleneck is usually contractor capacity. Good GCs are hard to find and they're always booked. Most investors find contractors through word of mouth, which is slow and regionally limited.
YellowPages still has reasonably good business data for licensed contractors -- electrical, plumbing, HVAC, general contracting. More importantly, it has phone numbers and addresses that are often more current than what you'll find through state licensing boards.
YellowPages scraper lets you pull contractor listings by category and geography. I've used it to build targeted outreach lists for markets I'm entering where I don't have existing relationships. Filter by rating, pull the top 30 GCs in a metro, start making calls. Not glamorous but it works.
Same approach applies to finding buyer's agents, property managers, and wholesalers in new markets.
How to Combine These Sources
The workflow I actually use:
- Pull property tax records for a target zip code or owner type (filter for out-of-state owners -- higher distress probability)
- Cross-reference with permit history to flag properties with unpermitted work or no renovation in 20+ years
- Skip trace owner contact info (I use a separate service for this part)
- Route high-probability leads to outreach
The key insight is that county data is dirty and you need to combine sources to get signal. A property with an out-of-state owner, no permits in 15 years, and a high assessed-to-market-value ratio is interesting. Any single one of those data points alone isn't enough.
What You're Actually Paying For With the Expensive Tools
CoStar, PropStream, etc. aren't selling you data you can't get elsewhere. They're selling you:
- Aggregation across all counties in one interface
- Data that's been cleaned and deduplicated
- MLS comps (which are genuinely not available publicly)
- Time
If your deal volume justifies $800/month for CoStar, great. But if you're doing 2-4 deals a year and paying for a monthly subscription to look up properties occasionally, you're probably overpaying for convenience you don't need.
The public sources I described above cover about 70% of what you'd use PropStream for. The remaining 30% -- mostly MLS comps and automated valuation models -- you can often get from a friendly agent who runs comps for you in exchange for referrals.
Not every tool has to be a subscription.
All three scrapers I mentioned are on my Apify profile. They're pay-per-run so you're only paying when you actually use them -- which fits better with deal-by-deal research than a monthly flat fee. Each has a free trial run if you want to test with real data first.
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