10 red flags to watch for when underwriting a rental property
Before you buy, know what to look for. These red flags can turn a promising deal into a money pit.
Not every deal is a good deal. Experienced investors know to watch for warning signs that can turn a "great opportunity" into an expensive lesson.
Here are 10 red flags that should make you pause—or walk away.
1. Unrealistic pro forma rent
The flag: Seller's projected rent is 20%+ above current leases.
Why it matters: "Market rent" is meaningless if tenants won't pay it. Verify actual lease rates and compare to recent comps.
What to do: Use actual in-place rents for your analysis. If the upside is real, you'll capture it after you stabilize.
2. Suspiciously low expenses
The flag: Operating expenses below 35% of gross rent.
Why it matters: Someone's hiding costs. Property taxes, insurance, maintenance, and management add up.
What to do: Build your own expense model. Don't trust seller numbers—verify everything.
3. Deferred maintenance everywhere
The flag: HVAC is 20 years old. Roof is patched. Plumbing is original.
Why it matters: These are expensive repairs waiting to happen. A $15,000 HVAC replacement isn't a surprise—it's inevitable.
What to do: Get inspection estimates. Add deferred maintenance to your purchase price analysis.
4. High tenant turnover
The flag: Units turn over every 6-12 months.
Why it matters: Turnover is expensive—vacancy, make-ready costs, and leasing fees add up fast.
What to do: Ask why tenants leave. Is it the property, the area, or the management? Sometimes you can fix it; sometimes you can't.
5. Seller won't provide documents
The flag: No rent roll. No expense history. "Just make an offer."
Why it matters: If they won't show you the numbers, the numbers are probably bad.
What to do: Walk away, or make your offer contingent on full documentation.
6. Declining neighborhood indicators
The flag: Rising vacancy rates. Businesses closing. Population declining.
Why it matters: You can't fix a neighborhood. Macro trends will overpower your property performance.
What to do: Research the area. Look at job growth, population trends, and rental demand before committing.
7. Environmental concerns
The flag: Former gas station nearby. Property built before 1978. Flood zone location.
Why it matters: Lead paint, asbestos, mold, and environmental contamination create liability and remediation costs.
What to do: Order appropriate inspections. Check flood maps. Factor remediation into your numbers.
8. Title issues
The flag: Liens. Easements. Boundary disputes. Unclear ownership chain.
Why it matters: Title problems can delay closing, create legal liability, or make the property unsellable.
What to do: Order title search early. Require title insurance. Resolve issues before closing.
9. Non-conforming or illegal units
The flag: "Bonus" basement unit. Unpermitted addition. Zoning doesn't allow current use.
Why it matters: You can't legally rent non-conforming units. Insurance may not cover them. Fines and forced removal are possible.
What to do: Verify permits. Check zoning. If it's non-conforming, price it without the phantom income.
10. Numbers only work with aggressive assumptions
The flag: Deal only cash flows if you assume 100% occupancy, below-market expenses, and above-market rent growth.
Why it matters: Hope is not a strategy. Deals should work with conservative assumptions.
What to do: Stress test your numbers. If the deal breaks with realistic vacancy or expense assumptions, pass.
The bottom line
Every property has some risk. The goal isn't to find a perfect deal—it's to identify the risks and price them appropriately.
When you see red flags:
- Quantify the risk (what will it cost to fix?)
- Adjust your offer (price in the problem)
- Or walk away (there's always another deal)
Use Property Underwriting to systematically evaluate deals and catch red flags before they become expensive mistakes.