Philadelphia property due diligence checklist: what to check before you buy

Philadelphia has some of the most publicly accessible property data in the country. L&I records, OPA assessments, permit history, 311 complaints, flood zone maps, sheriff sale listings. Nearly all of it is free, online, and searchable by address. The problem is that it's spread across eight different city and federal databases, most of them designed for city staff, not buyers.

This checklist covers every layer of research that matters before you commit to a Philadelphia property, whether you're a first-time homebuyer, a buy-and-hold investor, a house flipper, or an attorney doing title review. Work through it in order. Some layers take two minutes; a few take longer if you find something worth digging into.

Layer 1: L&I violations

Philadelphia's Department of Licenses and Inspections (L&I) maintains a public database of every code violation ever issued against a property. Open violations, ones that haven't been resolved, transfer with the property. You can inherit them at closing.

The database is at li.phila.gov (search by address). What you're looking for:

• Open vs. closed: Open violations are the ones that matter. Closed violations tell the story of how the property has been maintained.
• Housing violations: Habitability issues, including lacking heat, water, pest infestation, roof failure. These can block financing if the property needs to be habitable for an FHA/conventional loan.
• Zoning violations: Unpermitted additions, illegal conversions, non-conforming use. May require a variance, demolition, or re-permitting to resolve.
• Building code cases: Structural, electrical, plumbing issues. Check whether permits were later pulled to legalize the work.
• Fire code cases: Smoke detectors, sprinklers, egress, especially relevant in multi-unit properties.

For a full breakdown of violation categories and severity, see our guide: Philadelphia L&I violation types explained.

Layer 2: Permit history

Permit records tell you what work was done to the property and whether it was done legally. In Philadelphia, this matters more than in most cities. Unpermitted work is common, and it creates liability for buyers who inherit it.

Also at li.phila.gov. What to look for:

• Permits with no final inspection: A permit was pulled but the city never came to sign off. The work may be incomplete, non-compliant, or was abandoned.
• Work without permits: Cross-reference what you observe in person with what's in the permit record. A new addition with no permit is a red flag.
• Electrical / plumbing permits: These require licensed contractors and inspections. Absence is a warning sign for DIY work.
• Recent demo permits: Someone tore something down. Why? Is there a related violation?
• Zoning approvals: Any use change requires a ZBA approval or variance. Check the permit for the approval number.

Full explainer: Philly building permits lookup: what the records actually tell you.

Layer 3: 311 service request history

Philadelphia's 311 system logs every service request filed about a property, including neighbor complaints about trash, reported break-ins, utility complaints, and more. It's not just about violations; it's about the property's history as a neighbor problem.

Search at phila.gov/311 or via the city's open data portal (phl.data.phila.gov). Look for:

• Repeated complaints from the same neighbors (chronic issues, not one-off)
• Rodent or pest complaints (can indicate ongoing sanitation issues)
• Abandoned vehicle or illegal dumping complaints associated with the address
• Water/flooding complaints (may indicate basement or drainage issues)
• Graffiti or vandalism complaints (neighborhood context)

Layer 4: OPA (Office of Property Assessment) records

The OPA database contains the official city assessment for every property: assessed value, the calculation used to set it, and the owner of record. It's also where you can confirm whether a property has an active tax abatement.

Search at property.phila.gov. Key fields:

• Assessed value vs. purchase price: If you're paying significantly above assessed value, know the reassessment risk. If assessed value is far above market, there may be a pending appeal.
• Active abatement: Many renovated Philly properties have a 10-year tax abatement. Check when it expires. The tax bill after expiration can be dramatically higher and should factor into your underwriting.
• Owner of record: Confirm the seller is actually the owner of record. If there's a mismatch, investigate before signing anything.
• Land use designation: Matches the zoning category (see Layer 6). Discrepancies between actual use and designation are red flags.

Layer 5: Tax delinquency and liens

Property tax liens in Pennsylvania are super-priority, meaning they take precedence over almost all other liens, including mortgages. A lien that wasn't disclosed or wasn't caught in title search can survive a sale and follow you.

Check the city tax payment portal and the Bureau of Revision of Taxes (BRT) database. Look for:

• Outstanding tax balance: Even a small balance owed signals risk. Is the seller solvent?
• Tax sale status: Properties can be listed for sheriff sale without any visible sign on the property. A delinquency of 1+ year is sheriff sale eligible.
• Other municipal liens: Water/sewer arrears, demolition cost recovery, and code compliance costs can all attach to a property as liens.
• BRT vs. OPA discrepancy: BRT handles tax appeals; if there's a pending appeal, the assessed value (and tax bill) may change.

For more on this layer: Philadelphia tax delinquency: what it means for buyers and investors and Philadelphia sheriff sales explained.

Layer 6: Zoning and land use

Zoning determines what you can do with the property, now and in the future. In Philadelphia, ADU potential, short-term rental legality, and commercial-to-residential conversions all hinge on the zoning designation.

Look up the zoning designation at atlas.phila.gov. Match it to what you intend to use the property for.

• RSA-5: Typical Philly rowhouse zoning. Single-family residential. A second unit is technically a violation without a variance.
• RM-1/RM-2/RM-3: Multi-family residential. You can have multiple units legally.
• CMX-1/CMX-2: Commercial mixed-use. Ground-floor commercial allowed or required. Good for live/work; harder to finance purely residential.
• Non-conforming use: If the current use doesn't match the zoning but predates current code, it may be grandfathered, but only if it remains continuous. A vacancy period can extinguish non-conforming use rights.

Full guide: Philadelphia zoning codes explained: a guide for buyers and investors.

Layer 7: Flood zone status

Philadelphia has significant flood risk, along the Schuylkill, the Delaware, Tacony Creek, and smaller waterways throughout the city. If a property is in a Special Flood Hazard Area (SFHA), federally-backed loans require flood insurance, which can add $1,000–$3,000+ per year in carrying costs.

Check FEMA's Flood Map Service Center at msc.fema.gov. Enter the address and identify the flood zone designation:

• Zone X: Minimal risk. No flood insurance required.
• Zone AE / Zone A: High risk. Flood insurance required for federally-backed loans. Re-underwrite with flood insurance cost factored in.
• Zone VE: Coastal high-hazard area. Not common in Philly but exists near the Delaware.
• Zone X500: Moderate risk (0.2% annual chance). Insurance not required but worth considering.

Full guide: Philadelphia flood zone lookup: what every buyer and investor needs to know.

Layer 8: Title search and encumbrances

A title search is the only way to catch liens, encumbrances, and ownership issues that the public databases don't surface. In Pennsylvania, buyers typically pay for title insurance. Use an attorney or title company, not just an online service.

• Mechanic's liens: Contractors can file liens for unpaid work. These attach to the property, not the owner.
• Judgment liens: If the owner has an unsatisfied court judgment, it may attach to real property they own in Pennsylvania.
• Open mortgages: Confirm the stated mortgage balances match what's in the recorder of deeds. Sellers don't always disclose second mortgages.
• Estate issues: If the property transferred via estate, confirm proper probate proceedings and that all heirs signed off.
• Chain of title defects: Missing assignments, improper notarizations, old mortgages never formally discharged.

Layer 9: Physical inspection

No amount of record research substitutes for a licensed inspector walking the property. Philadelphia rowhouses have specific failure modes worth knowing about before the inspection so you can ask the right questions:

• Party walls: Shared walls between rowhouses can have issues that don't appear on your side. Ask about water infiltration, structural cracks, and fire separation.
• Flat roofs: Common in Philly rowhouses; they typically need replacement every 15–20 years. Get the age and ask for the last service record.
• Knob-and-tube wiring: Older rowhouses may still have original electrical. Uninsurable by many carriers without full rewire.
• Lead paint: Required disclosure for homes built before 1978. Philadelphia has one of the highest childhood lead poisoning rates in the country. Take this seriously.
• Basement water infiltration: Cross-reference with 311 water complaints. Sump pump? French drain? Active cracks in foundation walls?
• HVAC age and condition: Philadelphia winters are cold; a failing system in year one is an expensive surprise.

Putting it all together

Philadelphia's public records are unusually rich, more accessible than most American cities. Buyers and investors who use them have a genuine edge: they can price risk accurately, negotiate from strength, and avoid surprises that kill deals after closing.

Work the checklist in layers. Layers 1–5 are fast (30–90 minutes total) and public. Layer 6 (zoning) takes another 10 minutes but is critical for investors. Layer 7 (flood) is a quick lookup that has outsized financial implications. Layer 8 (title) requires a professional and takes longer but is non-optional. Layer 9 (physical) is scheduled separately and should happen before your inspection contingency expires.

If you find something, name it clearly in your inspection response or addendum. "Property has an open L&I violation at 123 Elm St for deteriorated exterior masonry; seller to provide written resolution or price reduction of $X before closing." Specificity is leverage.