Due Diligence Checklist: What to Inspect Before Buying a Wholesale Property

Why Due Diligence Is Non-Negotiable

Wholesale properties are sold as-is. There is no seller disclosure, no home warranty, and no obligation for the seller to fix anything. That means the burden of uncovering problems falls entirely on you, the buyer. In Baltimore County, where the average home age exceeds 50 years, skipping due diligence is the fastest way to turn a good deal into a money pit.

The due diligence window on most wholesale contracts is 7 to 14 days. Use every hour of it. The cost of inspections and research upfront -- typically $500 to $1,500 -- is a fraction of what you will spend fixing problems you did not anticipate. Here is your complete checklist.

Exterior Inspection

Start outside and work your way in. Check the roof: look for missing shingles, sagging ridgelines, damaged flashing, and gutter condition. A roof replacement in Baltimore County runs $6,000 to $12,000, so knowing its remaining life is critical. If you cannot access the roof, use a drone or binoculars to inspect from the ground.

Examine the foundation. Walk the perimeter and look for cracks wider than 1/4 inch, bowing walls, or evidence of previous patching. Baltimore's clay soil and freeze-thaw cycles are hard on foundations. Foundation repair can cost $5,000 to $20,000 depending on severity.

Check the siding, windows, and doors for rot, damage, or drafts. Look at the grading around the property: water should flow away from the foundation, not toward it. Check the condition of any retaining walls, fences, driveways, and walkways. These items may not be deal-breakers, but they add to your rehab budget.

Interior Systems: The Big Four

Inside, focus on the four major systems that determine your rehab budget. First, electrical: check the panel for its amperage (100-amp minimum for modern use), breaker type (replace Federal Pacific or Zinsco panels immediately), and wiring type. Knob-and-tube wiring, common in Baltimore homes built before 1950, requires rewiring at $8,000 to $15,000.

Second, plumbing: check pipe material. Galvanized steel pipes (common in 1950s to 1970s homes) are reaching end-of-life and should be replaced with PEX or copper. Look under sinks, in the basement, and at water heater connections. Run faucets to check water pressure and drainage speed. A full replumb costs $4,000 to $8,000.

Third, HVAC: check the age and condition of the furnace, air conditioning unit, and ductwork. Systems older than 15 to 20 years should be budgeted for replacement. A new HVAC system in Baltimore County runs $5,000 to $9,000 installed.

Fourth, the roof (from inside): go into the attic and look for daylight penetration, water stains, mold, inadequate insulation, and proper ventilation. The attic tells you more about roof condition than the exterior does.

Baltimore-Specific Hazards

Baltimore County has several area-specific hazards that every investor must check. Lead paint is the most significant. Any property built before 1978 likely contains lead paint, and Maryland law requires landlords to obtain a lead-safe or lead-free certificate before renting. Test for lead during due diligence so you can budget for abatement ($3,000 to $8,000) or encapsulation.

Asbestos is common in floor tiles, pipe insulation, and siding in homes built from the 1940s through the 1970s. Asbestos removal is regulated and expensive ($2,000 to $10,000 depending on scope). If you plan to disturb asbestos-containing materials during rehab, you must use licensed abatement contractors.

Termite damage is prevalent in Baltimore County's wood-frame and rowhome construction. Get a termite inspection ($75 to $150) and look for mud tubes on foundation walls, hollow-sounding wood, and damaged floor joists. Treatment costs $500 to $2,000, but structural repair from long-term damage can run $5,000 to $15,000.

Title and Legal Due Diligence

Beyond physical inspection, verify the property's legal status. Order a title search to check for liens, judgments, unpaid taxes, and ownership disputes. In Baltimore County, common title issues include unpaid water bills (which become liens), IRS and state tax liens, mechanics liens from previous contractors, and contested estates.

Check the property's zoning. Most Baltimore County residential properties are zoned DR (Dwelling Residential), but some older properties have non-conforming uses or split zoning that can affect your plans. If you intend to convert a single-family to a multi-unit, verify that zoning allows it.

Verify open permits. If previous owners pulled permits for work that was never inspected and closed, you inherit that liability. Baltimore County's permit portal (available online) lets you search by address to see permit history. Open permits must be resolved before you can pull new permits or sell the property.

Financial Due Diligence

Run your own comparable sales analysis. Do not rely solely on the wholesaler's ARV estimate. Pull recent sales (within 90 days) of similar properties within a half-mile radius. Adjust for condition, size, and location. If your ARV does not support the purchase price plus rehab with adequate margin, walk away.

Get contractor bids during the due diligence period, not after closing. Walk the property with your contractor and get a written scope of work with line-item pricing. Compare bids from at least two contractors. Use these real numbers -- not estimates -- in your pro forma.

Calculate your total carry costs: monthly holding costs multiplied by your expected project timeline (4 to 6 months for a flip, 2 to 3 months for a rental rehab). Add these to your acquisition and rehab costs to determine your true all-in investment. Only proceed if the numbers work with conservative assumptions.