What Is Due Diligence in Commercial Real Estate? (Simple Checklist)

Signing the purchase agreement feels like the finish line.

It isn’t. It’s the start of the most important few weeks of the whole deal.

Between signing and closing, there’s a window where you’re allowed to look under every rock. Roof, title, tenants, zoning, environmental history. If you find something, you can still renegotiate or walk away.

After that window closes, whatever you missed is yours.

That window is due diligence. Here’s how to use it.

The Short Answer

Due diligence is the period after you sign a purchase agreement when you investigate the property before your deposit becomes non-refundable.

You check five things:

• The building: its physical condition
• The land: title, boundaries, and survey
• The environment: contamination history
• The rules: zoning and permits
• The money: leases, income, and expenses, if there are tenants

Each one can uncover a problem big enough to change the price. A few can kill the deal outright.

What’s on the Due Diligence Checklist?

The building

• Property condition inspection: roof, HVAC, structure, plumbing, electrical
• Parking surfaces and drainage
• Accessibility requirements
• Remaining useful life of major systems

Title and survey

• Title commitment: who owns it, and what liens, easements, or restrictions come with it
• Land survey: boundaries, encroachments, and access

Commercial surveys follow a national standard. ALTA and NSPS finalized updated requirements for commercial land title surveys that took effect February 23, 2026, according to McGuireWoods. If you’re ordering one now, ask for the 2026 standard. 

Environmental

• A Phase I environmental site assessment (more on that in the next article)
• Any past uses like gas stations, dry cleaners, or manufacturing on or near the site

Zoning and permits

• Is your intended use legally allowed?
• Open code violations or unpermitted work
• Certificate of occupancy

Income and leases (if the building has tenants)

• Every lease, compared against the rent roll
• Tenant estoppel certificates
• Bank statements showing rent actually received
• Two to three years of operating statements, property tax bills, and insurance history

That’s the list. Now here’s how to fit it into the time you get.

How Long Does Due Diligence Take?

As long as your purchase agreement says. The window is negotiated, and once it’s set, the clock doesn’t care how slow your surveyor is.

So schedule it like a project. Here’s an illustrative 45-day window for our HVAC contractor’s $1.2M flex building:

• Days 1 to 5: Order the inspection, Phase I, survey, and title commitment. Request every document from the seller.
• Days 5 to 20: Inspection on site. Review title. Confirm zoning with the city.
• Days 20 to 35: Phase I, survey, and appraisal results come in. Get repair quotes for anything the inspection flagged.
• Days 35 to 42: Decide. Renegotiate, request credits, or prepare to proceed.
• Days 42 to 45: Send any written notice the contract requires before the deadline.

The most common mistake isn’t missing a problem. It’s ordering reports in week three and running out of time to act on them.

What Does Due Diligence Cost?

Real money. But far less than the problems it catches.

Math time (illustrative, costs vary widely by market and property):

• Property condition inspection: $4,000
• Phase I environmental assessment: $3,000
• ALTA survey: $5,000
• Appraisal (usually required by your lender): $4,000
• Attorney review of title, leases, and contract: $8,000
• Total: about $24,000

That’s 2% of the $1.2M price.

Now compare it to one finding. Back in our earlier example, the inspection uncovered a roof needing $90,000 of work within two years. Spotting it before closing let the buyer price it into the offer.

$24,000 to find a $90,000 problem is a good trade. Skipping due diligence to save $24,000 is how buyers end up paying for the roof, the environmental cleanup, and the lawyer.

What Happens If You Find a Problem?

You have four options, as long as you’re still inside the window:

• Renegotiate the price. Use repair quotes to back up the number.
• Ask for a credit. The seller pays toward the fix at closing, and the price stays the same on paper.
• Ask for an extension. If a report is late or a problem needs more investigation, request more time in writing before the deadline.
• Walk away. If the contract allows it, you can terminate and usually get your deposit back.

What you can’t do is wait. Most contracts require written notice by a specific date. Miss it, and your deposit often becomes non-refundable, problem or not.

Read your contract’s due diligence clause before you sign it, not after you find the problem.

Recap

• Due diligence is the window to investigate a property before your deposit goes hard.
• Check five areas: building, title and survey, environmental, zoning, and income.
• Commercial surveys follow the 2026 ALTA/NSPS standards, effective February 23, 2026.
• Schedule reports in the first week. Leave time at the end to decide.
• Due diligence on a $1.2M building might run about $24,000 (illustrative). One finding can pay for it several times over.
• If you find a problem, renegotiate, ask for a credit, extend, or walk, in writing and on time.

Final Word

Due diligence isn’t about proving the building is perfect.

No building is. It’s about knowing exactly what’s wrong before you own it, while you can still do something about it.

Order early. Read everything. Put your decisions in writing before the clock runs out. That’s the whole job.

Browse commercial listings at hutfin.com.