Buying a House with Unpermitted Work in Montgomery County, MD

You found the house. A 1960s colonial in Bethesda with a finished basement, a big deck off the kitchen, and a bump-out addition that makes the main level finally work. Then your home inspector asks the question that stops everything: “Was this work permitted?”

It’s one of the most common surprises in Montgomery County transactions, and buyers ask about it constantly on Reddit, Bogleheads, and local forums. The housing stock in Bethesda, Chevy Chase, and Potomac skews heavily toward homes built between the 1950s and 1980s — which means nearly all of them have been renovated at least once, and some of that work was done without a permit. Whoever owns the home when the county finds out is the one who pays to fix it. After closing, that’s you.

Here’s how to find unpermitted work before you’re stuck with it, what it actually costs, and how to negotiate when you find it.

How to Find Unpermitted Work Before You Close

Montgomery County requires permits for more than most buyers expect. Additions, structural changes, finished basements, and decks — at any height — all require a building permit from the county’s Department of Permitting Services (DPS). So do most electrical, plumbing, and HVAC changes. A prior owner who “finished the basement themselves over a few weekends” almost certainly needed a permit to do it.

The good news: permit history is public, free, and takes about ten minutes to check. Three steps I walk buyers through during the inspection window:

• Search DPS eServices. Montgomery County’s online permit search at permittingservices.montgomerycountymd.gov lets you look up every permit on file for an address — no account required. Pull the list and match it against the renovations you can see. A finished basement with zero basement permits on file is your red flag.
• Compare the listing against the SDAT record. Maryland’s State Department of Assessments and Taxation records the official square footage and improvements for every property. If the listing advertises 4,200 finished square feet and SDAT shows 3,100, space was added or finished without the county catching up — a classic sign of unpermitted work.
• Ask your inspector to flag amateur work. Inspectors can’t verify permits, but they can spot the fingerprints of unpermitted construction: undersized framing, wiring without junction boxes, basement bedrooms missing egress windows, decks attached without proper flashing or footings.

One more wrinkle that’s specific to this county: if the home sits in one of Montgomery County’s historic districts — Carderock Springs in Bethesda is one example — exterior work also requires a Historic Area Work Permit from the county’s Historic Preservation Commission, on top of the standard building permit. A replaced fence, new windows, or a rebuilt porch in a historic district carries its own paper trail, and its own enforcement risk when that trail is missing.

The seller’s paperwork matters too. Maryland sellers who complete the Residential Property Disclosure form must disclose known material defects, and known unpermitted work falls squarely in that category. But many Montgomery County sellers choose the disclaimer (“as-is”) option instead — what sellers must disclose in Maryland explains the difference — and that shifts the burden of discovery almost entirely onto you. Even an as-is seller must disclose latent defects they actually know about, but you shouldn’t count on it. Verify independently.

What Unpermitted Work Does to Your Loan, Insurance, and Resale

This is where buyers underestimate the problem. Unpermitted work isn’t just a code technicality — it touches every financial layer of the purchase.

Your appraisal and loan. Appraisers generally won’t credit unpermitted square footage toward the home’s value. On a $1.2M Bethesda home where 800 of the advertised square feet sit in an unpermitted basement or addition, the appraisal can come in materially below contract price — and if the appraiser or underwriter flags a safety issue, your loan can be delayed, conditioned on repairs, or denied outright. FHA and VA loans are the strictest here.

Your insurance. Homeowners insurance carriers can deny claims that trace back to unpermitted work. If the DIY electrical in that finished basement starts a fire, or a guest is injured on an unpermitted deck, the carrier has grounds to fight the claim. You’d be carrying that risk every year you own the home.

County enforcement. If DPS discovers unpermitted construction — through a complaint, a later permit application, or a routine inspection — the current owner is responsible for legalizing it. That means a retroactive permit, plan review, and inspections that can require opening finished walls and ceilings so the county can see the framing, wiring, and plumbing. Retroactive permitting in Montgomery County typically costs 3–5x more than permitting the same work up front, and that’s before any corrective construction.

What does that look like in dollars? It varies with scope, but the pattern is consistent: the permit fees are the small part, and the corrective work is the big one. Bringing an unpermitted basement build-out to code commonly runs into five figures once you add a code-compliant egress window — typically $3,000–$8,000 installed — plus electrical corrections and the drywall repairs that follow inspection access. That’s the number you want to know before you sign, not after.

Your future resale. Once you know about the unpermitted work, you’ll need to disclose it when you sell. The problem doesn’t age out — it transfers, with interest, to whoever holds it last.

Your Options When You Find Unpermitted Work

Finding unpermitted work doesn’t automatically kill the deal. In this market it’s common enough that there’s a standard playbook. You have four moves, roughly in order of preference:

1. Ask the seller to legalize it before closing. The seller applies for a retroactive permit through DPS and brings the work to code at their expense. This is the cleanest outcome, but it takes time — plan review, inspections, and any corrective work can run 30–90 days, which may not fit your settlement date.
2. Negotiate a price reduction or credit. Get a contractor’s estimate for legalizing the work, then negotiate that number. This works like any inspection negotiation — how to negotiate after a home inspection in Bethesda covers the mechanics — but anchor to real bids, not guesses. Keep in mind that lender rules cap how much of a seller credit you can apply toward closing costs, so a price reduction is sometimes the better structure.
3. Accept it knowingly. For minor items — a shed, a fence, a water heater swap — many buyers accept the risk and move on. That’s a legitimate choice as long as you’re pricing the risk, not ignoring it. Get the scope documented in writing.
4. Walk away. For major unpermitted structural work — additions, load-bearing changes, full basement build-outs with bedrooms and no egress — where the seller won’t legalize or negotiate, walking is often the right call. Your inspection contingency exists for exactly this.

One more thing, because it matters in this market: in competitive Bethesda and Chevy Chase bidding situations, buyers are tempted to waive the home inspection to win. On an older, renovated home, that means waiving your best tool for catching exactly this problem. The permit search costs nothing and requires no contingency — run it before you even write the offer.

The homes most affected in our market are the ones that make this county great: 1950s–1980s houses in Bethesda, Potomac, Chevy Chase, North Potomac, and North Bethesda that have been expanded and finished over decades of ownership. Most of that work is fine. Some of it isn’t. The only way to know which house you’re buying is to check.

If you’re looking at a home and something about the square footage or the renovation history doesn’t add up, I’m happy to help you pull the permit record and think through the negotiation. Reach out anytime.