Nobody wakes up excited about permits.

I know this because I watch people’s faces when I bring it up. They’re all enthusiastic about adding that master suite or expanding the kitchen, and then I mention permits and suddenly they look like I just told them they need a root canal.

But here’s the reality. If you’re adding space to your Montgomery County home, you need permits. And honestly? You should want them, even though the process can be annoying.

I’ve been helping homeowners navigate the permitting process in Gaithersburg, Rockville, and all over Montgomery County for years. I’ve seen what happens when people skip it (spoiler: it’s expensive and terrible), and I’ve figured out how to make the process as painless as possible.

Let me walk you through what you’re actually dealing with.

Why Permits Exist (And Why You Actually Want Them)

Permits aren’t just the county trying to extract money from you, though I know it feels that way sometimes.

They make sure your addition is built safely and meets current building codes. They create a paper trail that proves the work was done legally, which matters huge when you sell. They ensure proper inspections happen at critical stages so problems get caught before they’re hidden behind drywall.

I’ve bought houses where the previous owner did unpermitted work. It’s a nightmare. You can’t get it insured properly. Banks won’t give you a mortgage without sorting it out first. And if there’s ever a problem, your homeowner’s insurance can deny your claim.

Had a client last year who bought a house in Silver Spring with an unpermitted addition. Discovered it during the home inspection. The sellers had to either get it permitted retroactively (expensive and complicated) or take $40,000 off the sale price. Guess which option they went with?

Don’t be those people.

What Needs a Permit

Pretty much any addition to your house needs a permit. Room additions, second story additions, garage conversions, enclosed porches that become living space—all of it requires permits.

If you’re doing structural work—removing walls, adding walls, touching the foundation—you need a permit. New electrical work beyond just swapping out a light fixture? Permit. New plumbing or relocating existing plumbing? Permit. HVAC work for the addition? Permit.

What doesn’t need permits? Painting, replacing flooring, installing new cabinets (as long as you’re not changing plumbing or electrical), basic repairs that maintain the existing condition.

When in doubt, assume you need one. I’ve never seen anyone get in trouble for getting a permit when they technically didn’t need it. I’ve seen plenty of people get in trouble for skipping permits they needed.

Where You Get Your Permits (Because It’s Confusing)

This is where it gets messy. Where you live in Montgomery County determines who issues your permits.

Most of Montgomery County is unincorporated—places like Potomac, Bethesda, Chevy Chase, Silver Spring, Olney, Darnestown, all those areas. You deal with Montgomery County Department of Permitting Services. They’re at 255 Rockville Pike, and you can call them at 240-777-6370 if you have questions.

But if you live within Rockville city limits, you get your permits from the City of Rockville. Different office, different process, different people.

Same deal with Gaithersburg. City of Gaithersburg handles permits for properties inside city limits.

And just to make it extra confusing, plumbing permits always go through WSSC (Washington Suburban Sanitary Commission) regardless of where you live. County, Rockville, Gaithersburg—doesn’t matter. Plumbing goes through WSSC.

I know this seems unnecessarily complicated. It is. But that’s how it works.

The Permits You’ll Actually Need

Most additions need at least two or three permits, sometimes more.

The building permit is your main one. It covers all the structural work, framing, foundation, general construction stuff. This one usually costs $250 to $1,500 depending on the size and value of your project. Takes 2-4 weeks to get approved, sometimes longer if your plans need corrections.

Electrical permit covers all your electrical work—new circuits, outlets, lighting, panel upgrades if needed. Runs $150 to $500 typically. You usually need a licensed electrician to pull this one. Takes about 1-2 weeks.

Plumbing permit through WSSC covers water supply lines, drain lines, fixtures, anything plumbing-related. Figure $100 to $400. Takes 1-3 weeks usually.

If you’re adding HVAC to the addition or extending your existing system, that’s another permit. Usually $150 to $400.

Some projects need additional permits too. Sediment control if you’re disturbing a lot of earth. Stormwater management for bigger additions. Right-of-way permits if you’re working near the street.

We handle all this, but I want you to know what you’re dealing with.

The Actual Process (Step By Step)

Before you even apply for permits, you need to do your homework.

Check your zoning. Make sure your addition doesn’t violate setback requirements (how close you can build to property lines), lot coverage limits (how much of your lot can be covered by buildings), or height restrictions. This stuff varies by neighborhood.

If you’ve got an HOA, deal with them first. Some HOAs take forever to review and approve plans. Start that process early.

Check for easements or deed restrictions that might affect what you can build where.

Then you need actual plans. Architectural drawings showing what you’re building, where it goes on your property, how it’s constructed. You need a site plan, foundation plan, floor plans, elevations, cross-sections, roof framing plan, all of it.

For simple additions, an experienced contractor can sometimes prepare the plans. More complex stuff needs a licensed architect.

You submit your application with all the plans and supporting documents. Three sets of plans usually. Site plan. Survey or plat. HOA approval if applicable. Energy compliance calculations. Your contractor’s MHIC license information.

Then you wait while the county or city reviews everything. Building code compliance people check it. Zoning reviews it. Fire marshal might review it depending on the project. Environmental health if you’ve got a septic system.

Takes 2-6 weeks typically, though I’ve seen it take longer for complicated projects or if the county’s backed up.

They either approve it, require corrections, or ask for more information. If it’s approved, great. If they want changes, you fix the plans and resubmit.

Once everything’s approved, you pay your fees and get your permits. Now construction can start.

But getting the permits is just the beginning. During construction, you need inspections.

Foundation inspection after excavation and before you pour concrete. Framing inspection after framing’s complete but before you cover it with drywall. Rough-in inspections for electrical, plumbing, and HVAC before those get covered up. Insulation inspection. Final inspection when everything’s done.

Never cover up work that needs inspection. If the inspector fails something, you fix it and call for re-inspection.

After you pass final inspection, you can get your Certificate of Occupancy. That’s the official document saying your addition is legal and safe to occupy. You need it before you can legally use the space.

Common Problems (And How to Avoid Them)

Setback violations are probably the most common issue I see. Your addition would extend too close to the property line.

Solutions: redesign to meet setbacks, apply for a variance (long process, no guarantee), or build up instead of out with a second story.

Lot coverage issues happen when your addition would cover more of your lot than zoning allows.

Fix it by making the addition smaller, removing other structures (like that old shed), or applying for a variance.

HOA delays can kill your timeline. Some HOAs meet once a month. If you miss the submission deadline, you’re waiting another month. Then they might want changes, and you’re waiting another month.

Start the HOA process early. Go to meetings if you can. Make sure your plans follow their guidelines before you submit.

Incomplete documentation is an easy one to avoid. Just make sure you’ve got everything on the checklist before you submit. Missing documents just delay everything.

Failed inspections happen. Sometimes it’s a legitimate problem that needs fixing. Sometimes the inspector’s just picky. Either way, fix it and schedule a re-inspection promptly.

What This Costs

Permits themselves aren’t that expensive compared to the overall project cost.

Building permit: $250-$1,500 usually Electrical: $150-$500 Plumbing: $100-$400 HVAC: $150-$400

Plan review fees are usually built into the building permit cost.

But there are other costs too. Architectural or design plans run $2,000 to $8,000 for most projects, more for complex additions. Land survey might be $400 to $1,500. Soil testing if needed, engineering if required.

Total permit-related costs usually run 2-4% of your total project budget.

How Long Everything Takes

From start to finish, plan on 10-22 weeks before construction even begins.

Design and planning: 4-8 weeks HOA approval (if applicable): 4-8 weeks, and you can do this while designing Permit submission to approval: 2-6 weeks Total pre-construction: anywhere from 2.5 months to 5.5 months

Then construction with inspections: Small addition under 200 square feet: 2-4 months Medium addition 200-500 square feet: 4-6 months Large addition over 500 square feet: 6-10 months Second story addition: 6-12 months

Yeah, it’s a long process. But good planning upfront prevents expensive mistakes during construction.

The MHIC License Thing

Every contractor in Maryland must be licensed through the Maryland Home Improvement Commission. Not some, not most—every single one.

You can verify a license online at mhic.maryland.gov. Takes two minutes. Do it before you hire anyone.

Licensed contractors can legally pull permits. They’re required to have insurance. They’re bonded. There’s a guaranty fund that can help if things go wrong. You have actual legal recourse if they mess up.

Unlicensed contractors can’t legally pull permits. If they get caught, you’re the one dealing with the consequences. And if something goes wrong, you’re basically on your own.

I’ve cleaned up enough unlicensed contractor disasters that I’m probably too intense about this. But seriously. Only hire MHIC-licensed contractors.

Special Cases

If you’re in a historic district—parts of Rockville, Takoma Park, some Silver Spring neighborhoods—you’ve got extra hoops.

You need Historic Preservation Commission approval before you can even apply for building permits. They’ll review your design to make sure it’s appropriate for the historic character. This adds 4-8 weeks to your timeline and might restrict what you can do.

Not impossible, just more complicated. Work with someone who’s done historic district projects before.

What You Can’t Do

Don’t start work before permits are issued. You’ll get a stop work order, possible fines, and you might have to tear out work you’ve already done.

Don’t skip required inspections. You won’t pass final inspection, can’t get your Certificate of Occupancy, and the space legally can’t be used.

Don’t make changes without approval. If you decide to move a wall or change something significant, you need to update your plans and get approval.

Don’t hire unlicensed contractors. I know I keep saying this, but it’s that important.

Why Use Us for Your Permitted Addition

We handle the whole permit process as part of our service.

We verify zoning compliance before you spend money on plans. We coordinate with architects and designers. We prepare complete permit packages. We submit applications and track their progress. We respond to correction requests. We schedule all the inspections during construction. We make sure everything passes on the first try (usually). We get your Certificate of Occupancy.

Our experience means faster approvals, fewer corrections, inspections that pass the first time, and no surprises.

We know Montgomery County’s system. We know Gaithersburg’s process. We know Rockville’s requirements. We know which inspectors are particular about what. We’ve got relationships with suppliers and subs who show up when they’re supposed to.

That stuff matters when you’re trying to get a project done on time and on budget.

Let’s Get Your Addition Permitted and Built

The permitting process seems intimidating, but it’s just a series of steps. Do them in order, do them properly, and you get through it.

We’ve walked hundreds of Montgomery County homeowners through this. We know it inside and out, and we make it as painless as possible so you can focus on the fun part—designing your addition and watching it take shape.

Call us at 240-449-5164. We’ll talk about what you want to add to your house and handle all the permit stuff so you don’t have to.