Do You Need a Plumbing Permit in Montgomery County, Maryland?

If you’re planning a plumbing project in Montgomery County, Maryland, one of the first questions that comes up is: “Do I need a plumbing permit?” The answer depends on the type of work being done—but in most cases, yes, you do.

However, here’s an important detail that many homeowners don’t realize: Plumbing permits in Montgomery County are not issued by the county itself. Instead, they’re issued by the Washington Suburban Sanitary Commission (WSSC Water), which handles water and sewer services for both Montgomery and Prince George’s Counties.

 Who Needs a Plumbing Permit?

Most significant plumbing work—whether you’re replacing a water heater, installing new water lines, or converting a system from gas to electric—must be performed by a WSSC-licensed plumber and requires a WSSC permit and inspection.

Here’s a breakdown of common projects and whether they require a permit:

Plumbing Task   Permit Required?

New water or sewer service lines              ✅ Yes

Whole-house re-piping ✅ Yes

Installing a gas water heater or furnace  ✅ Yes (Gas Permit)

Backflow preventer installation or replacement ✅ Yes (WSSC approval)

Toilet or faucet replacement (like-for-like)            🚫 Usually No

Fixing a leak or unclogging a drain             🚫 Usually No

Replacing less than 10% of existing piping             ❓ Possibly Exempt

 Gas Work: Extra Rules Apply

Gas appliances—including water heaters, boilers, and furnaces—require special attention. If you’re replacing or installing a gas-fueled appliance, you are legally required to get a WSSC gas permit and have the work performed by a WSSC-licensed gas fitter. This isn’t optional. It’s a safety matter, and insurance companies may deny claims on unpermitted work if something goes wrong.

 What About Minor Repairs?

Not every little job needs a permit. According to WSSC’s code (section 106.2.1), certain repairs may be exempt—for example, if you’re fixing a leaky pipe or replacing a small section of piping (less than 10% of the total). Still, it’s a gray area, and your plumber should verify whether your specific project qualifies.

 Why It Matters

Even if you’re tempted to skip the paperwork, getting the proper permits protects you:

Safety: Inspections ensure the work meets code and won’t risk your health or property.

Home resale: When you sell your home, unpermitted work can delay the process or lower your home’s value.

Insurance coverage: If something fails (like a water heater) and you didn’t pull a permit, your insurer may deny your claim.

 What You Should Do Next

Ask your plumber if the job requires a WSSC permit. If they’re licensed, they’ll handle it for you.

If you’re doing gas work or anything beyond a minor repair, assume a permit is required.

Double-check with WSSC Water if you’re unsure. You can call Permit Services at 301-206-4003 or visit their ePermitting portal online.

In Summary:

You may not need a Montgomery County permit—but if you’re doing plumbing work in Montgomery County, Maryland, WSSC Water rules apply. For most substantial projects, including gas appliance replacements, water service upgrades, or backflow prevention installations, you’ll need a permit and inspection from WSSC.

When in doubt, always check. A licensed plumber will keep your project safe, legal, and stress-free.