If you have lived on a well and septic system in Potomac for thirty years, there is a reasonable assumption sitting in the back of your mind: surely Maryland makes someone check that system before you can sell the house. It seems like the kind of thing a state government would require, the same way lenders require a termite inspection or a well flow test.
It doesn't. Not in Montgomery County. Not yet, anyway, and a bill that would have changed that statewide just died in Annapolis this spring after passing the House and then stalling in the Senate.
For families in Potomac's well-and-septic pockets, Glen Hills, the estate parcels along River Road, the custom homes off Falls Road, this is not a trivia question. It is the difference between a legally mandated checkpoint and a private negotiation that depends entirely on what gets written into the contract.
What Maryland Actually Requires, County by County
Maryland does not have a single statewide rule requiring a septic inspection when a home changes hands. Instead, a handful of counties layered their own local requirements on top of state law over the years. In Anne Arundel, Baltimore, Carroll, Frederick, Harford, and Queen Anne's Counties, a certified inspector has to examine the septic system before the property can be sold, and the results go to the local health department before closing can proceed.
Montgomery County is not on that list.
| Requires septic inspection at sale | Does not require it |
|---|---|
| Anne Arundel | Montgomery |
| Baltimore | |
| Carroll | |
| Frederick | |
| Harford | |
| Queen Anne's |
That gap matters more in Potomac than almost anywhere else in the county. Much of Potomac runs on WSSC public water and sewer, but pockets like Glen Hills and a meaningful share of the larger estate parcels toward Great Falls and the C&O Canal still rely on private wells and septic systems, the kind of large, wooded lots where public mains never got extended. A Potomac seller in one of those homes can list, negotiate, and close without a single county official ever laying eyes on the septic tank, unless the buyer's contract or lender specifically asks for it.
What Fills the Gap Instead
Montgomery County doesn't skip the topic entirely. It just handles it through disclosure rather than inspection.
Maryland's Residential Property Disclosure and Disclaimer Statement, the form every seller completes under the Real Property Article, asks directly whether the septic system is functioning properly and when it was last pumped. A seller who chooses full disclosure has to answer honestly. A seller who chooses the "as is" disclaimer option is largely exempt from that section, but state law still requires disclosure of latent defects the seller has actual knowledge of, meaning problems a buyer couldn't reasonably spot on a walkthrough.
Separately, Montgomery County's own disclosure practice for water and sewer service works through the Greater Capital Area Association of Realtors form, where sellers indicate whether the home is on public service or an on-site well and septic system, and where the county's Department of Environmental Protection can confirm which of its water and sewer service categories applies to a given parcel. Most owners, according to the county's own guidance, have no idea which category their property falls under until someone asks.
None of this is an inspection. It's a paper trail built on what the seller says they know, not on what a licensed professional finds when the tank comes open.
The Bill That Almost Changed the Default
This spring, Annapolis came close to closing that gap statewide. House Bill 146 and its Senate companion, Senate Bill 165, would have required septic systems to be inspected and pumped out before most residential sales and before new tenants move into a rental with a septic system, performed by an inspector licensed under the state's newer Board of On-Site Wastewater Professionals framework. An inspection done to satisfy the requirement would have stayed valid for three years in most cases, five years for a property's first transfer after construction.
The House passed its version 93 to 36 in February. Then the Senate's environmental committee amended the bill to strip out the inspection and pumping requirements entirely, and the two chambers couldn't agree on how to reconcile that before the session ended. The Maryland General Assembly adjourned sine die in April 2026, and the bill died with it.
For a Potomac seller today, the practical effect is that the status quo holds. No mandate. No statewide clock resetting the requirement every three to five years. Just the same patchwork that has Montgomery on one side of the line and Frederick and Carroll on the other.
Advocacy groups pushing the bill, including river conservation organizations tracking the outcome, argued the state's septic systems represent a genuinely large source of nitrogen pollution statewide and that inspection at the point of sale was a modest, well-timed way to catch failing systems before they became someone else's problem. Opposition centered on cost and timing concerns for the building industry. Both sides expect the fight to return in a future session, which means the rule that applies to a Potomac sale today is not guaranteed to be the rule that applies to the next one.
What a Careful Seller Does Anyway
None of this means a Potomac seller on well and septic should skip an inspection just because nobody is making them get one. If anything, the absence of a mandate is exactly why a voluntary inspection carries more weight.
A few things worth knowing before that conversation:
A typical septic inspection for a real estate transaction runs somewhere in the neighborhood of $400 to $700, depending on system complexity and how accessible the tank and distribution box are. Montgomery County's own code requires septic tanks to sit at least 100 feet from any well, at least 15 feet from any building, and at least 10 feet from a pool, and state regulations set separation distances between a septic drainfield and a well at 100 feet in an unconfined aquifer or 50 feet in a confined one. On an older Potomac lot, especially one where a pool or an addition came along after the original septic layout was approved, those distances aren't always where a homeowner assumes they are.
There's also the "actual knowledge" trap built into Maryland's disclosure law. Choosing the "as is" disclaimer doesn't erase a seller's obligation to disclose a problem they already know about. A homeowner who has lived with a slow drain or a soggy patch over the drainfield for years, and says nothing, is in a very different legal position than one who genuinely didn't know because no inspection was ever performed. An inspection converts what a family might vaguely suspect into a documented fact, which protects the seller as much as it informs the buyer.
For adult children coordinating a parent's move out of a longtime Potomac home, this is often the first concrete decision in a transition that otherwise feels abstract. It's a smaller, more answerable question than most of the ones a family is juggling at that stage, and it's one where a straight answer from a licensed inspector removes a genuine unknown from the sale.
A Few Questions Worth Asking First
Does a buyer's lender require a septic inspection even if the county doesn't? Often, yes. Many mortgage programs, particularly FHA, VA, and USDA loans, call for their own potability and system testing regardless of local mandates, so the absence of a county requirement doesn't necessarily mean a lender-financed buyer skips the topic.
If an inspection finds a problem, does the seller have to fix it? There's no legal requirement to repair a septic system that fails a voluntary inspection, since the inspection itself isn't mandated. In practice, most buyers will negotiate repairs, a price adjustment, or walk away, so the outcome depends on what the contract says rather than what the county requires.
Could Montgomery County or the state add a requirement later? It's possible. This year's bill came close enough that a version of it will likely return in a future legislative session, and several other Maryland counties already require what Montgomery doesn't.
A move out of a longtime Potomac home involves enough genuine unknowns already, family timing, what to keep, where everyone lands next. The septic question doesn't have to be one of them. If you're weighing what a sale in Glen Hills, along River Road, or anywhere else in Potomac's well-and-septic areas actually requires versus what's simply wise to do anyway, Next Step Living can walk through the specifics with you, at whatever pace makes sense for your family. Contact Us.
