Plenty of Potomac and North Potomac homes sit on private well water and septic systems instead of public utilities, and that's not a dealbreaker — but it changes your inspection list and your budget. Plan on roughly $400–$650 to inspect both systems, know that an FHA loan requires a passing water test and specific well-to-septic distances, and understand that a failed drainfield or septic replacement can run $10,000–$20,000+. The fix is simple: test thoroughly during your contingency window so you buy with eyes open.
Quick Answer
Plenty of Potomac and North Potomac homes sit on private well water and septic systems instead of public utilities, and that's not a dealbreaker — but it changes your inspection list and your budget. Plan on roughly $400–$650 to inspect both systems, know that an FHA loan requires a passing water test and specific well-to-septic distances, and understand that a failed drainfield or septic replacement can run $10,000–$20,000+. The fix is simple: test thoroughly during your contingency window so you buy with eyes open.
Some of the most desirable properties in Potomac — the larger lots, the estate-style homes, the privacy you can't get downtown — aren't connected to public water and sewer. They run on a private well and an on-site septic system. If you've spent your search looking at homes in Bethesda or North Bethesda, where public utilities are the norm, this can feel like uncharted territory.
It isn't. Thousands of Montgomery County households live comfortably on well and septic. But the systems are yours to maintain once you own them, and a failure can be expensive. So before you write an offer on a Potomac home with these systems, here's exactly what to check and what to budget.
What changes when there's no public water or sewer
A well draws your drinking water from groundwater on the property. A septic system treats and disposes of wastewater on-site, usually through a tank and an underground drainfield. There's no monthly water or sewer bill — but there's no utility company to call when something breaks, either. You are the utility.
That's why your due diligence list grows. On a public-utility home in Chevy Chase, your inspection focuses on the structure. On a well-and-septic home in Potomac, you're inspecting the structure and two systems that, if they fail, can cost as much as a kitchen renovation to replace.
The good news: these systems are testable. You don't have to guess.
The inspections you actually need
A standard home inspection does not fully cover the well or the septic. You'll want dedicated specialists, and most buyers schedule these during the inspection contingency period. Here's the typical breakdown in the Potomac area:
- Well inspection: $250–$450. Checks the pump, pressure tank, flow rate, and mechanical components.
- Water quality test: $100–$350. Lab screening for bacteria (coliform), nitrates, and often lead.
- Septic inspection: $300–$500 standard; a camera scope of the tank can push it toward $700–$900.
- Combined well + septic: Often $400–$650 when scheduled together — cheaper than booking separately.
This is the same instinct that makes radon testing during a Montgomery County purchase worth the small upfront cost. Spend the money. A failing drainfield or a contaminated well is exactly the kind of issue you want to discover before closing, not after.
How your loan type sets the rules
FHA loans are the strictest. They require both a well water test (valid 180 days) and a septic test. The well casing must be at least 50 feet from the septic tank and 100 feet from the drainfield (sometimes 75 feet if the local authority allows), with a sustained flow of 3–5 gallons per minute. Water must test clean: nitrates at or below 10 mg/L and coliform absent.
VA loans always require a water-quality test (valid 90 days) but only require a septic test if a problem is noted.
Conventional loans are the most flexible — inspections are typically required only if the appraiser flags a hazard. But you should still test anyway; leniency doesn't protect you from a $15,000 repair.
What it costs if something's wrong
- A new well pump or pressure tank: a few hundred to a couple thousand dollars.
- Drilling or replacing a well: $5,000–$10,000+.
- A septic drainfield repair or full replacement: $10,000–$20,000+, especially if a Best Available Technology (BAT) nitrogen-removal unit is required, which alone adds roughly $6,000–$15,000.
Maryland's Bay Restoration Fund can cover 50–100% of a BAT upgrade for qualifying owners, but it prioritizes failing systems in the Chesapeake Bay Critical Area — most of Montgomery County sits outside that zone, so budget as if the repair is yours.
The takeaway isn't fear — it's leverage. A failing system is a number you bring to the negotiating table: a price reduction, a seller-funded repair, or a credit at closing.
How Montgomery County fits in
In Montgomery County, the Department of Permitting Services (DPS), acting for the Maryland Department of the Environment, handles well and septic testing and permitting. If you ever plan to add on or build, the property needs satisfactory percolation and water-table testing — and the county only runs water-table tests during the seasonal high-water window, generally February through mid-April.
So is a well-and-septic home worth it?
For a lot of Potomac buyers, absolutely. You're often trading a monthly utility bill for more land, more privacy, and a competitive price. The key word is informed. Test both systems, match your inspection plan to your loan, and budget a repair reserve — the same discipline that keeps your overall buyer closing costs from surprising you. From there, the path to settlement looks like any other Maryland closing.
The bottom line
A well-and-septic home in Potomac isn't a risk to avoid — it's a property type to understand. Test both systems, match your inspections to your loan, and budget a reserve, and you'll buy with confidence. If you want help reading inspection results or pricing in the risk, I'm happy to walk you through the numbers.
About Pey Behin — Pey Behin is a residential real estate agent serving the Washington, DC metro area, with a focus on Bethesda, Montgomery County, and Northern Virginia. He works with buyers and sellers who want clear strategy, data-driven pricing, and direct guidance throughout the transaction process.