Fixed pricing from $3,895 installed. We serve 1 ZIP code across Darnestown — 20878 — with same-week install availability and every rebate filed for you. 6,800 residents.
Darnestown has approximately 6,800 residents and a diverse housing stock — a combination that means thousands of aging 40–50 gallon gas storage tanks are hitting end-of-life at any given moment. The vast majority of those homeowners are now choosing tankless replacement rather than like-for-like tank swaps, and for good reason: endless hot water, 20+ year lifespan, and roughly $95–$200/year in energy savings per Washington Gas data.
Darnestown has a mix of municipal and well-water homes — a distinction that matters enormously for tankless longevity. We're one of the few installers in the DMV who routinely serve both configurations and publish upfront pricing for the well-water pre-filter add-on.
Darnestown shares WSSC water service with North Potomac. A portion of Darnestown homes remain on well water, which requires our optional pre-filter add-on to protect the tankless heat exchanger from sediment.
Darnestown is under Montgomery County permit jurisdiction. Rural/large-lot properties may require additional site survey during permit review.
Darnestown is underserved by DMV plumbing companies — most consider it too far out for efficient routing. We don't. Our same-week install commitment applies here identically to Rockville.
From your first consult to a hot shower is typically 8–12 business days — nearly all of which is Montgomery County permit processing time. Install day itself is a single 6–8 hour visit: we arrive around 8am, the old tank is removed by noon, and the new tankless unit is mounted, commissioned, and flushed before dinner.
We've completed installs throughout Darnestown, including:
Every Darnestown install falls into one of three published fixed-price tiers. See full pricing and stipulations, or use the instant estimator to see which tier fits your home.
45-minute in-home assessment. Locked-in fixed price at consult, no callbacks.
Book a consult →Every review below is from a real Darnestown homeowner who approved us to publish their install. See all reviews.
"Had three Darnestown plumbers give me totally different numbers for the same scope. DMV Tankless was the only one who published pricing online. The price I saw was the exact price I paid."
"Installed the Navien 240A2 with recirculation in our Darnestown home. Hot water at every tap in about 8 seconds. Team was in and out in one day — old tank gone, new unit mounted, everything working."
"Best part was they handled the Montgomery County permit and Washington Gas rebate paperwork. Rebate check arrived about 6 weeks later — a real $450 I would not have bothered to file on my own."
These are the actual questions we get during Darnestown consults. See the full FAQ for more.
Our three fixed tiers apply identically across all Darnestown ZIP codes (20878): Essential at $3,895, Signature with recirculation at $5,295, and Whole-Home Pro at $7,495. All prices are all-in including Montgomery County permit, standard venting, gas connection, condensate tie-in, old-tank haul-away, first-year flush, and rebate paperwork. Typical Darnestown homeowners qualify for $1,150–$1,400 in stacked rebates.
Install day itself is 6–8 hours. From your first consult to install is typically 8–12 business days in Darnestown — the majority of that time is Montgomery County permit processing. Emergency installs (same-week) are available for a flat $395 rush fee.
Yes. Every Darnestown install includes Montgomery County permit filing and inspection scheduling as part of the fixed price. Skipping the permit voids homeowners insurance coverage for water damage claims and creates issues at resale. We hand you the signed-off inspection card before we consider the job complete.
Darnestown homeowners stack four rebates: Washington Gas rebate up to $450, Maryland manufacturer rebate of $100, federal tax credit of 30% (up to $600), and Montgomery County property tax credit up to $250 — totaling up to $1,400. We file every form on your behalf. See our full rebates page for details.
We install three brands in Darnestown: Navien, Rinnai, and Rheem. These are the only brands with reliable parts availability, strong warranty support, and proven 20+ year longevity in DMV water conditions. We decline to install off-brand tankless units regardless of price — we won't install what we can't stand behind for two decades.
Same fixed pricing. Same published stipulations. Same next-week install availability.
Licensed master plumber verifies sizing, locks your fixed price, answers every question. Zero commitment. Most Darnestown consults booked within 72 hours.