Montgomery County's tankless-only specialist ★ 4.9 · 200+ installs

Endless hot water.
Fixed price.
One day.

We're the only plumber in Rockville, Potomac, and Gaithersburg who does one thing — install premium tankless water heaters at a published, all-in price. No surprise fees. No high-pressure upsells. Your old tank out by noon, endless hot water by dinner.

3,895$
Starting, all-in
1day
Install time
15yr
Heat exch. warranty
$1,400
Avg. rebates
Rinnai Certified
Permit handled
Your estimate
4BR · Rockville, 20850
LIVE
Signature — Navien NPE-240A210.1 GPM
Fixed install price$5,295
Washington Gas rebate−$450
MD manufacturer rebate−$100
Federal tax credit (30%)−$600
Montgomery Co. tax credit−$250
Your net price $3,895
Rinnai Certified
Navien Specialist
Washington Gas Partner
MD Master Plumber
WSSC Approved
MHIC Licensed
Rheem Pro Partner
Energy Star Contractor
Rinnai Certified
Navien Specialist
Washington Gas Partner
MD Master Plumber
WSSC Approved
MHIC Licensed
01 / Why switch

Your tank heater is failing you — in eight quiet ways.

The 50-gallon tank in your Rockville basement is a 1950s invention, burning gas 24 hours a day to keep water hot you aren't using. There's a better way, and Montgomery County homes are built for it.

01 · Cold shower
It always fails on a Monday morning.

Tanks typically die during peak use. A tankless system heats water on demand — nothing to rust, corrode, or flood your finished basement at 3am.

02 · Teenagers
Two showers, cold finish.

Your 50-gal tank holds one family bath. A properly sized Navien NPE-240A2 delivers 10.1 GPM — that's two showers + laundry + dishwasher, forever.

03 · Standby loss
$95/yr heating water you never use.

Washington Gas estimates a family of four saves up to $1,800 over the unit's lifetime with a tankless vs. a standard natural gas storage model.

04 · Basement flood
4 square feet, gone.

A wall-mounted tankless reclaims the corner of your utility room. Built-in leak sensors and no tank = no $10K water-damage claim on your homeowners insurance.

05 · Opaque pricing
We're the only ones who publish prices.

Call three Montgomery County plumbers, get quotes of $2,400 to $7,800 for the same job. We publish three fixed tiers with full scope & terms.

06 · Permit anxiety
Rockville requires a permit. We pull it.

Skipping permits bites at resale and voids insurance claims. We handle Montgomery County permit filing and inspection scheduling — baked in.

07 · Lifespan
10 years vs. 20+ years.

Tank heaters last 10–15 years at best. Tankless units routinely run 20+ years with annual flushes. One replacement instead of two in your tenure.

08 · Hard water
Rockville water is hard. We plan for it.

Rockville water comes from the mineral-rich Potomac. Standard tanks corrode fast here. Our installs include descaling service valves + first-year flush included.

— The math
Year 1: saves $200. Year 15: saves $4,200+.

Energy savings, one-time rebates, deferred replacement, extended warranty, reclaimed floor space. A tankless pays for itself twice.

02 / Fixed pricing

Three tiers. One price. No surprises.

Every tier includes the unit, removal, permit, standard venting, standard gas connection, condensate tie-in, initial flush kit, and rebate paperwork. See our full pricing page for complete scope & terms — no hidden add-ons.

Essential
Proven condensing gas
Rinnai RE140iN or Navien NPE-180S. Right-sized for 2–3 bath homes.
$3,895all-in
• As low as $2,745 after rebates
~8.0 GPM
  • Like-for-like gas swap
  • 15-yr heat exchanger warranty
  • Montgomery County permit included
  • Up to 20 ft standard venting
  • Old tank haul-away
  • First-year flush service included
  • All rebate paperwork filed
Book free consult →
Whole-Home Pro
Max flow for large homes
Navien NPE-320A2 or dual-unit config for 4+ bath homes.
$7,495all-in
• As low as $6,345 after rebates
~12+ GPM · Max output
  • Everything in Signature
  • Commercial-grade heat exchanger
  • 3 showers + full laundry + dishes
  • Advanced Wi-Fi + diagnostics
  • 3-yr labor warranty
  • Same-week install priority
Book free consult →
03 / How it works

From first call to first shower — four steps, about ten days.

We designed this around how long it actually takes the Montgomery County permit office to turn around paperwork. Your install day itself is a single, clean visit.

01st
Instant estimate online

Six questions. Thirty seconds. You'll see your fixed tier, rebate estimate, and financing options before you even pick up the phone.

Time: 30 sec
02nd
Free in-home consult

A licensed master plumber verifies gas sizing, venting path, and every item on our scope sheet. You get a final, locked-in quote on the spot — no back-office callback.

Time: 45 min
03rd
We pull the permit

Montgomery County permit, WSSC coordination, utility scheduling — all handled. You pick a Tuesday or Wednesday install day.

Time: 5–7 days
04th
Install in one day

Old tank out by noon. New tankless wall-mounted, gas + water + vent + condensate tied in, commissioned, and flushed. Hot showers by dinner.

Time: 6–8 hrs
04 / Instant estimate

Skip the call. Price your install in thirty seconds.

Answer six quick questions and we'll show you your tier recommendation, fixed price, and stacked rebates — before we ever speak.

How many bathrooms?

We use this to size your tankless — GPM needs scale with simultaneous fixture demand.

1 / 6

Your estimate will appear here.

Answer six quick questions on the left. We'll calculate your tier, stacked rebates, and monthly financing options in real time — no email required to see it.

05 / Tank vs. Tankless

A head-to-head you can actually use.

No marketing fluff. Real numbers from Washington Gas, Energy Star, and 200+ installs we've completed in Montgomery County. Full breakdown on the tank vs. tankless page.

Traditional tank heater

50-gal · gas · storage
Lifespan10–15 yrs
Hot water capacity~50 gal, then 30 min recovery
Floor space required~4 sq ft
Annual gas cost (family of 4)~$280/yr
Standby heat lossYes — 24/7
Flood risk at failureHigh (50 gal)
15-yr total cost of ownership$7,200+

Tankless on-demand

Navien NPE-240A2 · condensing
Lifespan20+ yrs
Hot water capacityEndless · up to 10.1 GPM
Floor space required~0 (wall-mount)
Annual gas cost (family of 4)~$185/yr
Standby heat lossNone
Flood risk at failureMinimal (no tank)
15-yr total cost of ownership$5,800 (after rebates)
06 / Brands we install

Three brands. Not thirty.

Every plumber claims to "work on all brands." We only install the three that earn their premium — the ones with parts availability, warranty support, and long-term reliability we'd put in our own homes.

NAVIEN
South Korea · Since 1978

Industry leader in condensing tankless. NPE-A2 series includes built-in recirc pumps — a feature others charge extra for. Best for homes wanting instant hot water everywhere.

15yr
Warranty
0.96
UEF max
11.2
Max GPM
RINNAI
Japan · Since 1920

The reliability benchmark. Simpler to service than Navien, with exceptional heat exchanger longevity. RX series is our pick for homeowners who want "set and forget" for two decades.

15yr
Warranty
0.96
UEF max
11.0
Max GPM
RHEEM
USA · Since 1925

Best-value tankless with strong US parts network. The Prestige line matches Navien and Rinnai on efficiency, with slightly lower upfront cost. Ideal for budget-conscious buyers.

12yr
Warranty
0.95
UEF max
9.5
Max GPM
07 / Where we install

Ten ZIPs. That's our whole service map.

We stay small, stay local. Every tech lives within 20 minutes of your home — so when we say same-week install, we mean it. Click any city to see local pricing and rebate detail.

"

Every other plumber wanted to come out, poke around my basement, and then call me back with a number. DMV Tankless gave me the fixed price on their site — $5,295 — and that was the exact number I paid. Install took one day. Hot water hasn't dropped once since.

★ ★ ★ ★ ★
Priya N., Rockville 20852
Navien NPE-240A2 · Installed March 2026
08 / Reviews

200+ installs. 4.9 stars. Zero callbacks.

We publish every review we get — including the 4-stars. See all 200+ on our reviews page.

★★★★★

"Three quotes from other Montgomery County plumbers ranged from $4,200 to $7,800 for the same scope. DMV Tankless told me $5,295 on their website. That's what I paid. Showed up Tuesday, done by 3pm."

M
Michael T.
Potomac · 20854
★★★★★

"What I appreciated most: they actually pulled the Montgomery County permit. Previous contractor didn't, and I had issues when I tried to refinance. DMV Tankless handled everything — inspection, sign-off, rebate paperwork."

K
Kristen W.
Gaithersburg · 20878
★★★★★

"My family of six was running out of hot water daily with the old 50-gal tank. They installed the Navien 240A2 with recirculation. Three showers going, dishwasher running, nothing drops. Should have done this years ago."

R
Ravi S.
Bethesda · 20817
09 / Common questions

The honest answers.

Nothing buried. See the full FAQ for 40+ more.

How much does a tankless water heater cost in Rockville, MD?

+

Our fixed tiers are $3,895 (Essential), $5,295 (Signature with recirculation), and $7,495 (Whole-Home Pro for 4+ bath homes). All prices are all-in — unit, permit, standard venting, gas/water/condensate connections, old-tank haul-away, and all rebate paperwork. Most Montgomery County homeowners qualify for $1,150–$1,400 in stacked rebates, dropping the net price accordingly.

How long does a tankless water heater installation take?

+

One day — typically 6–8 hours from arrival to commissioning. We arrive around 8am, the old tank is out by noon, and by mid-afternoon the new unit is mounted, gas/water/venting/condensate are all connected, the system is flushed and pressure-tested, and you're ready for a hot shower by dinner. From your first consult to install day is usually 8–12 days, most of which is Montgomery County permit processing.

Do I need a permit to install a tankless water heater in Montgomery County?

+

Yes. Both the City of Rockville and Montgomery County require permits for water heater replacement and any conversion from tank to tankless. Skipping the permit voids homeowners insurance coverage for related water damage and creates issues at resale. We pull the permit, schedule inspection, and hand you the signed card — it's included in the fixed price.

What rebates can I get for a tankless water heater in Maryland?

+

Natural gas customers in Montgomery County 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. Total stackable savings reach $1,400 for qualifying Energy Star units. We file every form on your behalf.

Is a tankless water heater worth it in Maryland?

+

For most Montgomery County homes with 3+ bathrooms or 3+ occupants — yes. You'll save roughly $95–$200/year on gas (Washington Gas figures), get 20+ year lifespan vs. 10–15 for tanks, reclaim 4 sq ft of floor space, and eliminate basement flood risk. Factor in ~$1,400 in rebates and a 15-year total cost of ownership that's lower than a tank, and the math works out favorably for most homeowners.

What brands do you install?

+

We install three brands only: Navien, Rinnai, and Rheem. These are the brands with the best parts availability in the DMV, strongest warranty support, and proven 20+ year reliability. We decline to install off-brand tankless units even when requested — we won't install what we can't stand behind.

Ready for endless hot water?

Book your free 45-minute in-home consult. A licensed master plumber will verify sizing, lock your fixed price, and answer every question. Zero commitment.

Most consults booked within 72 hours. No credit check. No deposit.
72h
Avg. to consult