Gas tankless water heater replacement cost in Washington, DC
Installed, About 180,000–199,000 BTU (2–3+ bathrooms)
A typical tankless water heater (About 180,000–199,000 BTU (2–3+ bathrooms)) costs about $2,850 installed in the Washington area, 2% above the national figure, because plumbers here earn a median $35 an hour against $31 nationally.
Prices by size in Washington
| Size | Low | Typical | High | National typical |
|---|---|---|---|---|
| About 150,000 BTU (1–2 bathrooms) | $2,100 | $2,700 | $3,600 | $2,650 |
| About 180,000–199,000 BTU (2–3+ bathrooms) | $2,600 | $2,850 | $3,950 | $2,800 |
Local labor: what plumbers earn here
| Hourly wage | Washington metro | United States |
|---|---|---|
| 25th percentile | $27 | $24 |
| Median | $35 | $31 |
| 75th percentile | $45 | $41 |
The Washington market
In the District, the Department of Buildings (DOB) says new and replacement gas appliances and new and replacement HVAC equipment need a permit. Only DC contractors licensed in the specific trade may apply, and a Mechanical Instant Permit, which covers installing one new air conditioning unit up to 10 tons, can only be issued to licensed contractors. You schedule a DOB inspection once the work is done, and a permit goes invalid if it has no approved inspection within 12 months. The fee schedule lists $36 for the first furnace, $65 for the first residential central AC system up to 5 tons and a $20 minimum plus 10%. Row houses with boilers and radiators are common: EIA found boilers provide main heat in 22% of DC homes and heat pumps in 14%. Arlington, Alexandria and the Maryland suburbs follow their own county rules.
Row houses often have little room for venting, so a gas tankless unit may need a new sidewall termination that clears windows and neighbors' openings, which can rule out some locations. Ask the plumber to show where the vent will exit and whether the existing gas line can carry the higher input. A wall-hung unit does free up space in a cramped basement.
Permits in Washington
| Permit for this job | Gas only (confirmed: 'new and replacement gas appliances' need a permit); electric unclear (source) |
|---|---|
| Fee | Itemized: furnace or unit heater $36 first, $16 each additional; central AC up to 5 tons (residential) $65 first; plumbing fixture $26 first, $20 each additional; minimum permit fee $20 (+10% = $22). Instant permit fees 'average $36.30'. |
| Who can pull it | Licensed DC trade contractor only for plumbing/mechanical trade permits |
| Inspection | Yes |
Rebates in District of Columbia
HEAR: open with limits. HOMES: status unclear. Source: DC Department of Energy & Environment (DOEE), checked October 13, 2026.
- DC Sustainable Energy Utility residential rebates: Heat pump, HPWH and HVAC rebates at any income ('up to $5,000 off electric equipment' enhanced rebates)
What these programs cover, and other states
Other systems in Washington
- Gas tank water heater
- Gas furnace
- Central air conditioner
- Heat pump (ducted, outdoor unit + air handler)
Gas tankless water heater cost in other metros
Sources
- DC DOB: What projects require a permit
- DC DOB: Mechanical Instant Permits
- DC DOB permit fee schedule
- DC Sustainable Energy Utility: residential rebates
- DCSEU: Affordable Home Electrification Program
- EIA, 2020 RECS: Highlights for space heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for water heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for air conditioning in U.S. homes by state
- BLS OEWS May 2025, Washington-Arlington-Alexandria, DC-VA-MD-WV (47-2152 plumbers)
- DOE Gas-fired Instantaneous Water Heaters Final Rule TSD (Dec 2024), Table 8.2.6 (2023$)