Cost · Potomac, MD · Montgomery County
What Plumbing Work Costs in Potomac, MD: Wide Ranges and What Moves Them
Planning ranges for nine common jobs, what moves each one and what to ask before saying yes. Ranges are not quotes.
Planning ranges for nine common jobs, from national guides
These ranges are for planning only. They come from national price guides and a Maryland tank replacement average, checked in October 2026. No Potomac-specific price list exists to cite, so the figures are wide on purpose, and any job can land outside them.
A written quote after the plumber sees the house is the only real price.
| Job | Wide planning range | What moves the price | More detail |
|---|---|---|---|
| Tank water heater replacement | $800 to $2,800 | Tank size, gas or electric venting, expansion tank and permit and inspection for gas units. | tank heater replacement |
| Tankless water heater installation | $1,400 to $4,800 | Gas line sizing, electrical panel capacity and the exterior venting route. | tankless installation |
| Drain cleaning with a cable | $100 to $800 | Cleanout access and whether the clog sits in a sink branch or the main line. | drain cleaning |
| Hydro jetting a main sewer line | $350 to $1,000 | Footage of pipe, roots against grease and cleanout access. | jetting a main sewer line |
| Slab leak detection and spot repair | $600 to $4,500 | Detection time, foundation depth and whether the fix is a breakout or an overhead reroute. | slab leak detection |
| Trenchless sewer pipe lining | $1,900 to $8,500 | Footage lined, pipe diameter and the condition of the old pipe. Long runs can pass the top of the range. | sewer pipe lining |
| Whole-house repiping with PEX | $4,000 to $12,000 | Square footage, bathroom count and how much drywall must open. | PEX repiping |
| Garbage disposal replacement | $100 to $550 | Motor horsepower, outlet access and the sink flange type. | disposal replacement |
| Gas line repair or short extension | $150 to $1,400 | Length of the pipe run, pressure testing and the appliance connection. Buried runs cost more. | gas line work |
A 2025 HomeServe guide puts the Maryland average for a tank replacement in the middle of the first range, which fits that row. Treat every row as a starting point for questions and not a number to hold a plumber to.
What pushes a Potomac quote up or down
The same job costs different amounts from one house to the next. Five local factors explain most of the gap.
- Line length. Potomac lots run large, so a service line or sewer lateral can be long. More pipe means more labor and more material.
- Access. An open basement ceiling is cheaper to work in than a finished one, and a slab is dearer than a crawl space.
- Permits and inspections. WSSC issues the permit and inspects gas work, and only a WSSC-registered master plumber may dig or repair underground sewer pipe. Both add steps that belong in the quote.
- Fuel and venting. Gas, electric and propane units need different connections, and a tankless heater may need a bigger gas line.
- Hard water. WSSC reports Potomac River water averaging about 120 to 130 mg/L of hardness. Scale shortens heater life and complicates old fixtures.
None of these show up in a phone estimate, which is why ranges are wide. A plumber who has walked the line can narrow them.
Jobs we price only after someone sees the scope
Some work has no honest range because the scope is unknown until someone looks. We give no figure for these jobs until someone has seen the scope.
- leak location work, which depends on how hard the leak is to find
- emergency pipe repair, which depends on the pipe, the access and the hour
- restoration scope, priced by the area dried and the days of equipment
- toilet work and faucet and sink work, where parts and the fixture chosen set the price
Ask for the scope in writing for any of these, then compare it with a second plumber's scope and not just the total.
Where a quote can leave out costs
Two quotes for the same job can differ by hundreds because one leaves things out. Read each line for the items below.
- Permit and inspection fees, which apply to gas work and underground sewer repair.
- Patching drywall, tile or flooring that had to open for access.
- Restoring grass, a driveway edge or a walkway after digging.
- Hauling away the old heater, pipe or fixture.
- A new shutoff valve, a pressure regulator or an expansion tank added to the job.
- Any extra charge tied to the time or day of the visit.
A line that says "as needed" is a gap in the quote. Ask what it means in plain terms and what it could add. Written answers protect both sides if the scope changes midway.
What to ask before agreeing to a price
- Is the quote in writing, with the work described in plain terms?
- Does it include the permit and the inspection, and who books them?
- What is the plumber's WSSC license number? WSSC confirms it at 301-206-8588.
- Is removal of the old unit or pipe included?
- What happens to the price if the plumber finds something else behind the wall?
- Which parts and labor carry a warranty, and for how long, in writing?
A plumber who answers these without hesitation has usually done the job before. The questions about quotes and permits cover the rules behind several of them.
Repair or replace: how cost changes the decision
A repair that costs more than half of a replacement is a signal to compare both. The comparison is different for each system.
For a tank heater, look at the age, the leak location and the hardness of the water before choosing repairing the heater first over a new tank. A leak from the tank itself ends the debate.
For supply piping, one leak in sound pipe is a repair, while leaks that keep appearing point toward a repipe. Ask the plumber to show the pipe, not just describe it.
Want a plan before a price?
Describe the problem and give your address. A plumber scopes the job and quote it in writing.