How to Estimate a Plumbing Job: A Contractor's Guide
Plumbing estimates go wrong in two directions: you underprice and work for free, or you overprice and lose the bid. The fix is a consistent estimating process — one that accounts for every fixture, every foot of pipe, every access challenge, and every permit. Here's how to do it right.
Start With a Complete Scope of Work
Never quote a plumbing job from a text message or a quick phone call. Walk the job. What you're looking for:
- Fixture count — toilets, sinks, showers, tubs, dishwasher, ice maker, hose bibs
- Water heater — gas or electric? Tank or tankless? Replacing or new install?
- Supply lines — copper, PEX, CPVC? Existing material and condition?
- Drain, waste, and vent (DWV) — cast iron, ABS, PVC? Any re-routing needed?
- Access — crawl space, slab, open framing, or finished walls?
- Shutoffs — are they working? Do they need to be replaced?
- Permit — required for most rough-in and water heater work
Access is the biggest variable in plumbing. A toilet replacement in an open bathroom costs 1 hour. The same job with a corroded shutoff, an offset flange, and a finished wall that needs to be opened could cost 4.
Unit Pricing for Common Plumbing Work
For service and repair work, unit pricing keeps your estimates fast and consistent:
| Item | Unit Price Range |
|---|---|
| Toilet replacement (standard) | $350–$600 |
| Faucet replacement (standard) | $200–$400 |
| Garbage disposal install | $250–$400 |
| Dishwasher supply/drain hookup | $150–$300 |
| Water heater — 40 gal gas (replace) | $1,200–$2,000 |
| Water heater — 50 gal gas (replace) | $1,400–$2,200 |
| Tankless water heater (gas) | $2,500–$4,500 |
| Hose bib replacement | $200–$350 |
| Shutoff valve replacement | $150–$250 |
| Main shutoff replacement | $300–$600 |
| Sewer line cleaning (standard) | $200–$400 |
| PRV (pressure reducing valve) | $400–$700 |
These are installed prices — material + labor + overhead. Adjust for your market.
Labor + Material Estimating for Larger Jobs
For remodels, additions, and new construction rough-in, break it down:
Typical Labor Times
| Task | Time (journeyman) |
|---|---|
| Toilet rough-in and set | 2–3 hrs |
| Sink rough-in (supply + drain) | 2–3 hrs |
| Tub/shower rough-in | 4–6 hrs |
| Water heater replacement | 2–4 hrs |
| PEX supply rough-in per fixture | 1–2 hrs |
| DWV rough-in per fixture | 2–4 hrs |
| Slab penetrations (per hole) | 1–2 hrs |
Plumber labor rate (US, 2024–2025): $80–$140/hr depending on region and license level
Material Pricing
| Material | Price Range |
|---|---|
| PEX-A pipe (½") | $0.50–$0.90/ft |
| PEX-A pipe (¾") | $0.80–$1.20/ft |
| Copper pipe (½") | $2.50–$4.00/ft |
| PVC drain pipe (3") | $1.00–$1.80/ft |
| PVC drain pipe (4") | $1.50–$2.50/ft |
| Ball valve (½") | $15–$30 |
| SharkBite fitting (½") | $8–$15 |
| Wax ring | $8–$15 |
| Toilet flange | $15–$30 |
Mark up materials 20–35%. Your supplier discount is your margin, not the client's discount.
Sample Estimate: Bathroom Remodel Rough-In
Scope: new bathroom addition — toilet, sink, tub/shower combo. Slab foundation, open framing.
| Line Item | Qty | Unit | Rate | Total |
|---|---|---|---|---|
| Slab penetrations (3) | 3 | each | $175 | $525 |
| DWV rough-in — toilet | 1 | fixture | $425 | $425 |
| DWV rough-in — sink | 1 | fixture | $350 | $350 |
| DWV rough-in — tub/shower | 1 | fixture | $550 | $550 |
| Supply rough-in — PEX ¾" main | 30 | ft | $2.20 | $66 |
| Supply rough-in — PEX ½" branches | 60 | ft | $1.60 | $96 |
| Supply fittings and manifold | 1 | lot | $180 | $180 |
| DWV pipe, fittings, hangers | 1 | lot | $320 | $320 |
| Shutoff valves (4) | 4 | each | $28 | $112 |
| Permit | 1 | job | $350 | $350 |
| Labor — plumber (18 hrs @ $110) | 18 | hr | $110 | $1,980 |
| Subtotal | $4,954 | |||
| Overhead & profit (20%) | $991 | |||
| Total | $5,945 |
Sample Estimate: Water Heater Replacement (50 gal Gas)
| Line Item | Qty | Unit | Rate | Total |
|---|---|---|---|---|
| 50-gal gas water heater (A.O. Smith) | 1 | each | $780 | $780 |
| Supply lines (flex) | 2 | each | $18 | $36 |
| Dielectric unions | 2 | each | $22 | $44 |
| T&P relief valve + drain line | 1 | job | $45 | $45 |
| Gas flex connector | 1 | each | $25 | $25 |
| Haul-off old unit | 1 | job | $75 | $75 |
| Labor — plumber (3 hrs @ $115) | 3 | hr | $115 | $345 |
| Permit (if required) | 1 | job | $150 | $150 |
| Subtotal | $1,500 | |||
| Overhead & profit (20%) | $300 | |||
| Total | $1,800 |
What Kills Plumbing Profit Margins
Underestimating access difficulty. Finished walls, low crawl spaces, and slab work cost 2–3× more than open framing. Always note access conditions during the walkthrough.
Forgetting permit and inspection time. Rough-in permits require inspections, which means scheduling around the inspector's availability. That's time.
Not pricing drain cleaning as a separate line. If you're doing a fixture replacement and the drain is slow, that's a separate service with its own charge — not something you do for free because you're already there.
Material price changes. Copper, PEX, and fixture prices fluctuate. Update your pricing before proposal season.
Not writing a scope statement. "Bathroom plumbing" means different things to different people. Write out exactly what's included and what's excluded.
Bid.Fast lets you record a voice walkthrough of a plumbing job and generate a complete itemized estimate in 90 seconds. Walk the job, talk through it, and send a professional quote before you even leave the driveway.
Try 3 free plumbing estimates →
Bid.Fast is a voice-to-estimate app built for plumbing contractors. Start free →