In this guide
Homeowners want a number before you start. Plumbing makes that hard, because half the job is behind a wall. The way through is to flat-price the jobs you can see all of (a water heater, a toilet, a disposal), put hourly limits on the ones you can't (a slow drain, a leak you haven't found), and build every flat price from the same parts, so it holds up when costs move.
A flat price, worked through
A 50-gallon gas water heater swap, like for like, in a basement with good access:
| Part | How it's figured | Amount |
|---|---|---|
| Labor | 3 hours at a $125 billable rate | $375.00 |
| Water heater | $900 at cost, plus 20% | $1,080.00 |
| Parts | Expansion tank, valves, fittings and flue parts, $85 at cost, plus 25% | $106.25 |
| Haul-away | Disposal of the old tank | $60.00 |
| Trip | Drive time, fuel and truck for the visit | $85.00 |
| Flat price | $1,706.25, rounded to $1,710 | |
| Permit | Passed through at cost, on its own line | varies by city |
- Why the markup on the heater is lower
- Big-ticket equipment usually carries a smaller percentage markup than small parts, because the dollars are larger and clients can look up the price. Twenty percent on a $900 heater is still $180 of margin, and it covers the pickup, the warranty paperwork and the risk of a unit that arrives damaged.
- The billable rate covers more than the wrench time
- $125 an hour has to pay for driving, estimates and the hours nobody bills, plus insurance and the truck. The labor cost calculator works out what yours needs to be.
Adjust for what makes it harder
Price books handle hard access with a surcharge, not a new job: an attic or closet install, a tight crawlspace, a code upgrade the old install didn't have (an expansion tank, a drip pan, venting). Name the surcharge on the estimate. "Includes code-required expansion tank" tells the client why your number is higher than the one they found online.
Know when to use the clock
Drain cleaning, leak detection and older homes go by the hour, or a flat first hour with a not-to-exceed amount for the rest. You don't know what's down there until you're in it, and a flat price either scares the client or loses you money.
After-hours and emergency work carries a multiplier, commonly 1.5 times the standard rate, stated before the visit and shown on the invoice line: "emergency call after 6 pm, 1.5x".
Client-supplied fixtures get labor only, with the warranty terms written down: "faucet supplied by owner, labor warranty only".
Check your price book twice a year
Equipment prices move, and so does your time. Every six months, pull your last few jobs of each type and compare the hours and parts against the book. The job profit calculator shows each job's real margin, and the plumbing invoice template and estimate template carry the lines above.
For wage context, the Bureau of Labor Statistics publishes median pay for plumbers. That's a wage, not what a plumbing business needs to bill.
When a property manager sends the job, the work order template records their PO number and the not-to-exceed amount, and a fixed-price job can go out on the quote template with a line for the client's acceptance.
What did that job really make?Profit and margin for any job in seconds.FAQ
Is flat-rate pricing better than hourly for plumbers?
For predictable jobs, usually yes. Clients like a fixed number, and you're rewarded for efficiency. For diagnostic and hidden-condition work, hourly with a cap is fairer to both sides.
How much should a plumber charge for a trip?
Enough to cover the drive time, fuel and truck cost of a typical visit on your routes. Work it out from your own numbers, then either show it as a line or build it into every flat price.
Should plumbers mark up parts?
Yes. The markup pays for sourcing, stocking, returns and warranty. It's common to use a lower percentage on expensive equipment and a higher one on small parts.
