Ask the question in any plumbers' forum and the thread splits within ten replies. Some shops refuse customer-supplied fixtures outright and lose the jobs that come with them. Some take everything and quietly eat the missing parts and the unpaid return trips. The shops that handle it well do neither. They treat a customer-supplied install as its own job type with its own rate and its own paper, and they decided all of it before the phone rang. This guide lays that policy out: what the labor price has to carry when there is no parts margin under it, where the warranty boundary sits, what happens when the supplied fixture is wrong, and how the whole thing reads on the quote so the doorstep conversation never happens.
The short answer: install them, on your terms, on paper
Take the jobs. A customer who bought their own faucet has already committed to the project, has already spent money on it, and is calling you to finish it. That is a warmer lead than most, and turning it away sends it to whoever answers next. What you may not do is treat it as the same job as an install where you supplied the fixture, because three things changed when the customer went shopping. Your parts margin left the job. The risk that the fixture is wrong or incomplete moved onto your schedule without moving onto your invoice. And the fixture's warranty now belongs to the customer, not to you, which matters more than most operators realize when the callback comes.
So the policy is one sentence long: yes, at a labor-only rate set for this job type, with the warranty scope and the wrong-fixture terms stated on the quote. The rest of this guide is what each clause costs you when it is missing.
Why customer-supplied jobs feel cheaper and bill worse
The customer who supplies their own fixture believes they are saving money, and from their side of the receipt they are. They paid the store price instead of your marked-up price, and they expect the install to cost less too, since you are "just putting it in." That expectation is the trap. On a normal install, part of what pays for your time never appears as labor at all. It rides in the parts line: you buy at the supply house, bill at retail, and the spread helps carry the truck and the license, and it pays you for knowing which fixture fits the rough-in that is already in the wall. Hand the shopping to the customer and that spread is gone, but the truck and the license still cost what they cost.
The job also gets harder, not easier. A fixture you supplied is one you have installed before, bought from a counter that will swap a bad one in minutes. The fixture in the customer's box is a mystery until you open it. It may be missing the tailpiece or the supply lines. It may be the wrong rough-in for what is in the wall. It may be a model you have never seen, with an instruction sheet translated twice. None of that is the customer's fault as they see it, and all of it lands on your clock. A job with less billable material and more unbillable uncertainty cannot also carry a discount. Priced honestly, the labor on a customer-supplied install should cost the customer more per hour than the labor on a job you supplied, and the next section is how to get there without an argument.
Price the labor like you lost the parts margin, because you did
Start from your cost floor, not from what the customer hoped. The median wage for plumbers, pipefitters, and steamfitters is about $62,970 a year, roughly thirty dollars an hour, and that is an employee wage before payroll burden, insurance, the stocked van, and the unbillable windshield time that wraps every service call.2 By the time a licensed plumber is kneeling under a sink, the loaded cost of that hour is a multiple of the wage. On a normal install, your labor rate plus your parts margin clears that cost together. On a customer-supplied install, the labor rate is alone on the job, so it has to clear the whole bar by itself.
The clean way to do this is a separate line item in your price book: "install customer-supplied fixture," priced above the labor on an equivalent supplied install. How far above depends on your own markup structure, which is a decision covered in how much contractors should mark up materials. The point is not the exact spread. The point is that the number was set in the shop, on purpose, instead of improvised at the door under the gaze of a customer holding a receipt from the big-box store. A rate that exists as a named line in your price book is a policy. A rate you make up on the doorstep is a negotiation, and doorstep negotiations run one direction.
Do not bury the difference. If the customer asks why the install costs more than the number their neighbor paid, the honest answer is also the persuasive one: when you buy the fixture from us, part of what you pay for the fixture pays for the install. When you bring your own, the install price has to stand on its own. Most customers accept a plain explanation of how the price works. What they do not accept is discovering the difference on the invoice.
The warranty line that keeps the callback off your tab
This is the clause that decides whether a customer-supplied job you priced right in August turns unprofitable in December. When the fixture fails, and some will, the customer's first call is to you, because yours is the only name they associate with the sink. Without a written boundary, that call becomes a free return visit, and the free return visit erases the margin on the original job and then some.
The boundary is worth stating precisely: you warrant the installation, not the fixture. If the joint you made weeps or the connection you threaded leaks, that is your workmanship, and you fix it free, promptly and without quibbling, exactly as you would on any job. If the cartridge fails, the finish pits, or the sprayer head splits, that is the fixture, and the fixture is the customer's property under the customer's warranty. This is not you dodging responsibility. It is how the manufacturers themselves draw the line. A major fixture maker's limited warranty runs to the original consumer purchaser, ships replacement parts free of charge, and states outright that the maker is not responsible for labor charges incurred in installation, repair, or replacement.1 In other words, when the supplied faucet fails, the manufacturer will mail your customer a part and nobody in that transaction is paying for your return trip. Either the customer pays for the visit, or you do. The warranty line on the quote is what decides which, and it should be written before the first visit, not argued after the second.
There is a second, quieter reason the line matters. Because the manufacturer's warranty belongs to the purchaser, a fixture you supplied is one you can claim on, swap at the counter, and stand behind without much risk. A fixture the customer supplied gives you no such standing. You cannot honestly extend your name over a product you did not pick and cannot exchange. How long your own workmanship term should run, and how to sort a callback into your warranty, a new failure, or customer-caused damage, is its own decision, covered in how long a plumbing warranty should be. For this job type, the scope line comes first: labor-only, in writing, on the quote.
The wrong-fixture trip charge
The most common way a customer-supplied job goes sideways is not a failure. It is a box. You arrive, open it, and the faucet is missing its supply lines, or it is a single-hole model over a three-hole sink, or the "new" disposal is the returned unit someone taped back up. The visit is over before it starts, and without a stated policy, it is over at your expense: an unbillable hour, a burned slot on the route, and a customer who now wants you to swing by the store on the way back.
The fix is a stated trip charge for exactly this case, quoted up front alongside the install price: if the supplied fixture turns out to be wrong or incomplete when I arrive, the visit bills at this amount, and we reschedule once the right fixture is on site. Said before the job, it is a reasonable term nobody fights, and it quietly motivates the customer to check the box before you drive out, which is the outcome you wanted anyway. Two companion rules belong beside it. You do not make sourcing runs on your own time; if the customer wants you to go get the right part, that is billable time and a marked-up part, like any other job. And rescheduling happens at the route's convenience, not as an emergency, because the emergency was avoidable and was not yours.
Put the policy on the quote, not in the doorway argument
Every clause above is a sentence the customer should read before you arrive. Not because customers study quotes, but because the quote is what settles the conversation later, when memory gets convenient. The quote for a customer-supplied install carries a named line for the work: not "install faucet," which invites comparison to every number the customer has ever heard, but "install customer-supplied kitchen faucet, labor only." Below it, the warranty scope in one sentence: installation workmanship warranted for your stated term; the fixture itself is covered by the manufacturer's warranty held by the customer. Below that, the wrong-fixture terms: the trip charge, the sourcing rule, the reschedule rule.
A customer who approves that quote has agreed to the price and every boundary around it in one signature, and the install visit starts with everything already settled. The same structure should survive onto the invoice, which is where disputes get settled: the labor line, the warranty scope, and, if the box was wrong, the trip charge the customer already agreed to. What belongs on that document line by line is covered in what to put on a plumbing invoice. The pattern underneath is the same one that runs through every pricing decision in this trade: the policies that protect you are the ones the customer saw in writing before the work started.
A worked example: the same faucet, supplied two ways
The numbers below are illustrative, chosen to show where the money moves. Use your own rates and your own markup.
A customer wants a mid-range kitchen faucet replaced. If your shop supplies it: you buy the faucet at the supply house for $180 and bill it at $260, and the install labor is $195. The quote totals $455. Inside that number, the $80 parts spread and the labor line are carrying the job together, and if the faucet is defective out of the box, you swap it at the counter and the customer never knows.
Same sink, but the customer bought their own faucet for $230 at the big-box store. Your quote reads: install customer-supplied kitchen faucet, labor only, $265. Warranty: installation workmanship for one year; the fixture is covered by the manufacturer's warranty held by the customer. If the supplied fixture is incomplete or incompatible on arrival, the visit bills at $85 and we reschedule. The customer pays $265 instead of $455 and feels the savings they went shopping for. You bill $70 more than the bare labor on the supplied version, which is the parts margin the job no longer carries, priced back into the only line left. Both sides got what they came for, and every term either of you might need later is already in writing.
Now run the failure. Eight months in, the sprayer head splits. On the shop-supplied faucet, you claim the part under the warranty you effectively control and decide for yourself whether the goodwill visit is worth it. On the customer-supplied faucet, the manufacturer mails the customer a replacement head free of charge, the labor exclusion in the warranty means nobody upstream is paying for the swap, and your quote already said whose job that is.1 The return visit is a small billable job instead of an argument. That is the whole policy working: not a single dramatic save, just a job that stayed profitable at every point where the unpriced version would have leaked.
Put the policy on the quote once, reuse it on every job
We built EosLog's quote generator so a plumber can save the customer-supplied install as its own line item, with the labor-only price, the warranty scope, and the wrong-fixture terms already worded, and drop it into any quote in a few seconds. The customer signs from their phone, and the terms ride along to the invoice.
Try the free plumbing quote generator
No account required. You can also create a free EosLog account to save your customer-supplied policy wording and reuse it on every quote, or see the plans first.
Sources and further reading
- Moen Incorporated, Warranty Information for Moen Faucets, Lifetime Limited Warranty (warranty runs to the original consumer purchaser; replacement parts provided free of charge; "Moen will not be responsible for labor charges and/or damage incurred in installation, repair or replacement").
- U.S. Bureau of Labor Statistics, Occupational Outlook Handbook, Plumbers, Pipefitters, and Steamfitters (median annual wage $62,970 in May 2024, about $30 per hour; used here as an employee-wage baseline for loaded-cost math, not a billed rate).
This guide reflects general US residential plumbing practice as of 2026 and is not legal or pricing advice. Rates, warranty conventions, and consumer-protection rules vary by state and market, and every dollar figure in the worked example is illustrative. Set your install rate and trip charge from your own costs, and confirm any disclosure requirements your state applies to service pricing and warranty terms.