Every plumber learns the same lesson the expensive way. A job goes sideways, the customer says “that is not what we agreed to,” and you have nothing in writing except a text thread and a number scribbled on an estimate. A real plumbing contract template fixes that in about ten minutes of setup, and then it works for you on every job after.
This is what actually belongs in one, in plain language, with the wording you can lift straight into yours.
Estimate, contract, invoice: three different documents
People mix these up constantly, and it costs them.
- Estimate or proposal. What you think the job will cost. Not binding until someone signs it. This is a sales document.
- Contract. The signed agreement. Scope, price, timeline, payment terms, what happens when things change. This is your protection.
- Invoice. The bill after the work. It should reference the contract, not restate it. If you need a starting point, grab our plumbing invoice template.
On small service calls, one signed work authorization can do the job of all three. On anything over a couple thousand dollars, or anything that takes more than a day, you want a separate contract.
The 12 things every plumbing contract needs
1. Both parties, spelled out
Your legal business name (not your DBA nickname), address, phone, license number, and the customer legal name and the property address. If the billing address is different from the job address, list both. If you are working for a GC, the contract is with the GC entity, not the homeowner, and you name the project.
Several states require your license number on contracts and bid sheets. Check your state rules on our plumbing license by state page before you print anything.
2. Scope of work, in boring detail
This is the clause that saves you. Vague scope is how a “replace the water heater” job turns into re-piping a wall for free.
Bad: “Install new water heater.”
Good: “Remove and dispose of existing 40-gallon gas water heater. Furnish and install one (1) 50-gallon gas water heater, Model X. Includes new flex connectors, new gas sediment trap, new T&P discharge line to existing drain, and expansion tank. Does not include drywall repair, electrical work, gas line resizing, or permit fees beyond those listed below.”
Notice the second half. What is not included matters as much as what is.
3. Exclusions
Give this its own section and keep a standing list you reuse. Common plumbing exclusions:
- Drywall, paint, tile, flooring or landscaping repair after access is cut
- Conditions hidden behind walls, under slabs or underground
- Code upgrades triggered by inspection that were not visible at bid
- Asbestos, mold or lead abatement
- Electrical work requiring an electrician
- Existing piping outside the described work area
4. Price, and how it is calculated
Say whether it is a flat price or time and materials. If flat, list the number and what it covers. If time and materials, list your hourly rate, your after-hours rate, your material markup percentage, and your trip charge. If you are not sure your numbers hold up, run them through our free pricing calculator before you sign anything.
Sample wording: “Total contract price: $4,850. Price is based on the scope described above and is valid for 30 days from the date of this agreement. Material prices are subject to change if the work is not scheduled within 30 days.”
That last sentence matters right now. Copper moves. Locking a price for 90 days on a repipe can eat your margin, so keep an eye on the current copper price and keep your quote window short.
5. Payment terms and schedule
Get specific or get paid late. For a job over a few thousand dollars, a normal draw schedule looks like:
- Deposit at signing: 25% to 33% (check your state cap, some limit residential deposits)
- Progress payment at rough-in: 40%
- Final payment on completion and inspection sign-off: balance
Then add the teeth: “Final payment is due upon substantial completion. Balances not paid within 15 days accrue a service charge of 1.5% per month. Customer agrees to pay reasonable collection and attorney fees on past due balances, where permitted by law.”
Also say what forms of payment you take and whether you charge a card fee. Put it in writing and nobody argues at the truck.
6. Change orders
If you fix nothing else, fix this one. Change orders are where most small plumbing shops quietly lose their profit.
The clause: “Any change to the scope of work must be documented in a written change order signed by both parties before the additional work begins. Change order pricing is time and materials at $XXX per hour plus materials at cost plus XX%, unless otherwise agreed in writing.”
Then actually use it. Keep blank change orders in the van or on your phone. A two-minute signature on a $600 add is the difference between a profitable job and an argument at the end. Our free invoice and estimate generator spits out a clean, branded document you can use for change orders too.
7. Schedule and delays
Give a start window rather than a hard date, and list what pauses the clock: material lead times, permit or inspection delays, weather, customer-caused delays, and other trades not being ready. “Time is of the essence” clauses cut against you, so do not add one unless a GC insists.
8. Permits and inspections
Say who pulls the permit and who pays for it. Say that work will be performed to the code adopted in that jurisdiction. If the customer wants to skip a permit, that is your cue to walk, and your contract should say permits are required where the code requires them.
9. Warranty
Keep it clean and separate labor from parts. “Contractor warrants labor for one (1) year from the date of substantial completion. Manufacturer warranties on equipment and fixtures pass through to the Customer and are not extended by Contractor. Warranty does not cover damage from misuse, freezing, ground movement, water quality, or work performed by others.”
Water quality and freezing are the two exclusions new plumbers forget, and they are the two that come back.
10. Access, site conditions and hidden conditions
Customer provides reasonable access, water and power. You are not responsible for pre-existing conditions you could not see at bid. If you open a wall and find galvanized pipe crumbling behind it, that is a change order, not a freebie, and this clause is what lets you say so calmly.
11. Cancellation and right to rescind
Many states give residential customers a three-day right to cancel on contracts signed in the home. If yours does, the notice has to be in the contract, sometimes verbatim and sometimes in a specific type size. Look up your state requirement rather than copying a template from another state. Also add your own cancellation terms: what you keep for materials already ordered and work already performed.
12. Signatures and date
Both parties, printed name, signature, date. Get it before you order materials, not after. An e-signature is fine in almost every state, and it gets signed faster than paper.
Residential vs commercial
Residential contracts lean on consumer protection rules: deposit caps, right to cancel, required license disclosure, plain-language requirements. Keep it short and readable, one or two pages.
Commercial and GC work is the opposite. You will usually be handed their subcontract, which is written for them. Read the pay-when-paid or pay-if-paid clause, the retainage percentage, the lien waiver requirements, and the indemnification language. If you are new, the two lines worth pushing back on are pay-if-paid (you do not get paid unless the owner pays the GC, which is a risk you cannot control) and any clause making you responsible for another trade work.
Lien rights, briefly
A mechanics lien is your real leverage on unpaid work, and most states have preliminary notice deadlines measured in days from when you start. Miss the notice and you can lose lien rights on a job you already finished. Your contract should include whatever preliminary notice language your state requires. This is worth thirty minutes with a local construction attorney once, and then you have it forever.
How to actually get it signed
The best contract in the world does nothing sitting in a folder. Three things that help:
- Make it one document, not a stack. Estimate on page one, terms on page two, signature at the bottom.
- Send it the same day you quote. Momentum matters. A quote that arrives four days later loses to the guy who sent his that afternoon.
- Walk the scope out loud. Read the exclusions to the customer before they sign. It feels awkward once and prevents a fight later.
Plumbing contract FAQ
Do I need a lawyer to write my plumbing contract? You need one to review it once for your state. Start from a solid template, then pay for an hour of review. That is far cheaper than getting the deposit cap or the rescission notice wrong.
What size job needs a written contract? All of them. On a $180 service call, a signed work authorization on your phone is enough. Over roughly $1,000, use the full contract.
Can I email the contract? Yes. Electronic signatures are valid in nearly every state for this kind of agreement. Keep the signed PDF and the email trail.
What if the customer wants to change the scope mid-job? Written change order, signed, before you touch it. Every time. The one you skip is the one that costs you.
If you are still setting up the business side of things, start with how to start a plumbing business, then come back and build your paperwork stack.
