What should be included on a plumbing invoice?

Every plumbing invoice needs your business name and state license number, the customer's name and service address, a unique invoice number, itemized labor and materials with unit prices and quantities, sales tax broken out separately, the total amount due, payment terms with a calendar due date, and accepted payment methods. For commercial jobs, add the PO number. Missing any of these slows payment and can weaken your lien rights in states that require license numbers on invoices.

How soon should I send a plumbing invoice after completing work?

Send it the same day, ideally before you leave the job site. Contractors who invoice within 24 hours of job completion get paid 10-14 days faster on average than those who batch invoices weekly, based on contractor payment surveys. For residential service calls, email a PDF from the truck. For milestone-based commercial work, send the invoice the morning after the milestone is verified. Every day of delay adds roughly one day to your collection timeline.

What payment terms should a plumber use on invoices?

Residential service work should be due-on-receipt or Net 15. Commercial and new-construction plumbing typically runs Net 30. Always state the due date as a specific calendar date, not just the term. Add a late-payment penalty of 1.5% per month, and consider offering a 2% early-payment discount for payment within 10 days. The median DSO for plumbing contractors is 43 days according to CFMA, so tighter terms and clear due dates help you collect faster.

What is a good markup on plumbing materials?

Most plumbing contractors target a 30-50% gross margin on materials, which translates to a markup of roughly 43-100% on cost, depending on the item and job type. Commodity fittings and pipe can carry a lower markup; specialty fixtures and equipment warrant more. According to PHCC benchmarks, if your material margin is consistently below 25%, you are undercharging. Track your actual supplier cost against what you invoice on every job to make sure your margin holds.

Do plumbers need to charge sales tax on invoices?

In most U.S. states, materials installed by a plumber are subject to sales tax. Labor is exempt in many states but not all. The rules vary significantly: Texas taxes labor and materials together on lump-sum contracts, while California generally taxes only the materials portion. Check your state revenue department's guidelines for construction contractors annually. On your invoice, always separate taxable materials from non-taxable labor to keep your liability clear and avoid audit issues.

How to Write a Plumbing Invoice That Gets Paid Fast

The Six Required Elements of a Plumbing Invoice

Every plumbing invoice needs these six components or you risk delayed payment, disputes, or both:

Your business information: Company name, address, phone, email, and state plumbing license number. Many states (Texas, California, Florida among them) require the license number on any customer-facing document. Omitting it can void your lien rights in some jurisdictions.
Customer and job details: Customer name, billing address, and the service address if different. For commercial work, include the PO number if one was issued.
Unique invoice number: Sequential numbering (INV-2024-0415, for example) prevents duplicates and makes reconciliation in QuickBooks straightforward.
Itemized line items: Every part, fixture, and labor block on its own line with quantity, unit price, and extended price.
Tax and totals: Sales tax (materials are taxable in most states; labor treatment varies), subtotal, and the amount due.
Payment terms and methods: Net 15, Net 30, or due-on-receipt, plus every payment method you accept. More on selecting the right terms below.

Miss any of these and you give the customer a reason to sit on the invoice. According to a 2023 Billd/CFMA survey, 49% of contractors report that invoice disputes are the top cause of slow payment. Most disputes trace back to missing details or vague line items, not actual disagreements about the work.

How to Itemize Labor and Materials

Lump-sum invoices invite questions. Itemized invoices close them. Here is how to break down a typical residential service call:

Labor

List each technician's time separately. Use quarter-hour increments. Show the hourly rate and the total. Example:

Journeyman plumber, 2.5 hrs @ $125/hr = $312.50
Apprentice, 2.5 hrs @ $65/hr = $162.50

If you charge a trip or diagnostic fee, put it on its own line. Burying it inside labor hours creates confusion and looks like you are padding the bill.

Materials

List every part with a description specific enough for the customer to understand, but not so granular that it becomes noise. Include the manufacturer or spec when the part is significant:

3/4" PEX-A tubing, Uponor, 25 ft @ $1.85/ft = $46.25
SharkBite 3/4" push-fit coupling, qty 4 @ $8.50 = $34.00
A.O. Smith 50-gal gas water heater, Model GCV-50, qty 1 = $1,285.00

A common mistake: marking up materials without knowing your actual cost. If your material markup is less than 25-35%, you are likely leaving money on the table. According to PHCC benchmarks, the average plumbing contractor targets a 30-50% gross margin on materials depending on the job type. If you are not tracking this per invoice, read why contractors lose money on jobs for a breakdown of where profit leaks happen.

Permits and Fees

If you pulled a permit, pass that cost through as its own line item. Same for disposal fees, rental equipment, or inspection coordination. These are real costs and burying them inside your labor rate shrinks your margin without the customer even knowing the expense exists.

Setting Payment Terms That Actually Work

The most common payment terms in residential plumbing are due-on-receipt or Net 15. Commercial and new-construction work typically runs Net 30. According to the 2023 CFMA Financial Benchmarker, the median days sales outstanding (DSO) for plumbing contractors is 43 days. That means even at Net 30, most plumbing shops wait nearly six weeks to collect.

Three ways to tighten that number:

State the due date as a calendar date, not just "Net 30." "Due by July 15, 2025" removes any ambiguity about when the clock started.
Add a late-payment penalty. 1.5% per month (18% annually) is standard and legal in most states. Put the penalty clause on the invoice itself, not just buried in your contract.
Offer a small early-payment discount. 2/10 Net 30 (2% off if paid within 10 days) costs you less than carrying receivables for six weeks.

For a deeper dive into structuring terms that protect your cash flow, see contract invoice payment terms for trade contractors.

Sending the Invoice: Timing and Delivery

Send the invoice the same day you finish the work. Every day you delay costs you roughly one additional day of DSO on the back end. Contractors who invoice within 24 hours of completion get paid an average of 10-14 days faster than those who batch invoices weekly, according to data from payment platform Joist's 2022 contractor survey.

For residential service work, hand the customer a PDF on-site or email it before you leave the driveway. For larger jobs billed on progress milestones, send the invoice the morning after the milestone is verified. The fewer hours between "work done" and "invoice received," the fewer excuses exist for delay.

If you use QuickBooks, you can build and send invoices from the field without waiting to get back to the office. Details on making that workflow practical are in using QuickBooks on a job site.

Digital vs. Paper

Email with a PDF attachment is the standard for residential. Commercial GCs often require invoices submitted through a portal (Textura, GCPay, Procore). Whatever the method, always keep a timestamped record of when the invoice was sent. That timestamp is your leverage if payment terms are disputed later.

Common Plumbing Invoice Mistakes That Cost You Money

After reviewing thousands of contractor invoices, the same errors surface repeatedly:

No license number. In states like California (CSLB requirement) and Texas (TSBPE requirement), omitting your license number can weaken or void your mechanic's lien rights. It also signals to commercial customers that your paperwork is sloppy, which makes them scrutinize everything else.
Vague line items. "Plumbing repair" or "miscellaneous materials" tells the customer nothing. If they cannot verify what they are paying for, they will call you instead of writing a check. Every call is a 5-15 minute delay and a chance for the invoice to fall to the bottom of the pile.
Missing PO numbers on commercial work. GCs and facility managers process hundreds of invoices a month. No PO number means your invoice gets kicked back and you restart the payment cycle from zero.
Not separating taxable and non-taxable items. In many states, labor is exempt from sales tax but materials are not. Combining them into a single total makes your tax liability unclear and can trigger audit issues. The BLS and individual state revenue departments publish taxability rules; check yours annually.
Rounding material costs instead of tracking actuals. A $5 rounding error on fittings is trivial. But across 200 invoices a year, those rounding errors add up to $1,000 or more of margin you cannot account for. Plumbing contractors running 8-12% net margins (which is the realistic range for most shops, per IBISWorld's 2024 industry report on plumbing services, NAICS 23822) cannot afford that slippage.

[ADD FIRST-HAND DETAIL: A specific example of how correcting one of these invoice errors changed your collection speed or margin on real jobs, with dollar amounts.]

Plumbing Invoice Template Breakdown

Here is the structure laid out section by section. You can replicate this in any invoicing tool or build it once in QuickBooks as a custom template:

Header

Company logo and name
Address, phone, email
State plumbing license number
Invoice number and date

Customer Block

Customer/company name
Billing address
Service address (if different)
PO number (commercial jobs)

Line Item Table

Description column (specific enough to stand alone)
Quantity
Unit price
Extended price
Separate sections or subtotals for labor, materials, permits/fees

Totals Block

Subtotal
Sales tax (itemized by rate if multiple rates apply)
Total due
Amount already paid (deposits, progress payments)
Balance due (bold, large font)

Footer

Payment terms with calendar due date
Late-payment penalty language
Accepted payment methods (check, ACH, credit card, Venmo, etc.)
Brief warranty or guarantee statement if applicable

This structure works for a $350 garbage disposal swap or a $45,000 commercial repipe. Scale the detail level to the job size, but never cut the required elements.

Track Profit Per Invoice, Not Just Revenue

An invoice tells you what you billed. It does not tell you what you earned. If you are not comparing each invoice against your actual labor cost (burden rate, not just hourly wage) and actual material cost (what you paid the supplier, not list price), you are flying blind on margin.

The average plumbing contractor operates on a net profit margin between 8% and 12%, according to IBISWorld's 2024 report on U.S. plumbing services. At those margins, a 5% cost overrun on materials wipes out nearly half your profit on a job. The invoice is the last place you can catch that overrun before the money is gone.

Build a habit: before you send every invoice, compare the total against your estimated job cost. If the margin is below your target, figure out why before you move on. That five-minute check is worth more than any marketing campaign you will ever run.

If you want to stop guessing at your margins, try Fieldpaid free for 7 days. No credit card required. It pulls prices straight from your QuickBooks item list and tracks real job profit automatically, so you know what every plumbing invoice actually earned you before you send it.