Sample invoice for plumbing work: labor plus materials, line by line

The example invoice

Every name, address, rate and price here is invented. The tax rate is an example rate: use yours. The job is a kitchen faucet swap with two new shutoff valves.

The arithmetic, step by step

1. Labor: 2.25 hours x $110.00 = $247.50.
2. Parts: $129.00 + (2 x $14.50 = $29.00) + (2 x $8.75 = $17.50) + $6.00 = $181.50.
3. Subtotal: $95.00 + $247.50 + $181.50 = $524.00.
4. Tax: $181.50 x 0.065 = $11.7975, which rounds to $11.80.
5. Total: $524.00 + $11.80 = $535.80.
6. Balance due: $535.80 - $100.00 deposit = $435.80.

In this example only the parts are taxed. Where you work, tax may apply to labor too, to nothing, or to different lines. Ask your local tax authority; the example proves nothing about your area.

Why each line is there

• Invoice number and dates: both sides can find the document later. Most invoice templates use a unique, running number.
• Job address: the place you worked, not only the billing address. Landlords, managers and offices pay for several addresses.
• Call-out fee on its own line: it covers travel and a reserved slot. Some plumbers credit it toward the repair. If you do, say so on the invoice.
• Labor with hours and rate: the client can check the sum without phoning you.
• One line per part, with quantity and unit price. A single line reading "parts $181.50" invites questions. For bigger items such as a water heater, add the make and model.
• Totals in a fixed order: subtotal, tax, deposit, balance. The eye can read straight down.
• A due date written as a date. "Net 15" alone makes the client count days.

Showing labor: hourly, flat, minimum, travel

None of this is a rule. These are common choices. Pick one, write it on your price sheet and use it every time.

• Hourly: hours x rate, as above. It suits diagnosis and jobs where the scope is unclear.
• Flat price: one agreed amount for a repeatable job. Show it as one line and list extra parts separately. Changing a flat price into hours on the invoice can start arguments.
• Minimum charge: some shops bill a minimum, for example one hour. If you do, tell the client before you start.
• Quarter-hour rounding: in the example, 2 h 10 min = 130 minutes, rounded up to 135 minutes = 2.25 h. Show the real time on the invoice so the rounding is visible.
• Travel time: either inside the call-out fee or billed as labor. Do not charge both for the same drive.

A bigger job: deposit and part payment

A water heater swap, again with invented figures and the same example tax rule (parts only). The special-order unit was paid for in part before the day, and one more payment came after day one.

1. Parts: 780.00 + 68.00 + 38.00 + 41.50 + 22.00 = 949.50.
2. Subtotal: 605.00 + 949.50 + 85.00 + 40.00 = 1,679.50.
3. Tax: 949.50 x 0.065 = 61.7175, rounds to 61.72. Total: 1,679.50 + 61.72 = 1,741.22.
4. After the deposit: 1,741.22 - 400.00 = 1,341.22. After the part payment: 1,341.22 - 600.00 = 741.22.

The deposit here is about 23% of the total ($400.00 / $1,741.22). That share is your choice. Rules on deposits can differ by place, so check yours before you set one. Show each payment with its date, so the client sees what is paid and what is still owed.

Materials: cost, price and markup

Your cost is what the supplier charged you. The price is what you put on the invoice. The client sees the price, not your cost. How much to add is the owner's decision.

Example: a part costs you $64.00. Here is what different markups on cost do:

Markup and margin are not the same number. A 30% markup leaves 23.1% of the price, because the extra is measured against cost, not against price. That money also has to pay for the trip to the supplier, storage and parts that fail.

Keep every supplier receipt and match it to the job. It helps to prove what you paid and to answer a client who asks about a price.

Why clients pay late, and a 10-point checklist

Invoicing guides often name causes such as vague line items, missing payment terms, invoices sent late and no follow-up. Two more causes are common in the trade: no job address, and no purchase order number when the client is a business, because many offices cannot pay a bill they cannot match to an order.

1. A unique invoice number, in order.
2. Your business name, phone and, where your area requires it, your license number.
3. The client's name and the job address.
4. The date of the work and the invoice date.
5. A PO or reference number if the client is a business that uses them.
6. One line per part, with quantity and unit price.
7. Labor shown as hours x rate, or as one agreed price, and which one it is.
8. Subtotal, then a tax line with its name and rate, then deposits, then balance due.
9. A due date and the ways to pay.
10. Sent within a day or two of the job, with a copy kept.

Numbering and keeping copies

General practice: one running number, never reused. If you issued one by mistake, mark it void and issue a new one. Do not edit a sent invoice.

What the law requires varies. As examples from two countries: the US tax agency says to keep records as long as needed to prove income or deductions on a return. Spain's tax agency says an invoice carries a number and, where applicable, a series, with consecutive numbering within each series. Neither page is advice for your case. Ask your local tax authority or accountant.

Whatever tool you use, re-add the totals once by hand before you send.

Questions

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About Wrenvik

Wrenvik is our Windows app for making estimates and invoices for your trade and saving them as PDF. Your clients and prices are stored on your PC. It helps you write documents and does not give tax or legal advice. It is not in the Microsoft Store yet.

Sources

• BuildOps: plumbing invoice example
• Housecall Pro: plumbing invoice template and examples
• Joist: invoicing and estimating guide for plumbing contractors
• Simplywise: how to write a plumbing invoice
• IRS: recordkeeping (United States, one example)
• Agencia Tributaria: contenido de las facturas (Spain, one example)

Checked 2026-11-03.