Invoicing is treated as office work that happens after the job. The invoices that get paid quickly are mostly decided on site, in the two minutes before the plumber leaves.
Step 1. Record it before you leave
Everything the invoice needs should be captured while you are standing in front of the work.
- What the problem was, in the customer's words and in yours
- What you did about it
- Parts used, including the small ones
- Time on site, and travel if you bill it
- Anything you found and did not do, which is a future job
- Photos of the finished work
Parts are where invoices leak. Two ball valves, a pack of washers and a tube of sealant is thirty or forty dollars that never reaches the invoice, on every job, forever.
Step 2. Tell them the number before you go
This is the step that prevents most disputes, and it is the one most often skipped because it is uncomfortable.
If the work was quoted, confirm it is the quoted figure. If it ran over, say so now and say why, while they can see the work. A customer who hears "it came to $480, which is the $420 we agreed plus the shut-off valve we had to replace" understands. The same customer receiving that invoice three days later feels ambushed.
Rule: nobody should ever first learn what a job cost by opening an email.
Step 3. Raise it the same day
The invoice should exist before the plumber gets home. Every day of delay costs you on both ends: the payment clock starts later, and the details get fuzzier.
Where possible, raise and send it on site. A customer who receives the invoice while you are packing the van pays noticeably faster than one who receives it on Thursday.
Step 4. Get the content right
Covered in full in what a plumbing invoice should include, but the short version: who you are with your licence number, who is being billed and at what property, an invoice number, the dates, what you did in plain language, the amount, tax handled correctly, how to pay, and by when.
The free invoice generator lays all of this out if you do not have a template.
Step 5. Send it where they will see it
Email for the document, text for the notice. A text saying the invoice has been sent, with the amount, costs nothing and dramatically reduces "I never received it".
Step 6. Make paying easy
Every extra step between reading the invoice and paying it loses some proportion of customers to another day. A payment link is worth more than a discount for early payment, and costs less.
Step 7. Chase on a schedule, not on a feeling
Decide the schedule once so nobody has to decide each time whether it is too soon.
| When | What | Tone |
|---|---|---|
| Day 1 | Text confirming it was sent | Informational |
| Day 7 | Polite reminder, invoice attached again | Assume it was missed |
| Day 14 | Phone call | Friendly, ask if there is a problem |
| Day 30 | Formal notice of terms | Businesslike |
| Day 60 | Decision: collections, small claims, or write off | Decided, not drifted into |
More on this in following up unpaid invoices.
Step 8. Check the job actually made money
The invoice tells you what you charged. It does not tell you what you made. Compare what went out against what came in on a sample of jobs each month using the service call profit calculator.
The jobs that lose money are rarely the ones you expect. They are usually the short ones with a long drive.
The mistakes that cost the most
Batching invoices weekly. Every job waits an average of half a week before the payment clock even starts.
Vague descriptions. "Plumbing work, $480" invites a question. "Diagnose and repair leaking supply under kitchen sink, replace isolation valve and flex connectors" does not.
Not invoicing small jobs promptly. A $95 call-out is easy to leave. Twenty of them is $1,900 sitting in a notebook.
No terms on the document. If the invoice does not say when payment is due, it is due whenever the customer decides.
General guidance. Tax treatment, licence display requirements and what makes an invoice legally enforceable vary by state.
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