How to invoice as a plumber (UK)

How plumbers normally break the money down

A plumber's invoice is usually a call-out charge that covers the first hour, hourly labour after that, and parts at cost or with a stated markup. Keeping those apart is what stops the customer asking what the total covered.

Step by step

1. 1Write down the job address and what the fault actually was before you leave — "no hot water, faulty diverter valve" beats "boiler job" three weeks later when the customer queries the bill.
2. 2Put the call-out charge on its own line and say what it includes. Most disputes are about a customer thinking the first hour was free.
3. 3Add labour beyond the call-out as hours × your hourly rate, not as a lump sum. Two hours at £45 reads as fair; £90 of "labour" reads as a guess.
4. 4List parts individually — valves, fittings, pipe, a new pump — with the price you're charging. If you mark parts up, say so once in your terms rather than hiding it.
5. 5Add your Gas Safe or WaterSafe registration number and any parts guarantee, then send it the same day while the customer still remembers you standing in their kitchen.

When to send it

Same day for domestic call-outs and repairs. For a bathroom or full system install, invoice on completion, or in stages if the job runs over a week.

Domestic plumbing invoices are usually settled within a fortnight. If nothing lands by day 14, a short text with the invoice number and total works better than another email.

Common questions

Should a plumber charge a call-out fee on the invoice?

Yes — show it as its own line and state what it covers. A call-out that quietly includes the first hour of labour is the single most common cause of a queried plumbing invoice.

Do I have to itemise parts on a plumbing invoice?

There is no legal requirement to break parts down individually, but it is far easier to defend a bill that lists a pump, a valve and pipe than one that says "materials".

What should a plumber's payment terms be?

14 days is the norm for domestic work and 30 days for letting agents or commercial customers. Whatever you pick, put it in writing on the invoice — otherwise the statutory default of 30 days applies.