Plumber invoicing: how to invoice as a plumber in the UK

Invoicing is the part of plumbing nobody trained you for, but it's the part that decides whether you actually get paid for the work you've done. This covers exactly what a plumber's invoice needs, how to handle VAT and deposits, and how to get the bill out before you've left the job so you're not chasing it next week.

TL;DR

• A plumber's invoice needs your details, the customer's details, a unique invoice number, the date, a clear breakdown of labour and parts, the amount due, and how to pay.
• If you're VAT registered, add your VAT number and show VAT per line; if you're not, set lines to no VAT and say so.
• Split labour and materials on the invoice — it's clearer for the customer and matters if CIS ever applies to your work.
• Send it the day the job finishes (ideally from the job), take deposits on bigger work, and put your bank details and a payment reference on every invoice.
• Doing it on your phone on-site is the single biggest thing that gets plumbers paid faster.

What a plumber's invoice must include

Whether it's a tap washer or a full bathroom, the invoice needs the same bones:

• Your business details — name and address, contact, and your VAT number if registered. Limited company? Include the registered name and company number.
• The customer's details — name and address.
• A unique invoice number and the date (see our guide on invoice numbering).
• A description of the work — broken into labour and parts so the customer can see what they're paying for.
• The amounts — line prices, any VAT, and the total due.
• Payment terms and how to pay — due date, bank details or a payment link, and a reference (use the invoice number).

Labour, materials and parts — split them out

Plumbing invoices are nearly always labour plus parts, so list them separately: e.g. "Replace mixer tap — labour £90" and "Bristan mixer tap — £65". It heads off the most common dispute (the customer thinking the parts were included in your hourly rate), and it keeps your records clean if you ever work under the Construction Industry Scheme, where only the labour portion is subject to CIS deductions, never the materials.

Pro Tip: Keep a saved list of your common jobs and parts with prices, so building an invoice is picking from a list rather than typing it out each time.

VAT for plumbers

If your turnover is below the VAT registration threshold you don't have to charge VAT — set every line to no VAT and mark the invoice "Not VAT registered" so customers aren't confused. If you are registered, charge the correct rate per line (most plumbing labour and standard materials are 20%, though some work on new-build or certain energy-saving installations can be reduced-rated — check the specific job), show your VAT number, and give the totals excluding and including VAT. If you do construction work as a subcontractor for a VAT-registered contractor, the domestic reverse charge may apply, which changes who accounts for the VAT — worth checking before you invoice that kind of job.

Deposits and staged payments

For anything beyond a small call-out, take a deposit up front — it covers your materials and signals a serious customer. On a bathroom or a big job, invoice in stages (deposit, first fix, completion) rather than carrying the whole cost until the end. Each stage is its own numbered invoice, referencing the same job, so the paper trail stays clean and your cash flow doesn't take the hit.

Get paid faster: send it from the job

The gap between finishing and invoicing is where plumbers lose money — the invoice that "can wait until the weekend" slips to next month. The fix is to raise and send it before you leave:

• Invoice on your phone the moment the job's signed off.
• Put bank details and a payment reference (the invoice number) right on the invoice.
• Send by WhatsApp or email — most customers open WhatsApp faster.
• Set one polite automated reminder for a few days after the due date instead of chasing by hand.

Make it one tap

A mobile invoicing tool turns this from an evening admin job into two minutes on-site. VanBill is built for UK trades: pick the customer, add labour and parts (VAT and CIS handled), and send a branded PDF by WhatsApp or email before you're back in the van — with reminders that chase for you. You can start free.

FAQ

Do plumbers have to charge VAT?

Only if you're VAT registered (required once your turnover passes the threshold). Below that it's optional; if you're not registered, don't add VAT and mark the invoice "Not VAT registered".

Should a plumbing invoice separate labour and parts?

Yes — it's clearer for the customer, reduces disputes, and matters for CIS, where only labour is subject to the deduction, not materials.

Can I invoice from my phone as a plumber?

Yes, and you should. A mobile invoicing app lets you send a compliant invoice from the job in minutes, which is the most reliable way to get paid sooner.

Should I take a deposit?

For anything beyond a small call-out, yes — it covers your materials and confirms the customer is serious. On big jobs, invoice in stages.