Plumber invoice template UK (2026): CIS, VAT, and a worked example

The short answer

A UK plumber invoice depends on who you bill, not just what job you did. A homeowner gets a normal invoice with VAT only if you are registered (threshold £90,000). A VAT-registered contractor gets labour and materials split, your UTR, and CIS at 20% or 30% on the labour. If both of you are VAT-registered and reverse charge applies, show the VAT but do not add it to the amount they pay.

Homeowner or contractor: which invoice should you send?

Most "plumber invoice template UK" pages treat every customer as a name, an address and a total. On the van they are not. The customer type decides whether CIS, reverse charge or plain VAT sits on the bill, and it decides how they want to pay.

• A homeowner or landlord gets a standard invoice, with VAT at the right rate if you are registered. They cannot reclaim it.
• A VAT-registered contractor paying you for construction operations gets labour and materials split, your UTR, and a CIS deduction of 20% (verified) or 30% (unverified).
• If you and the contractor are both VAT-registered and the work is reported under CIS, domestic reverse charge applies, so they account for the VAT on their own return.

A contractor working for a homeowner is still a contractor. There is no reverse charge on a supply to a private customer, because that customer is not VAT-registered. The old shortcut "it is a house, so they are an end user" is wrong. If you invoice the contractor, reverse charge can still apply.

What must be on a UK plumber invoice?

GOV.UK is narrower than most blogs. You must give an invoice by law when both you and the customer are VAT-registered, and it must say how much they pay and when. If you are not VAT-registered, HMRC still expects you to keep records of what you charged, and a numbered invoice is how you get paid. The registration threshold is £90,000 of taxable turnover in a rolling 12 months, so register for VAT if you have gone over it or will.

The baseline list from GOV.UK: a unique invoice number, your name and address (or company name, number and registered office), the customer's name and address, a clear description, the supply date, the invoice date, the amount being charged, the VAT amount if applicable, and the total owed. A Gas Safe registration number can sit in the header if you have one, but it is not a legal invoice field and it is not something InvoiceAdept issues.

Clear description is the line that actually gets you paid.

Weak	Usable
Plumbing works	Replace 30kW combi and first-fix new bathroom (soil, wastes, hot and cold), 22 Maple Close, 28 August 2026
Call-out	Call-out, burst 15mm under kitchen sink, 22 Maple Close, 28 August 2026, includes first 45 minutes
First fix	First-fix bathrooms, plots 4 to 7, week ending 28 August 2026, 4 plots
Gas cert	Landlord gas safety check, 22 Maple Close, appliance list on CP12 GS-2026-0142, issued 28 August 2026

How do labour and materials split on plumbing work?

On a homeowner invoice the split is courtesy, so they can see what the boiler cost. On a contractor invoice the split is the CIS calculation. HMRC starts with the gross invoice, then takes off VAT, consumable stores, fuel used (not travelling), plant hired for that job, and materials you paid for directly. What is left is the CIS base, and the contractor applies 20%, 30% or 0% to it.

Materials means what you actually paid for this job: the combi, the flue kit, the cylinder, sanitaryware, copper, plastic waste, isolation valves and the TRVs you bought. A mark-up on the boiler is not a material for CIS, so it sits in the labour base. Pipe the main contractor issued from their own stores is not your material either, because you did not pay for it.

Two habits cost money. One line such as "boiler replacement £1,820" lets a cautious contractor deduct 20% of the entire lump, so you are light on the appliance until Self Assessment. Stuffing the mark-up into "materials" so CIS looks smaller rarely survives a request for receipts, and an estimate is rarely in your favour.

How does CIS work for a plumber at 20% or 30%?

You get 20% if you are registered and they can verify you, 30% if you are not registered, they cannot verify you, or you gave the wrong business name, and 0% if HMRC has granted gross payment status. Give them the legal name and UTR you registered with, because a trading name that does not match is how you land the 30% rate.

Bathroom first-fix, a new heating system, a new soil stack on a site, and sanitation and water-supply installation for a contractor are construction operations, so CIS applies. But HMRC's guidance treats many isolated repairs to an existing system as outside CIS, such as soldering a leaking pipe or replacing a tap. If one contract mixes an excluded repair with in-scope construction, HMRC treats the lot as in, so do not invent a split invoice to dodge it.

Show on the PDF: your UTR, labour, materials, the CIS rate, the deduction in pounds, and the net payable. That printout is not a CIS300, so InvoiceAdept still does not file the return to HMRC.

When does domestic reverse charge apply to a plumber?

Reverse charge applies when you supply specified building and construction services, both you and the customer are VAT-registered, the work is reported within CIS, the supply is standard- or reduced-rated, and the customer has not given a written end-user notice. Installing heating, water, drainage and sanitation systems is on HMRC's list. Many new-build housing labour supplies are zero-rated, so reverse charge does not apply to those.

You still show everything a VAT invoice needs, but you use the words reverse charge, state the VAT they must account for, and do not add it to the amount they pay. On a supply-and-fix, goods supplied with the construction service are one supply, so reverse charge sits on the full net value. CIS is the opposite, so keep the lines split so both calculations stay visible.

Reverse charge never applies to a private householder, so do not put that wording on a domestic leak bill.

When does Making Tax Digital for Income Tax start, and what is the VAT threshold?

Making Tax Digital for Income Tax arrives 6 April 2026 for self-employed sole traders and landlords with income over £50,000, then £30,000 from April 2027 and £20,000 from April 2028. You keep digital records and send quarterly updates rather than one annual return. The VAT registration threshold sits separately at £90,000 of taxable turnover in a rolling 12 months.

If you are not VAT-registered, leave VAT off the invoice. Do not invent a "VAT: N/A" line. If you are registered, you carry the VAT number, rate, net and VAT in sterling on a full VAT invoice. Check the full guidance at Use Making Tax Digital for Income Tax before you rely on a date or a rate.

Can I claim mileage, and how should deposits be invoiced?

HMRC's approved mileage rates are 45p per mile for the first 10,000 business miles a year and 25p per mile thereafter, which is the figure for a car or van. Plumbers often claim both the travel and the time, so keep the two separate in your own records. The mileage allowance is not a customer invoice line; it is your expense claim.

A deposit is a tax point for VAT when you receive it, so invoice it and number it. A typical pattern on a domestic bathroom or boiler is a deposit of 30 to 50% before you order the appliance, a stage invoice when first-fix is signed off, then a final invoice for the balance less the deposit, plus any extras approved in the chat. Write the percentages in the quote, not in a voice note. Retention is not a deposit, so the final invoice still shows the full value, the amount withheld, and the date it becomes due.

How does InvoiceAdept fit a plumber's invoices?

InvoiceAdept raises the invoice, stores the record and, on Pro+, prints the CIS lines. It does not file a CIS300 or submit Making Tax Digital updates to HMRC. If the job was sold in WhatsApp, put the invoice in that thread with the number, due date and a pay link; native WhatsApp send is on Pro. A main contractor is the opposite, so email the PDF to accounts with the purchase order in the reference.

Learn more: invoicing features for the generally-applicable walkthrough and the CIS invoicing breakdown. Compare plans on pricing and find your trade in the plumbers trade directory.

FAQs

What should a UK plumber invoice include?

Your legal name and address, the customer's name and address, a unique invoice number, the invoice date, the supply date if different, a description that identifies the work (address, what changed, which appliance or bathroom, and which certificate if you issued one), quantities and rates, a due date, and a way to pay. Split labour and materials, and add VAT only if you are registered and reverse charge does not apply.

Do plumbers need a CIS invoice?

Only when a contractor is paying you for construction operations, such as installing heating, water, drainage or sanitation systems. A homeowner leak, a private combi you sold yourself, or a landlord gas safety check is a standard invoice with no CIS. Many isolated repairs to existing systems sit outside CIS too, though a mixed contract can pull the lot back in.

How do CIS deductions work on a plumber's labour and materials?

CIS is on labour only. The boiler, flue and sanitaryware you paid for come off the gross before the rate is applied, if the contractor is satisfied you paid for them, and receipts help. The rate is 20% if you are verified, 30% if you are not, and 0% if HMRC has granted gross payment status. A mark-up is not a material.

Do I charge VAT on a domestic plumber invoice?

If you are VAT-registered and the customer is a private householder, yes, at the rate VAT Notice 708 gives for that work. Most work to an existing dwelling is standard-rated, qualifying new builds can be zero-rated, and some energy-saving heating installations have a different rate under Notice 708/6. If you are not registered, do not charge VAT.

When does domestic reverse charge apply to a plumber?

When you and the customer are both VAT-registered, the work is reported under CIS, the supply is standard- or reduced-rated, and they have not given a written end-user notice. Then you show the VAT but do not add it to the total. It never applies to a private householder.

Should I put my Gas Safe number on the invoice?

If you are on the Register and the job involved gas, yes, because landlords and agents look for it. It is a description, not a legal invoice field. Do not print a number you are not on, and do not stamp Gas Safe on a cold-water leak. InvoiceAdept does not issue Gas Safe registration and does not generate a CP12.

The bottom line

Decide who you are billing before you type a line, then split labour and materials and describe the work so a stranger can identify it. A homeowner gets a normal invoice with VAT only if you are registered. A VAT-registered contractor gets CIS at 20% or 30% on the labour, and reverse charge wording when it applies. Start free and raise your first plumber invoice in 30 seconds.