CIS registration and monthly handling
We register you for gross payment status where you qualify (so contractors pay you in full without the 20% deduction), file or reconcile CIS, and chase missing deduction statements that hold up your refund.
Who we helpIndustry guide
Plumbers accounting, handled.
Drowning in Paperwork While Your Tools Gather Dust?
Looking for an accountant for plumbers who actually understands CIS deductions, the VAT reverse charge and the zero rate on heat pumps? Zmartly are ACCA-qualified plumbers' accountants who handle the Construction Industry Scheme, your van and tools, and Self Assessment so you keep more of what you bill. You get a named accountant, fixed monthly pricing and replies within 72 hours, all in plain English, not jargon.
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Plumbers · 2026/27
CIS deductions and key rates for plumbers
If you take on or work as a subcontractor in construction, the Construction Industry Scheme (CIS) sets how much tax a contractor must deduct from your labour payments before you are paid.
- VAT domestic reverse charge for construction since 1 March 2021
- Mileage 55p per mile for the first 10,000 miles (25p thereafter)
- Annual Investment Allowance £1,000,000 on plant and tools
- VAT registration threshold £90,000 turnover
| Status | CIS deduction | What it means |
|---|---|---|
| Registered subcontractor | 20% | Standard rate deducted from labour once you are verified and registered for CIS |
| Unregistered subcontractor | 30% | Higher rate applied until you register with HMRC for CIS, so register early |
| Gross payment status | 0% | Paid in full with no deduction; you settle the tax via Self Assessment instead |
Heads up, Gross payment status requires passing a turnover test of £30,000 net per partner or director (or £100,000 for the whole entity) plus compliance and business tests, so check you qualify before applying.
Tailored services
Everything you need for plumbers.
01 02 VAT registration and reverse charge setup
We watch your turnover against the £90,000 VAT registration threshold, advise whether the Flat Rate Scheme or standard VAT suits a plumbing business, and configure the domestic reverse charge correctly in your software.
03 Energy-saving and heat pump VAT advice
Installing heat pumps, solar thermal or insulation? Many of these qualify for the 0% VAT rate until 31 March 2027 (5% reduced rate after). We make sure you apply the right rate so you neither overcharge customers nor underpay HMRC.
04 Self Assessment and limited company accounts
Whether you are a sole trader or run a limited company, we prepare and file your return, claim every allowable expense, and tell you what to set aside, well before the 31 January deadline.
05 Capital allowances on van, tools and equipment
We claim the Annual Investment Allowance (up to £1 million) on qualifying plant and tools, treat your van correctly for tax, and keep a clean asset register so nothing claimable slips through.
06 Bookkeeping on software you already use
We work in Xero, QuickBooks, FreeAgent or Sage, link your bank, and turn van-floor receipts and invoices into tidy records so your figures are right and your tax is never a shock.
How we work
Four steps from first call to filed.
01 Discovery
Understanding your business needs.
02 Solution Design
Crafting your custom accounting strategy.
03 Onboarding
Quick and easy integration.
04 Regular Rhythm
Consistent monitoring and reporting.
Guides for plumbers
Plain-English explainers, kept current with the latest HMRC rules.
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Common questions
Frequently asked questions.
If you do construction work for a contractor, they must deduct money from your labour and pay it to HMRC as advance tax. Registered subcontractors have 20% deducted; if you have not registered for CIS it is 30%. Deductions are taken from labour, not from materials you have paid for, provided you have evidence. We reconcile these against your tax bill so you are not taxed twice and any overpayment is refunded.
Yes, if you qualify for gross payment status. To get it HMRC look at your turnover, your tax compliance history and whether your business is run through a bank account in the UK. With gross status contractors pay you in full and you settle your own tax later. We assess whether you qualify and apply on your behalf.
Only once your taxable turnover passes the £90,000 registration threshold over a rolling 12 months (or you can register voluntarily). Once registered, if you work for another VAT-registered contractor the domestic reverse charge usually applies, meaning you do not add VAT to labour, the customer accounts for it instead. For work for a private homeowner end user, you charge VAT as normal.
For now, yes, on qualifying installations. The installation of certain energy-saving materials, including air and ground source heat pumps, solar panels and insulation, is zero-rated for VAT until 31 March 2027, after which it is due to revert to the 5% reduced rate. Getting the rate right matters, so we check each job against the qualifying list.
Yes. Tools, test equipment and most plant can be claimed under the Annual Investment Allowance, which lets you deduct the full cost (up to £1 million a year) in the year you buy. A van bought for the business can also be written off in full under the AIA, which is different from how a car is treated. We make sure your van is claimed correctly.
If you use simplified mileage, you can claim 55p per business mile for the first 10,000 miles in the year and 25p after that, covering fuel, insurance, servicing and repairs. Tolls and parking on a business journey are claimable on top. Travel from home to a regular workplace does not count, so we keep a proper business mileage record to back the claim.
Yes. If you work 25 hours or more a month from home you can use HMRC's flat-rate home-working allowance, or we can calculate an actual proportion of your household costs if that gives a better result. For most plumbers running the books and quotes from a home office, this is a small but worthwhile claim we set up once and apply every year.
Free · 30 minutes · No obligation
Stop overpaying tax. Start filing in 5 days.
Thirty minutes with an ACCA-qualified accountant. Most owners uncover £1,000-£3,000 in annual savings on the first call. If we are not the right fit, you walk away with a free tax review on the house.
