Making Tax Digital for Plumbers —
Call-Outs, Parts & Boiler Installs Explained
Emergency Call-Outs Price Differently — They Still Count the Same
Few trades see pricing swing as dramatically as plumbing — a routine tap replacement might be £80, while a burst pipe at 11pm on a Sunday can be £250 or more. However your pricing structure works, every payment you receive counts identically towards your MTD qualifying income. There's no special category for emergency, weekend, or out-of-hours premiums; they're simply part of your total self-employment income for the year.
Parts and Labour, Boiler Installs, and CIS Work
Whether you're fitting a replacement part on a call-out or supplying and installing a full boiler, your qualifying income is the full invoice total, parts and labour combined, before deducting what you paid your supplier or merchant. What you spent on parts and materials is claimed back separately as a business expense, reducing your taxable profit but not your gross qualifying income.
Plumbers who also work as CIS subcontractors on larger construction or renovation projects follow the same gross-income rule as any CIS trade: your qualifying income is based on your invoiced amount before the contractor's CIS deduction, not your net take-home after tax is deducted at source.
Records for Call-Outs, Installs and Parts
Plumbers move between emergency call-outs, boiler and bathroom installs and parts bought on trade accounts. A job log with parts linked keeps the margin visible.
- Log call-outs with date, address, fee and payment method.
- Record bathroom and boiler installs with deposits on receipt.
- Keep merchant account statements and parts receipts matched to jobs.
- Keep Gas Safe and trade body costs where they apply.
- Keep van, tool and insurance costs separately.
Where Plumbers Slip Up on MTD
- Testing on profit. Parts do not reduce the income used for the threshold.
- Forgetting out-of-hours premiums. They are income like any other.
- Losing cash. Cash customers count, and cash call-outs are easy to miss.
- Treating tools as one-offs. Larger kit is a capital allowance.
- Skipping CIS. If you work for contractors, record the gross invoice.
A Sample Quarter: What the Update Looks Like
A sample quarter for a plumber with a mix of install work and emergencies.
| Q2: 6 July to 5 October 2026 | Amount |
|---|---|
| Installs and replacements | £12,800 |
| Emergency call-outs | £5,400 |
| Landlord and agency work | £3,900 |
| Total income | £22,100 |
| Parts and materials | £6,800 |
| Van, fuel and insurance | £2,350 |
| Tools and trade costs | £720 |
| Phone and software | £330 |
| Total expenses | £10,200 |
| Profit for the quarter | £11,900 |
Out-of-hours premiums count as income, and parts are expenses.
Worked Example
Reactive call-outs and repairs (gross, including parts): £24,600
Boiler installations (gross, including parts): £16,800
CIS subcontract labour (gross, before 20% deduction): £8,200
Total qualifying income: £49,600 — just under the £50,000 Phase 1 threshold, above £30,000. Harvey joins MTD from April 2027, but given how close he sits to £50,000, one more boiler install season could tip him into the earlier Phase 1 date, so tracking through the year matters.
What You Can Claim
- Parts and materials — boilers, pipework, fittings, valves
- Gas Safe registration and annual renewal fees
- Van costs — fuel, insurance, or the 55p/mile mileage rate
- Tools and equipment — usually claimed in full via the Annual Investment Allowance
- Public liability insurance
- Trade merchant account fees
- Training courses — unvented cylinders, renewable heating certifications
Best MTD Software for Plumbers
Software links are affiliate, help fund CheckMyMTD. Recommendations based on ease of use for self-employed income tracking.
Frequently Asked Questions
Does an emergency call-out fee count differently to a routine job?
No, however dramatically your pricing varies by urgency or time of day, every payment counts identically towards your qualifying income.
Is my qualifying income the parts price, or my margin after what I paid the merchant?
It's the full amount you invoiced the customer, including parts. What you paid your merchant or supplier is claimed back separately as a business expense, reducing your taxable profit but not your gross qualifying income.
I do some CIS subcontracting alongside my normal plumbing work. Do both count?
Yes, all self-employment income combines into one qualifying income figure, whether it came from direct customer call-outs or CIS subcontract work, though CIS income is assessed on the gross amount before deduction.
Can I claim my Gas Safe registration fee?
Yes, professional registration and renewal fees required for your work are a normal allowable business expense.
Should I use actual van costs or the mileage rate?
Either is allowed, but you need to pick one method per vehicle and stick with it consistently for that vehicle.