# Accounting for plumbers and heating engineers

Canonical: https://taxmo.co.uk/trades/plumbers
Last updated: 2026-11-06

Parts bought on the way to a job, call-outs invoiced the same day and a van that doubles as a workshop: plumbing generates a lot of small records. Taxmo turns them into one set of books you can check at any point in the year.

## What Taxmo does for plumbers

- Income and expenses in one place: Record what you earn and spend in categories, and see your profit and what to set aside for tax as you go. On every plan.
- Receipt scanning: Photograph a receipt or forward it on WhatsApp, and Taxmo reads it into an expense for you to check. On Starter and Pro.
- Connect your bank: Connect your bank read-only or upload a CSV statement. Each transaction waits for your approval before it counts. On Starter and Pro.
- Invoices and quotes: Send quotes and invoices from the same records, and see which invoices are still unpaid. A few a month on Free, without a cap on Starter and Pro.
- Mileage log: Log business journeys and Taxmo applies HMRC's approved mileage rates for the tax year, including the lower rate once you pass the annual mileage band.
- Reverse charge invoices: Mark an invoice line as reverse charge and the invoice shows the rate, charges no VAT and states that your customer accounts for it.
- VAT returns, once you are registered: Taxmo works out the nine boxes from your approved entries, shows where each figure comes from and files the return to HMRC over Making Tax Digital. On Starter and Pro.
- Capital allowances: Keep a register of the assets you claim capital allowances on, with the annual investment allowance and writing down allowances worked out for each. On Pro.

## Expenses plumbers commonly claim

- Materials: Raw materials and the direct costs of the work you sell. Anything bought for private use is not allowable. Source: https://www.gov.uk/expenses-if-youre-self-employed/reselling-goods
- Equipment you keep: Equipment you keep and use in the business is claimed as an allowable expense if you use cash basis accounting, or through capital allowances if you use traditional accounting. Source: https://www.gov.uk/expenses-if-youre-self-employed/office-property
- Van running costs: Fuel, insurance, repairs and servicing, vehicle tax, breakdown cover and parking for business journeys. Or use the flat mileage rate instead of actual costs, unless you have already claimed capital allowances on the vehicle. Source: https://www.gov.uk/expenses-if-youre-self-employed/travel
- Protective clothing: Protective clothing your work needs, such as safety boots or hard hats, and overalls that protect your own clothes. Everyday clothing is not allowable, even if you only wear it for work. Source: https://www.gov.uk/expenses-if-youre-self-employed/clothing
- Business insurance: Any insurance policy for the business, for example public liability insurance. Source: https://www.gov.uk/expenses-if-youre-self-employed/legal-financial
- Training: Courses that improve skills you already use in the business or keep you up to date with your industry. Training to start a new business, or to move into an unrelated area, is not allowable. Source: https://www.gov.uk/expenses-if-youre-self-employed/training-courses
- Phone and internet: The business share of phone, mobile and internet bills. Only the business part of a mixed-use bill counts. Source: https://www.gov.uk/expenses-if-youre-self-employed/office-property

## Rules worth knowing

- The Construction Industry Scheme: If you work for a contractor in construction, you may need to register for CIS as a subcontractor. The contractor takes a deduction from each payment and passes it to HMRC as an advance payment towards your tax and National Insurance. Registering means a lower deduction than not registering, and some subcontractors can apply for gross payment status. Source: https://www.gov.uk/what-you-must-do-as-a-cis-subcontractor
- VAT domestic reverse charge: If you are VAT-registered, most building and construction services between VAT-registered businesses that are reported under CIS use the domestic reverse charge: your customer accounts for the VAT instead of paying it to you. Some services supplied on their own are excluded, so check the list on GOV.UK. Source: https://www.gov.uk/guidance/vat-domestic-reverse-charge-for-building-and-construction-services

Current figures, each with its GOV.UK source: https://taxmo.co.uk/uk-tax-rates

## Common questions

### Are parts I fit for a customer an expense?

Materials and the direct costs of the work you sell are allowable. Anything bought for private use is not, so keep receipts for parts separate from personal purchases.

### Do I charge VAT on work for homeowners?

Only if you are VAT-registered. The domestic reverse charge is for supplies between VAT-registered businesses reported under CIS, so work for a homeowner follows the normal VAT rules. Check your own position on GOV.UK.

### Can I use the trading allowance and claim expenses?

No. The trading allowance is a tax-free amount of trading income each year, and if you use it you cannot also claim expenses or capital allowances. Check the current amount on GOV.UK or on our UK tax rates page.

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General information from GOV.UK guidance, not tax advice. Rules and figures change, so verify on GOV.UK using the links on this page before relying on them.