How to start a plumbing business in the UK

You can legally start a plumbing business in the UK with no licence at all. WaterSafe's director says anyone can call themselves a plumber, with no legal need for qualifications or experience.

That doesn't mean you can do any job. Gas work, unvented cylinders and some electrical work all have rules. And customers are nervous: in a 2026 Citizens Advice survey, 28% of people who arranged repairs did the work themselves, and 26% delayed or avoided it, because they couldn't find a trader they trusted.

So proof is your first marketing tool. Here's what to set up, in order.

Step 1: Know what you can and can't do

Gas Safe registration covers only the work areas where you hold evidence of competence. Being a plumber doesn't cover all gas work by default.

Unvented cylinders are often described as needing a "G3 ticket". The guidance actually talks about showing competence through a competent person scheme or a current registered operative skills card. If you're unsure which you hold, ask your training provider.

Is it worth joining an approved contractor scheme?

For most new businesses, I'd say yes. Schemes are voluntary, but they do three useful things:

• Approved contractors can self-certify some work, though only some. Most notifiable items, including pumps and larger baths, still need notifying.
• WaterSafe lists members on a free public search, and it costs nothing extra once you've joined a scheme and opted in.
• In England and Wales, an owner or occupier may have a defence against prosecution where an approved contractor did and certified the work. If you use that on a quote, keep to those words.

WaterSafe needs £2 million of public liability cover, plus £5 million of employers' liability where it applies. Employed plumbers need at least NVQ Level 2 and a water fittings qualification.

Step 2: Check your qualifications

The main route in England is the Level 3 Plumbing and Domestic Heating Technician apprenticeship, which typically takes 48 months plus assessment. Its gas option lets apprentices meet the requirements for Gas Safe registration during assessment. The standard is being revised, so check the current version.

Experienced plumbers can take a Level 3 NVQ Diploma, according to the GoConstruct careers site. There's also a shorter Level 2 foundation apprenticeship, which began in 2025.

Step 3: Choose sole trader or limited company

Most people can start as a sole trader and change later. Speak to an accountant if you're taking on staff, signing big contracts or making good profits, because the tax position varies. That's a question for someone who can see your numbers.

Step 4: Sort out tax

• Self Assessment: you can start trading before you register, but you must register if you earn over £1,000 in a tax year. The deadline is 5 October after the tax year ends. If you start in this tax year, that's 5 October 2027.
• Records: keep them from day one, including every receipt.
• VAT: you must register if taxable turnover passes £90,000 in any 12 months.
• Mileage: the simplified rate for cars and goods vehicles rose to 55p a mile for the first 10,000 business miles, backdated to 6 April 2026. Check with your accountant if it fits your van.

Making Tax Digital

If you're a sole trader, you'll need compatible software and quarterly updates once you're in scope. The test uses gross self-employment and property income, before expenses.

Choose accounting software that handles this from the start. It's far easier than moving a year of records later.

The Construction Industry Scheme

CIS catches plumbers out in both directions.

• Householders aren't contractors, so a domestic job for a homeowner is outside CIS.
• If you subcontract to a builder or a contractor, you should register. They deduct 20% from your labour if you're registered and verified, 30% if you're not, and nothing if you hold gross payment status.
• Materials you paid for directly aren't subject to the deduction, so keep your invoices clear.
• If you pay other trades for construction work, you can become a contractor yourself, with monthly returns.

HMRC's manual says replacing a central heating boiler isn't installing a heating system, and that the system rule doesn't cover repairs. Mixed jobs can be less clear, so check any job that's part of a bigger contract.

Step 5: Get insured

• Public liability: not a legal requirement, but water schemes and many customers require it. A leak can cost far more than the job.
• Employers' liability: needed as soon as you employ someone, with at least £5 million of cover. Fines reach £2,500 a day without it. There's an exception if you only employ a close family member.
• Tools and van: not covered by public liability, so check what you need.

Step 6: Set up how customers reach you

This is the step I'd expect most new plumbers to skip. They do good work, then lose it on the phone. A 2026 YouGov survey for Answer4u found 37% of UK adults would abandon a call to a business within 60 seconds, and only 6% would leave a voicemail.

You're on your own, with your hands in a cupboard. So set this up before you buy adverts:

1. A separate business number, so work doesn't vanish into your personal phone.
2. A text-back on missed calls, so nobody gets silence.
3. A free Google Business Profile, with your real service area and hours.
4. A simple website with your services, area, registration numbers and a way to contact you.
5. A way to ask every customer for a review.

Our text templates give you the words for free.

Step 7: Find your first customers

In the Citizens Advice survey, 36% of people who used a trader found them through someone they knew. So start there, then widen out.

1. Tell everyone you know, with a clear message about what you do and where.
2. Ask local builders, kitchen fitters and bathroom fitters what work they turn away.
3. Ask for a review after every job, starting with your first. Ask every customer, not only the happy ones.
4. Add lead sites if your diary has gaps. Read lead sites or your own leads before you sign a 12-month deal.
5. Price properly from day one. Our pricing guide shows you how.

Your first 30 days

• Choose your legal structure and register with HMRC.
• Open a separate bank account.
• Buy public liability insurance.
• Join an approved contractor scheme, and Gas Safe if you do gas work.
• Get a business number with a missed-call text-back.
• Set up your Google Business Profile.
• Write your price list and quote template, with the cancellation notice.
• Choose accounting software that works with Making Tax Digital.

David Bell, founder of Real Business Systems

David helps small UK businesses get found, answer every enquiry and keep customers coming back. We sell some of the services mentioned here, and we say so where they come up.