How to Start a Plumbing Business in the UK (2026): Costs, Gas Safe and First Steps

By Paul Lewis — time-served tradesman with over 40 years in the building services industry, former owner of his own contracting business, and five years teaching apprentices and adult learners in further education.

If you’re a qualified plumber or heating engineer thinking about working for yourself, this guide sets out what you need to do, roughly what it will cost, and what you can expect to earn. It’s written for the UK and uses 2026 figures.

Starting a plumbing business: the checklist

1. Make sure your qualifications and experience are ready for self-employment.
2. Register with Gas Safe if you will do any gas work.
3. Get your G3 unvented qualification and sort out water regulations notification.
4. Choose sole trader or limited company, and register with HMRC.
5. Open a separate business bank account and set up simple bookkeeping.
6. Arrange insurance: public liability as a minimum.
7. Sort out your van, tools and test equipment.
8. Work out an hourly rate that covers all your costs.
9. Find your first customers.

Each step is covered below.

1. Are you ready to go self-employed?

Most successful self-employed plumbers spent several years employed first. Qualifications get you through the door, but customers pay for someone who can diagnose a fault quickly, work in a tight loft or under a floor, and deal with whatever a job throws up. If you’re still finishing your Level 2 or Level 3, finish it and get a few years on the tools before you go it alone.

2. Gas Safe registration

If you work on gas appliances, Gas Safe registration is a legal requirement. Working on gas without it is a criminal offence, and general plumbing qualifications do not cover it.

To register, you need to pass ACS assessments for each type of gas work you’ll carry out, such as boilers, cookers or gas fires. You are only registered for the categories you’ve been assessed in, so check you’ve covered all the work you plan to take on. ACS assessments have to be renewed every five years.

Cost: for 2026/27, a new Gas Safe business registration is £319.96 plus VAT (£383.95), which covers your first year, one engineer and your ID card. After that, annual renewal is cheaper, at around £170–£210 depending on how you renew. ACS assessment fees are on top and vary between centres, so get quotes from two or three.

If you won’t do any gas work at all, you don’t need Gas Safe registration, but you must not touch gas appliances or pipework.

3. Water regulations and unvented hot water

To install or work on unvented hot water cylinders, you need the G3 qualification. Some plumbing work also has to be notified to your water supplier before you start. Joining an approved contractor scheme such as WaterSafe lets you self-certify much of this work and shows customers you’re competent.

4. Sole trader or limited company?

Most plumbers start as sole traders. It’s simple to set up: you register for Self Assessment with HMRC and pay tax on your profits. A limited company can be more tax-efficient once profits grow and protects your personal assets, but it involves more paperwork and accountancy costs.

If you work for builders or main contractors, you’ll also need to register for the Construction Industry Scheme (CIS).

From April 2026, sole traders with income over £50,000 must keep digital records and send quarterly updates to HMRC under Making Tax Digital. Accounting software costs roughly £12–£35 a month and is worth having from day one anyway.

5. Insurance

Public liability insurance is essential. A leak or flood caused by your work can run into thousands of pounds, and most customers, landlords and letting agents will ask for proof of cover before you start. Typical costs in 2026 are:

• Public liability (£2m cover): about £150–£300 a year
• Commercial van insurance: about £800–£1,500 a year
• Tool insurance: about £80–£200 a year
• Professional indemnity: about £100–£200 a year, if you give design advice or specify systems
• Employers’ liability: a legal requirement as soon as you take anyone on

Budget roughly £1,100–£2,200 a year in total.

6. How much does it cost to start a plumbing business?

It depends mainly on what you already own.

If you’re already qualified and have a van and tools, your first-year costs are mostly registration, insurance, software and a little marketing: roughly £3,500–£4,000.

If you’re starting from scratch, a used van (£5,000–£12,000), racking and signage, a full tool kit and test equipment, insurance and registration can push first-year costs to £15,000 or more.

The biggest items are usually:

• Van: a reliable used van at £5,000–£12,000. A new van rarely makes sense when you’re starting out.
• Test equipment: a flue gas analyser alone costs £500–£900 if you do gas work, plus a manometer and calibration certificates.
• Van racking and signage: from a few hundred pounds to £2,000 for a full modular system.

Want the full picture? How to Start Up and Run Your Own Plumbing and Heating Business by Paul Lewis takes you through every step in detail across 52 chapters: registration, pricing, finding customers, health and safety, cash flow, taking on staff and planning your exit. It includes a self-employment readiness check, a sample terms and conditions template, and a chapter-by-chapter action checklist. See inside the book →

7. Starting a plumbing business with little money

You don’t need £15,000 in the bank to start. Many plumbers start lean:

• Use what you’ve got. Keep your existing van and tools, and add only what jobs require.
• Buy test kit before power tools. Test equipment is a legal and safety necessity. Specialist power tools can wait until a job pays for them.
• Subcontract to start with. Working for a builder or larger plumbing firm on a day rate gives you steady income while you build your own customer base.
• Take deposits on bigger jobs. Asking for money up front to cover materials means you’re not funding customers’ boilers out of your own pocket.
• Keep your overheads low until the work is coming in regularly.

8. What can a self-employed plumber earn?

In 2026, self-employed plumbing and heating engineers commonly charge around £50–£60 an hour, or £300–£400 a day, with higher rates in London and the South East and lower in some rural areas.

But your rate is not your income. Out of it come your van, fuel, insurance, registration, tools, software, phone, and the hours you spend quoting, buying materials and doing paperwork, none of which you can charge for. You also have no holiday pay or sick pay.

The most common mistake new plumbers make is setting their rate by looking at what others charge, rather than working out what they need to charge to cover their own costs and make a profit. Work out your true annual costs first, divide by the hours you can realistically bill, and add your profit on top.

9. Finding your first customers

Most steady plumbing work comes from relationships, not advertising:

• Builders and other trades who need a reliable plumber for every job
• Landlords and letting agents who want one number to call for all their properties, including annual gas safety checks
• Past customers who recommend you, so ask every happy customer for a review

Set up a free Google Business Profile on day one. It’s the first thing many local customers see when they search for a plumber. Answer enquiries quickly and send clear written quotes, because the plumber who replies first often gets the job.

For a full guide to finding and keeping customers, see our marketing guide for trade businesses. If you want to bid for housing association or council maintenance contracts, see Winning Work: the guide to tendering.

Frequently asked questions

Do I need to be Gas Safe registered to start a plumbing business? Only if you will work on gas appliances or pipework. Plumbing-only businesses don’t need it, but you must not carry out any gas work without it.

How much does it cost to start a plumbing business in the UK? From about £3,500 in the first year if you already have a van and tools, up to £15,000 or more if you’re buying everything.

Can I start a plumbing business without being a plumber? You can own one and employ qualified plumbers, but you’ll need registered engineers for any gas work, and you’ll be responsible for the quality and safety of the work done in your business’s name.

How much do self-employed plumbers earn? Rates of £50–£60 an hour are common in 2026, but take-home pay depends on your costs, how many hours you can bill, and whether your prices cover both.

Should I be a sole trader or a limited company? Most plumbers start as sole traders because it’s simpler. A limited company can make sense once profits grow. Speak to an accountant before you decide.

Ready to start?

Starting a plumbing business is far easier when you know what’s coming. How to Start Up and Run Your Own Plumbing and Heating Business covers everything in this guide in full, from your first registration to growing a team.

See inside the book →

Figures are typical 2026 costs and are a guide only. Check current fees with Gas Safe Register, HMRC and your insurer before you start.