How to start a plumbing business (even if you're not a plumber)

People come to this question from two directions. Some are plumbers who've had enough of making money for someone else. Others have never soldered a joint in their lives but can see that good plumbers are booked up for weeks and think there's a business in that. Both can work, but they're very different starts.

This guide covers how to start a plumbing business in the UK either way: the rules on gas, water and hot water, registering the business, insurance, pricing and finding your first customers. There's a section on starting a plumbing business without being a plumber too. The legal points are checked against gov.uk, Gas Safe Register, WaterSafe and the trade bodies as of October 2026.

For the record, I'm not a plumber either. I build websites and do SEO for trades, so the marketing end is where I'll give you opinions. Everything else is sourced.

The rules every plumbing business has to follow

There's no general licence to be a plumber in England. Anyone can call themselves one. But three areas come with real legal requirements, and they decide what work your business can take on.

Gas: Gas Safe Register

By law, anyone doing gas work for money must be on the Gas Safe Register, and registration runs through a business. Each engineer holds ACS qualifications for the types of gas work they do, and the business registers its engineers. When I checked Gas Safe's fees page in October 2026, a new business application was listed at £269 plus VAT (covering one engineer), with each additional engineer at £34.15 plus VAT and online renewal at £185 plus VAT (Gas Safe Register).

Installing or replacing a gas boiler is notifiable building work. The Gas Safe engineer notifies it, and the customer gets a Building Regulations Compliance Certificate.

Water: the Water Fittings Regulations and WaterSafe

All plumbing work connected to the mains has to meet the Water Supply (Water Fittings) Regulations 1999, and some jobs have to be notified to the water company before you start. Join an approved contractor scheme and you can do certain work without that prior notice, and issue a certificate of compliance to the customer. The approved contractor schemes sit behind WaterSafe, the national register of approved plumbers, and include WIAPS, APHC, CIPHE and SNIPEF.

Unvented hot water and other notifiable work

Fitting an unvented hot water cylinder is notifiable under Part G3 of the Building Regulations, and only someone with the right G3 qualification should do it. Through a competent person scheme you can self-certify it rather than calling in building control. The government's list of authorised schemes for heating and hot water includes APHC, BESCA, Blue Flame Certification, Certsure, HETAS, NAPIT and OFTEC, with Gas Safe Register covering gas work (gov.uk).

Bathrooms are a mix. Like-for-like swaps generally aren't notifiable, but changing drainage can be, and electrical work near baths and showers falls under Part P.

How to start a plumbing business in the UK: registering and tax

Most plumbers start as sole traders. Register for Self Assessment with HMRC once you earn over £1,000 in a tax year, by 5 October after the end of the tax year you started (gov.uk). A limited company costs £100 to register online at Companies House, and directors verify their identity through GOV.UK One Login. If you're not a plumber and plan to employ engineers, a limited company is often the neater fit, but get an accountant's view on your situation.

As of October 2026:

• Making Tax Digital for Income Tax applies to sole traders with qualifying income (turnover, not profit) over £50,000 since April 2026, £30,000 from April 2027 and £20,000 from April 2028 (HMRC). Boilers and parts push turnover up fast.
• VAT registration is compulsory once taxable turnover passes £90,000 in a rolling 12 months (gov.uk).
• CIS applies if you install water or heating systems as a subcontractor for a builder: 20% deducted from your payments if you're registered, 30% if you're not.

Insurance

• Public liability. Not legally required, but it's the policy that pays when a fitting lets go and floods a kitchen, so don't start without it.
• Employers' liability. A legal requirement once you employ anyone, with at least £5 million of cover. The fine for not having it can be £2,500 for every day (gov.uk).
• Tools, stock and van. A van full of fittings and a few boilers is worth stealing. Check the overnight storage terms.
• Professional indemnity if you'll design heating systems or give advice people rely on.

How to start a plumbing business without being a plumber

You can own and run a plumbing business without being a plumber. Plenty of trade businesses are run by people who handle the phones, quotes, money and marketing while qualified engineers do the work. What you can't do is the regulated work itself, or sign it off.

What that means in practice

• Gas work needs Gas Safe registered engineers working for your registered business. Without one, you can't take on boilers, cookers or gas fires at all.
• Unvented cylinders and other notifiable work need people with the right qualifications and a competent person scheme, or building control on every job.
• Your reputation rests on work you can't judge. Find a technical lead you trust completely, ask for photos of every finished job, and follow up with customers yourself.

Hiring your first engineer

Decide early whether engineers are employees or subcontractors, because the law looks at how the relationship actually works, not what you call it. HMRC has a free check employment status for tax tool. If you employ people, you must register as an employer with HMRC before the first payday (gov.uk), take out employers' liability insurance, check their right to work, and set up a workplace pension where the auto-enrolment rules say so.

The honest numbers

This is the bit people skip. Made-up figures to show it: say an engineer costs the business £280 a day once you add wages, employer's National Insurance, pension, van, fuel, insurance and tools. If they're on paid work four days in five, every paid day has to bring in £350 before parts and before you've earned a penny. Your own wage comes after that. It can work, but only with tight scheduling, fair prices and very few wasted trips.

Your job as the owner

If you're not on the tools, your value is everything the plumbers don't want to do: answering the phone every time, quoting the same day, booking jobs so the vans aren't criss-crossing town, chasing invoices and asking for reviews. Customers notice all of that. A plumber under a sink can't answer a call. You can, and an answered phone wins work on its own.

Mistakes I'd avoid

• Advertising gas work before you have a registered engineer. Not even "coming soon". Your business can't legally do that work yet, and someone will ring asking for it.
• Underpricing to win jobs and then having no margin left to pay a good engineer properly.
• Relying on one engineer. If they leave, so does your business. Keep a trusted subcontractor in reserve.
• Promising response times you can't keep. "Within the hour" on your website becomes a one-star review the first time the van's stuck on the motorway.

The other route is buying an established plumbing business, with engineers, customers and a phone number that already rings. It costs more up front, but you're buying something that works rather than hoping it will.

Tools, van and stock

If you're the plumber, you've probably got most of the tools already. The new costs are usually a van that's set up properly with racking, a sensible stock of the fittings you use every week (so you're not driving to the merchant for every job), and any testing kit your registrations need, such as a calibrated flue gas analyser for gas work. Open trade accounts with a couple of merchants, and keep on top of what's in the van. Dead stock is cash sat on a shelf.

Pricing plumbing work

Plumbers price in three main ways, and most businesses end up using all of them:

• Fixed prices for common jobs like tap replacements, toilet repairs and combi swaps. Customers like knowing the price, and you stop losing money on jobs that drag.
• Hourly or half-day rates for fault-finding, where nobody knows how long it'll take. Set a minimum charge so a ten-minute job still covers the trip.
• Written quotes for bigger work like bathrooms and heating systems, stating what's included, what isn't and how extras are charged.

Work out your daily floor first: what you need to earn plus your running costs, divided by the days you'll realistically be paid for. Then mark up parts, charge more for out-of-hours call-outs, and review prices every year. And if you agree a job in the customer's home, they usually get 14 days to cancel under the Consumer Contracts Regulations, which you must tell them in writing.

Getting your first plumbing customers

Plumbing customers are either in a hurry (a leak, no hot water) or planning (a new bathroom, a boiler swap). The first group rings whoever they find first. The second group checks you out properly. You need to be ready for both.

A name and a Google Business Profile

Pick a name people can remember and spell. My guide to trade business name ideas covers the checks. Then get on the map with a free Google Business Profile, which is where plenty of urgent plumbing searches end up. Here's how to set up a Google Business Profile properly as a business that goes to customers.

A website that shows you're registered

Put your Gas Safe registration number and any scheme memberships where customers can see them. Customers can check the Gas Safe Register themselves, and some do. A simple website with your services, prices for common jobs, the areas you cover and real photos covers the planners. If you're not sure, read do I need a website, and here's how I approach websites for plumbers.

Reviews and, later, SEO

Ask every customer for a Google review before you leave. Lead sites can fill early gaps, but read my breakdown of where plumbing leads come from and what they really cost first. Once the basics are in, ranking for "plumber in Rotherham" or "boiler repair Sheffield" is the next step, which is where SEO for plumbers comes in. More on my marketing for plumbers page.

Questions about starting a plumbing business

Can you start a plumbing business without being a plumber?

Yes. You can own and run it, but gas work must be done by Gas Safe registered engineers working for your registered business, and other regulated work needs qualified people. The sensible first step is hiring an experienced engineer you trust.

Do you need to be Gas Safe registered to be a plumber?

Only for gas work. A plumber who sticks to water, drainage and bathrooms doesn't need Gas Safe registration, but can't touch gas boilers, hobs or fires.

How much does it cost to start a plumbing business?

If you're a plumber with tools and a van, the main costs are insurance, registrations and stock: Gas Safe was listed at £269 plus VAT for a new business in October 2026 if you'll do gas work, and £100 for a limited company online. Without being a plumber, add your first engineer's wages, a van and tools for them, and enough cash to cover a few slow months.

Where I come in

I can't fix your boiler, but I can make sure people looking for a plumber in your area find you and ring you. I build trade websites personally: £497 one-off, no VAT, no deposit, and you see your homepage design within 24 hours of the set-up call before you pay anything. Hosting and your web address are £20 a month, paid by you.

Starting out? Get your free website mockup and see what your plumbing business could look like online. If I think a website can wait, I'll tell you.