How to check a plumber is Gas Safe or WaterSafe registered
Gas work must be done by a Gas Safe registered engineer. How to check their card, when to look for WaterSafe, and what certificate to expect.
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Hiring someone for boiler or pipework means letting a stranger into your home to alter systems that carry gas and drinking water. Two registers exist to help you check them first: the Gas Safe Register for gas, and WaterSafe for water. This guide explains what each one covers, how to check an engineer in a few minutes, and what paperwork to expect afterwards. Guidance on this page was checked on 11 October 2026.
Which register covers which job?
Gas work must be done by a Gas Safe registered engineer. HSE's domestic gas FAQs say anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer and competent in that area of gas work. HSE's landlord guidance adds that installing or reinstalling a gas appliance counts as gas work. If a job touches gas, ask for a Gas Safe registered engineer before you agree anything.
Water work is different. The WaterSafe Register describes itself as a free online directory and national accreditation body for plumbers, water supply pipe installers and other water services specialists. Its approved contractors are trained in the Water Fittings Regulations and can issue a Certificate of Compliance.
| Job | Register or scheme to check | Why |
|---|---|---|
| Boiler installation, gas fire, gas hob, gas pipework | Gas Safe Register | HSE treats installing or reinstalling a gas appliance as gas work for a Gas Safe registered engineer |
| Oil boiler | A competent person scheme such as OFTEC, APHC or Certsure | GOV.UK lists these schemes for oil appliances |
| New bathroom, taps, water supply pipework | WaterSafe Register, or an APHC, BESCA, Certsure, HETAS or NAPIT member | WaterSafe covers the Water Fittings Regulations; GOV.UK lists those schemes for bathrooms and water supply |
| Heating system or controls | A scheme listed by GOV.UK for heating, including Gas Safe Register for gas systems | Lets the installer self-certify the work |
Many jobs involve both. A new combi boiler is gas work and also touches the water system, so ask the installer how they cover each part. In this guide, "engineer" means someone registered for gas work and "plumber" means someone working on water and heating pipework. Some people are both.
How to check a Gas Safe engineer
Do the check before anyone starts work, not after the invoice arrives.
- Ask to see the engineer's Gas Safe Register ID card when they arrive. HSE says all registered engineers carry ID cards that show which appliances they are qualified to work on, and it strongly encourages checking the card before work begins.
- Turn the card over. HSE says the area of gas work an engineer is competent in is marked on the back of the card, and it advises checking that this matches the work you need.
- Check the licence number on the Gas Safe Register website. HSE says its Check an Engineer service shows the engineer's photo and qualifications. You can also ring the helpline on 0800 408 5500, or text the word Gas and the seven-digit licence number to 85080 to be told whether it is registered (HSE).
- Tell the engineer which fuel and appliance you have, whether natural gas or LPG. HSE advises checking that the engineer is competent in that specific area of gas work, and LPG appliances carry the same duties as natural gas ones.
- Get the quote in writing, with the name and registration number of the person who will do the work.
If the card is missing, damaged or does not cover your appliance, rebook with someone who can show you the right one. Booking a different engineer is a small inconvenience compared with an unsafe installation.
How to check a WaterSafe plumber
The WaterSafe search takes a postcode and the type of service, then lists approved contractors near you. WaterSafe says a qualified plumber should hold at least an NVQ Level 2 in Mechanical Engineering Services (Plumbing) or an equivalent, plus a recognised Water Fittings Regulations qualification, and that approved contractors can carry out some work without notifying the water supplier beforehand.
Responsibility matters here too. Ofwat's household guidance says you are responsible for the drains, water pipes and plumbing fixtures on your property, and for making sure your plumbing meets the required standards. Ofwat also says it is not responsible for regulating plumbing. In practice that puts the checking on you, which is why a registered installer with a certificate is worth looking for.
Competent person schemes and the certificate you should keep
Some work needs building regulations approval, and an installer on a competent person scheme can self-certify it and arrange your certificate. GOV.UK's list of competent person schemes links to each register, so you can check that someone belongs to one. Our companion guide explains when plumbing and heating work needs building regulations approval, what the certificate is and when to expect it.
A worked example: a combi boiler swap and a new shower room
Say you are replacing a gas combi boiler and adding a shower room in the same job. The checks split into three parts:
| Part of the job | Who to check | What to ask for |
|---|---|---|
| Fitting the boiler and any gas pipework | A Gas Safe registered engineer | The ID card, with the back showing the right type of gas work |
| New shower, taps and water pipework | A WaterSafe approved plumber, or a competent person scheme member | Their register entry and a compliance certificate |
| Heating system change as a whole | A scheme listed by GOV.UK for heating | Written confirmation of who will arrange the certificate |
If one firm does all three parts, ask them to say which registration covers which part, in writing.
Practical warning signs
These are our editorial suggestions, not legal tests. Be cautious if an installer:
- cannot or will not show an ID card or give a registration number;
- cannot say which scheme certifies their work, or says none does;
- gives a price only verbally and will not put the scope of the job in writing;
- suggests leaving out the paperwork or the notification to the council to save time.
If a bathroom or kitchen refit is being run by a main contractor, ask who is doing the gas and water work and check that person in the same way. If you are still looking for a contractor to manage the whole project, MyLocalBuilders is a sister directory of UK builders. For a plumber or heating engineer, you can browse plumbers by city or look at the boiler installation page.
If you smell gas
HSE's advice is to call the National Grid Gas Emergency freephone number, 0800 111 999, open doors and windows and, if you know where it is, shut off the gas at the meter control valve. HSE's domestic FAQs also say it is illegal to use a gas appliance you suspect is unsafe: turn it off and leave it until a Gas Safe registered engineer has checked it.
Common questions
Is a Gas Safe engineer the same as a plumber?
No. Gas Safe registration covers gas work. A plumber who fits taps, pipes and bathrooms may or may not also be Gas Safe registered, so check each register for the work you need.
What should I do if I smell gas?
HSE advises calling the National Grid Gas Emergency freephone number, 0800 111 999, opening doors and windows and shutting off the gas at the meter control valve if you know where it is. Do not use an appliance you think is unsafe.
Where do I find the certificate for work already done?
Ask the installer who did the work. If they were registered with a competent person scheme, the scheme should issue a certificate, and GOV.UK says that should arrive within 8 weeks of completion.
Sources
- HSE: Domestic gas, frequently asked questions, accessed 11 October 2026.
- HSE: Check an engineer, are they Gas Safe registered?, accessed 11 October 2026.
- HSE: Gas safety, landlords and letting agents (FAQs), accessed 11 October 2026.
- WaterSafe Register: homepage and FAQs, accessed 11 October 2026.
- GOV.UK: Building regulations approval, use a competent person scheme, accessed 11 October 2026.
- GOV.UK: Competent person scheme, current schemes, accessed 11 October 2026.
- Ofwat: Responsibility for pipes and pumping stations, accessed 11 October 2026.
We name the page behind each figure and date it. This guide is general information, not legal or professional advice. Rules can change, so check the linked pages for the current position. Spotted a mistake? Email [email protected] and we will correct it. Posts are written by the MyLocal Network editorial team; see the about page for how the directory works.
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