Guide
Plumbing qualifications and accreditation in the UK
One credential is a legal requirement and the rest are voluntary. Knowing which is which tells you what a badge on a van is actually worth.
The one that is the law
Gas Safe registration. Any work on gas pipework or a gas appliance in the UK must be carried out by an engineer on the register, and working outside it is a criminal offence. It is per engineer and per appliance category, the card lists the categories, and the register is public and free to search.
Everything else in this guide is voluntary, useful, and not a legal requirement.
The qualifications behind the trade
The standard route is an NVQ or SVQ Level 2 and 3 in Domestic Plumbing and Heating, usually through an apprenticeship, or the equivalent City and Guilds and EAL diplomas. Gas work adds the Accredited Certification Scheme assessments, renewed every five years, which is what registration is built on.
Separate tickets sit on top for specific work. G3 covers unvented hot water systems. Water regulations approval covers work notifiable to water companies. MCS certification is required for a heat pump installation to qualify for the Boiler Upgrade Scheme grant. F-Gas covers refrigerant work inside heat pumps and air conditioning.
The voluntary bodies, and what they mean
CIPHE, the Chartered Institute of Plumbing and Heating Engineering, is the trade's professional body, and membership grades reflect qualifications and experience. APHC and the SNIPEF in Scotland are trade associations with their own vetting. WaterSafe is an umbrella scheme listing plumbers approved under water industry schemes, which matters for work notifiable to a water company.
TrustMark is a government endorsed quality scheme covering several trades. Which? Trusted Traders and Checkatrade run their own vetting, which is real but is a commercial listing rather than a qualification.
What a badge on a van is worth
A Gas Safe number is a fact you can check in a minute. A membership number for CIPHE, WaterSafe, TrustMark or an approved contractor scheme is also checkable, and worth checking, because logos are easy to print.
What none of them tells you is whether the person is good at the specific job you have. For that, the useful signals are whether they ask questions before quoting, whether the quote names parts and models, and whether they can explain what they will do when they find something unexpected.
Insurance, which people forget to ask about
Public liability insurance is not a legal requirement for a sole trader, and most carry it anyway, typically at one, two or five million. It covers damage caused by the work, and an escape of water in a flat can reach a number worth insuring against.
Ask to see the certificate rather than the logo, and check the expiry date. For work in a managed block or a commercial property, the managing agent will usually specify a minimum level.
Common questions
Do plumbers have to be qualified?
Gas work legally requires Gas Safe registration. General plumbing has no equivalent legal requirement, though the recognised route is an NVQ Level 2 and 3 through an apprenticeship.
What is WaterSafe?
An umbrella scheme listing plumbers approved under water industry approved contractor schemes. It matters for work that has to be notified to a water company.
Is Checkatrade a qualification?
No. It is a commercial listing with its own vetting process. It is useful evidence, and it is not a substitute for checking Gas Safe registration.