G3 Qualified Engineer: How to Check Before You Book

Most people only ask whether an engineer is G3 qualified after something has gone wrong: a tundish that will not stop dripping, a warranty claim that was turned down, or a buyer's solicitor asking for a certificate nobody can find. It is much easier to check before the work starts. This guide is the practical companion to our plain-English explanation of the G3 regulations. That article covers what the rules require of the cylinder itself. This one covers the people and the paperwork: how to confirm an engineer's qualification is real and current, what competent person scheme registration adds, and which documents you should be holding once the job is done.

Everything below applies to unvented (mains pressure) hot water storage in England.

What the G3 Qualification Is and Who Awards It

"G3" is shorthand taken from requirement G3 of the Building Regulations, which deals with hot water supply and systems. The guidance in Approved Document G says that a hot water storage vessel of more than 15 litres without a vent pipe to atmosphere should be installed, commissioned, inspected and serviced by a competent person. In the trade, the qualification that shows that competence is called the G3 ticket.

There is no single "G3 certificate" with one official name. The two you are most likely to see in London are:

• BPEC Domestic Hot Water Storage Systems (Unvented). Successful candidates receive a certificate and a competency card. BPEC states the certificates are valid for five years.
• LCL Awards Hot Water Systems and Safety (HWSS), including unvented. LCL Awards lists a five-year certificate expiry and says the certificate is recognised by competent person schemes that allow installers to self-certify hot water work. It covers unvented systems up to 500 litres and 45kW.

Both are renewed by reassessment. BPEC and LCL Awards each allow reassessment for engineers whose qualification expired within the previous 12 months. The key point for you as a customer is simple: the qualification is personal to the engineer and it has an expiry date. A card that was valid when your cylinder was fitted in 2019 proves nothing about the engineer who turns up in 2026.

How to Check an Engineer's G3 Card

Ask to see the card before any work starts. A genuine engineer will not mind; it takes ten seconds. Then work through this checklist:

1. Name. The name on the card should match the person in front of you.
2. Awarding body. Look for the body that issued it, such as BPEC or LCL Awards. Note it down.
3. Scope. The card should refer to unvented hot water storage or hot water systems and safety. A water regulations card or a general plumbing NVQ is not the same thing.
4. Expiry date. Both main qualifications last five years. If the date has passed, the engineer is not currently qualified for unvented work.
5. Certificate number. Photograph the card or write the number down. You need it to verify the certificate and it should also appear on your commissioning paperwork.
6. Confirm with the awarding body. LCL Awards will confirm whether a certificate is valid, has been withdrawn or is subject to conditions. Its verification page asks for the certificate type, the holder's full name and the certificate number. For a BPEC card, contact BPEC's certification team on 01332 376000.
7. Check the business as well as the person. Search the company on the LABC Front Door "Find a Competent Person" tool, which lets you search by postcode or business name and filter by trade such as heating or plumbing.

If the engineer also works on your boiler, check their Gas Safe registration separately. A G3 card does not cover gas work.

G3 Qualification vs Competent Person Scheme Registration

The G3 qualification shows that an individual engineer has been trained and assessed on unvented hot water systems.

Competent person scheme (CPS) registration deals with the Building Regulations paperwork. Approved Document G says that installing an unvented system is notifiable building work, which must be notified to Building Control before work starts. The exception is where the installer is registered with a competent person scheme for unvented hot water work. In that case, the installer self-certifies that the work complies, and the owner or occupier receives a Building Regulations compliance certificate, usually issued by the scheme operator.

The operators listed on GOV.UK for heating and hot water system work include APHC, BESCA, Blue Flame Certification, Certsure, Gas Safe Register, HETAS, NAPIT and OFTEC. Approved Document G advises owners to choose installers with the right skills for unvented work, and gives two examples of how those skills can be shown: registration with a competent person scheme for this type of work, or a current registered operative skills card for unvented hot water systems.

You may also see the WaterSafe logo. WaterSafe is a register of approved plumbing businesses under the Water Fittings Regulations. It is worth having, but it is not one of the Building Regulations competent person schemes listed on GOV.UK.

The best answer is an engineer with a current G3 card, working for a business registered with a competent person scheme. If the business is not registered, Building Control has to be notified before the cylinder goes in. Ask who is doing that, in writing.

The Paperwork You Should Receive

Here is what to expect, and when.

There is one more thing to check that people rarely notice. Approved Document G says every unvented unit should carry a permanent warning label with an "Installed by" panel for the installer's name, address, telephone number and completion date. If that panel is blank on a cylinder that is supposedly new, ask why.

Warranty terms vary by brand. Megaflo, for example, requires the annual service to be carried out by a competent person or a Heatrae Sadia approved engineer. Our cylinder warranty comparison sets out the service conditions brand by brand, and our guide to the annual unvented cylinder service explains what each visit should record.

If the certificate has not arrived within 30 days, Heatrae Sadia's guidance is to contact the competent person scheme operator your installer is registered with. If you lose a competent person certificate later, ask the scheme operator for a copy rather than the council. You will need to know who did the work and roughly when.

Red Flags Before and After the Job

• "The ticket is in the van", and it never appears. Do not let the work go ahead.
• An expired card, or a card for a different qualification entirely.
• The name on the card belongs to someone else at the firm who will "sign it off later".
• No answer on Building Control. The installer cannot tell you which scheme they are registered with, or who is notifying the local authority.
• A blank or missing Benchmark checklist at handover, or one with no registered operative ID number.
• No compliance certificate after 30 days on a job the installer said would be self-certified.
• Visible shortcuts, such as a discharge pipe from the tundish that disappears behind a kitchen unit, or safety valves that have been capped or taped. Our G3 regulations guide explains what the discharge route should look like.

If Your Cylinder Was Fitted by Someone Unqualified

This often comes to light during a sale or on a first service visit. Work through it in this order:

1. Make it safe first. Book a G3 qualified engineer to inspect the cylinder, the safety devices, the expansion vessel and the discharge pipework. Safety comes before paperwork.
2. Look for the records. Check the "Installed by" label, any Benchmark checklist, and any certificate. If there was a registered installer, the scheme operator may be able to issue a copy certificate, provided you know who did the work and roughly when.
3. Talk to Building Control. Where work was done without Building Regulations approval, the route is a regularisation application to your local authority. Only a local authority can grant one. They may need to inspect, open up or test the work, and you may need to make alterations before they issue a regularisation certificate.
4. Check the warranty position with the cylinder manufacturer. Most warranties depend on correct installation to the manufacturer's instructions and on regular servicing.
5. If you are selling or buying, tell your conveyancer early. Where certificates cannot be found, a title indemnity policy is sometimes suggested, but it does not make an unsafe installation safe.

Our G3 unvented cylinder engineer service covers installs, annual services and safety-valve repairs. Ask to see the card when we arrive. For repairs and replacements across every major brand, see unvented cylinders London.

FAQs

Save the number: 0207 046 1363 or WhatsApp 07456 975436. Whether you need a new unvented install, an annual service or a second opinion on a cylinder with no paperwork, ask for a G3-qualified engineer and ask to see the card.

John Alexander N., Director, Emergency Repairs London