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Electrics and gas

Does a home survey service an unvented hot-water cylinder?

No. An unvented cylinder stores hot water under pressure from the mains. It has safety controls a surveyor does not test. Seeing a modern cylinder is not a service record, and a missing record is not, by itself, a leak. The survey can note a stain, a discharge pipe that looks wrong, or a tank in a cupboard it could not reach.

Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.

What is the fuller explanation?

These cylinders are building work when they are installed, often notified through a competent-person scheme. GOV.UK describes that route in general. The certificate, if it exists, is for the solicitor’s file. It does not mean the valves were checked last year. Ask the seller for the commissioning paper and any service.

If you need the controls tested, ask a plumber who is competent for unvented systems, not for a second Level 2. There is no RICS price for that service. A leak from the discharge pipe into a soil stack or out to a visible place is a plumbing defect. It is not a gas certificate and not a survey fail of the whole house.

What should you ask your surveyor?

  • Could you see the cylinder and the discharge pipe?
  • Are you noting the absence of a service, or an actual leak?
  • Was installation paperwork something you expect the solicitor to collect?

What are the typical next steps?

  1. Ask for the commissioning certificate and the last service.
  2. If there is a leak or a warning discharge, get a competent plumber to quote that, not a new bathroom.
  3. Do not turn the controls as a DIY test.

Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.

Also asked about this

Is an unvented cylinder the same as a loft tank?

No. A cold tank in the loft feeds a traditional system. An unvented cylinder is on the mains. The survey should not mix the names.

Does a combi boiler mean there is no cylinder?

Usually a combi heats water on demand and there is no storage cylinder. If both are present, ask the plumber what is actually connected. The survey may not trace it.

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