Does a combi boiler need a water tank?

If I switch to a combi boiler, what happens to the existing water tank? Can I make use of it in the system, or do I just get it removed?

Asked by caroline on 4th Feb 2026
Expert Trade Answers
"NO, COMBI BOILER HEAT UP THE WATER INSTANTLY, REGULAR BOILERS AND SYSTEM INSTEAD REQUIRE A WATER CYLINDER"
Answered on 4th Feb 2026 - Member since Jun 2023 - report
"The combi boiler heats water as it's used. The tanks are redundant and no longer used so removed when converting the system usually"
Answered on 4th Feb 2026 - Member since Apr 2023 - report
"All tanks and cylinders are removed. Combi is mains fed"
Answered on 4th Feb 2026 - Member since Aug 2023 - report
"You just do away with it as there’s no use for it. Thanks neil"
Answered on 4th Feb 2026 - Member since Jan 2023 - report
"Hi the combi boiler does not require a hot water tank , you can remove it and make use of the space. Hope it helps"
Answered on 4th Feb 2026 - Member since Feb 2023 - report
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