Do water heater expansion tanks need extra support besides the pipes?
Plumbing codes and inspectors often give conflicting advice on whether an expansion tank can be supported solely by its copper piping or if it requires a separate wall mount. This leaves DIYers uncertain about proper installation, risking unsupported weight stress on the water heater connections.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Using a brass expansion tank tee
- 2Adding a service valve close in line
- 3Mounting the tank facing downward
- 4Eighty-elbowing the expansion tank over to the wall for a separate mounting bracket
- 5Emailing photos directly to the plumbing inspector
- 6Using brass fittings for support if strapping is absent
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Dry fitting all the copper for this electric water heater. CA approved to mount the expansion tank in this fashion?”source ↗
“Not my picture, but yes im planning on doing it like this.”source ↗
“Really wish the inspector would respond to me bc it seems convoluted to elbow the tank over to the wall no?”source ↗
“One plumber said this is fine since it’s stacked over the pipe but idk”source ↗
“This expansion tank is upside down. Second the tank should be supported with something besides the pipes.”source ↗
Where this came up
People with this problem also raised
- 2Temporary fix for a snapped coolant expansion tank nipple
- 4Why is there water on the floor around my new water heater?
- 2Should I remove a water heater stand before epoxy coating?
- 2How do I know what size tankless water heater I need?
- 3Can I replace a hot water heater with a direct swap if ports match?
- 2Are quick-release oil drain valves worth it?