I have an electric breaker panel in the bedroom closet.

On the other side of this wall is a hall closet.

I want to move my hot water heater into this closet however the contractor says that it's not good to have a water heater share a wall with a breaker box in case something happens. He recommends demo ing the closet drywall and re building it out with hardi backer to protect the breaker box.

I can find nothing in code that says this is necessary and can't really see any likely circumstance the water heater might damage the breaker box.

Question is this against code and/or is it a bad idea?

I live in California in a single family home.


  • 1
    Hello, and welcome to Stack Exchange. Is this the usual stand-alone cylindrical heater, or is it a hang-on-the-wall unit? – Daniel Griscom Dec 31 '16 at 13:08
  • Can you post a photo or diagram of the situation with the proposed heater location marked? – ThreePhaseEel Dec 31 '16 at 16:10

The circumstance is a persistent pinhole leak that sprays the wall wet for an extended period of time until the drywall becomes saturated and crumbles. And most people say "I would spot that immediately", but having seen a few water-heater leaks, real world, most people don't for weeks. And then take more time dealing with it.

Also, you would know it was urgent, but the next occupant may not.

Remember the scene in Breaking Bad where he ignores the leaky hot water heater until the floor rots out?

Honestly, I would use two strategies:

  • mount the hot water heater below the service panel. You don't want water near your service panel, but water doesn't flow uphill.

  • build a hardback false wall set on spacers several inches (like 3-1/2") out from the wall, so there's an intermediate gap. The false wall would stop short of the floor, put a drip pan under it. Water sprayed onto the false wall can only run down to its bottom then drip into the pan. (make sure the spacers stop before the bottom of the false wall so streams don't detour onto the spacers).

  • Plywood would be convenient to construct but it lacks fire resistance (which is important next to a water heater). Hardibacker or tile would be a better choice. I like the drip pan under the false wall face! – wallyk Dec 31 '16 at 18:09

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