Q:

Best option for DIY water heater platform

16 year old gas water heater started leaking, so time to replace!  The old water heater was on a 3-legged stand, and the stand is permanently embedded in to a concrete blob on top of the concrete garage floor.   My quick fix, wife needs hot water now, was to cut down the stand and build a 2x6/plywood stand on top of the old legs.   Since wood is susceptible to water and fire, I thought this would be a temporary solution.

Is my plywood base actually okay, or should I consider replacing it immediately?
What are some options for improving the situation?   My only thought is to jack-hammer the old cement blob, and create a new square cement blob since garage floor is not perfectly level
How important is it that the water heater be perfectly level?

A:

I am disappointed that you cut down the old stand as it would have been acceptable as a base for a new platform. The reason the old stand was raised (as your new platform should also be) was to keep the burner elevated.
The burner is a source of ignition for flammable vapors that could be potentially present in utility areas or other low lying areas; garages, basements. In garages, gasoline or other flammable spirits are often stored, as well as vehicles with gasoline engines. Vapors from leaks or from handling are heavier than air, ergo the raised platform for the ignition source.
Some new water heaters are equipped with features that help prevent ignition of vapors, but it is still prudent to elevate and is very likely required by code, check with your local code enforcement authority.
If I were considering a wood platform, I would staple a sheet of waterproof roofing paper over the plywood top, then place a sheet of 1/2" cement board (like tile backer board/wonderboard) over that to set the heater on.

