Do Manufactured Homes require a specially certified water heater?

Well... yes and no but first, a story..

We performed an inspection a couple of years back for a client buying a manufactured home. There was a brand new replacement (i.e., not the original) water heater installed (with some fixable defects - missing thermal expansion tank, missing sediment trap, etc.). Well, two years later, our prior client is now selling the home and the buyer had a property inspection done. After seeing the report, out prior client contacted us, very concerned and wondering if we missed something on our inspection two years ago. The new inspector flagged his water heater as a major safety defect because it was not specifically designed (and placarded) for use in manufactured housing. Was that inspector right to call that out? We shall see...

Yes, manufactured homes require special water heaters that are specifically certified and labeled for manufactured housing.

But, we're in California and, well, things are sometimes a little nuanced... If the manufactured home is new, well then, that specially certified water heater is necessary (and likely already installed).

But what about a replacement water heater in a manufactured home? Let's say you are buying a manufactured home that does not have the original water heater or you already own a manufactured home and need to replace the water heater - will you need to get a "specially certified and labeled water heater for manufactured housing"?

Short answer is: NO - a replacement water heater that is specially certified and labeled for manufactured housing is not required.

Turns out, California has addressed this specific topic in the Health and Safety Code (specifically, HSC 18031.7). Here's the salient part:

"18031.7. (a) Nothing in this part shall prohibit the replacement of water heaters in manufactured homes or mobile homes with fuel-gas-burning water heaters not specifically listed for use in a manufactured home.."

Did you get that? "Nothing shall prohibit replacement... with water heaters not specifically listed for use in a manufactured home."

Legaleze is tough, I get it, but what it is essentially saying is that it is OK to replace a water heater in a manufactured home with a residential-grade water heater that is not specifically listed for use in manufactured homes.

Now, of course there are other requirements such as seismic bracing, fuel source labeling, etc. but these are generally standard with commercially-sold water heaters that are being installed by a licensed contractor. But the point is, if you are buying a manufactured home with a replacement water heater (or replacing a water heater in your manufactured home) and there is not a label on the water heater saying it is specifically listed for use in a manufactured home", you need not worry.

In closing, allow me to briefly revisit the story we began this post with. As I mentioned, the water heater that we inspected 2 years ago was brand new at the time. We found defects with the installation (missing thermal expansion tank, missing sediment trap, etc.) and I can tell you with near certainty that the water heater was not installed by a licensed professional. How do I know this? Well, any good licensed professional (plumber in this case) would have installed both a thermal expansion tank and a sediment trap on the gas line because it was a code requirement to do so at the time.

So, the last point is this: Use licensed professionals whenever possible! They generally save you money in the long run (by doing it right and to code). This is especially true if you are having electrical or plumbing (water or gas) work done, ALWAYS, ALWAYS, ALWAYS use licensed pros!