California homeowner says rain-exposed water heater was meant for indoors, leaving warranty void

"Don't build an enclosure around it, it's still outside."

A California homeowner said a newly installed tankless water heater failed after being exposed to rain and then lost warranty protection because it was supposedly designed for indoor use only.

What happened

The issue came to light on Reddit’s r/Homeowners forum, where a Los Angeles-area homeowner said rain damage knocked out the board on a tankless water heater placed outdoors by a local plumber.

According to the post, the homeowner wrote, “My board on my tankless went out after the most recent rain.”

After a technician inspected the unit, the homeowner said they were told the larger problem was that the model was not meant to be installed outside. The poster said the tech explained that “my tank is an indoor and should not be installed outside. Because of that, my warranty is void.”

With warranty coverage apparently off the table, the question became how to fix the situation. The plumber reportedly offered to repair the system and “build a housing around the water heater,” but the homeowner questioned whether a full replacement would be more appropriate.

The poster asked, “Is it acceptable for me to ask him to change out the water heater? Clearly, that would be thousands of dollars that he would have to swallow, and I doubt he'll want to do that. What should I do when he refuses?”

Commenters noted that an outdoor installation is not necessarily improper and asked who selected the unit. The homeowner replied that the plumber had chosen it, writing, “He selected the unit for me but had me purchase [it] for ‘warranty purposes.’”

The local climate also seemed to factor into the decision. In response to concerns about outdoor plumbing, the homeowner said, “Los Angeles a few miles inland. Got our own slew of issues but frost's not one.”

The homeowner later said they had agreed to the outdoor setup because the plumber did not explain that it was an indoor-only model. They added, “He didn't explain it was an indoor unit. I live in Los Angeles and plenty of tankless are outdoors. The last place I rented before buying had an outdoor tankless. From my understanding there are tankless that are made for outdoor use. I assumed that is what he had me get, so yes I agreed for him to install it outside.”

Advice in the thread largely centered on replacing the incorrect unit instead of trying to protect it with an enclosure. One commenter suggested an “incredibly obvious compromise…You purchase a unit meant to be outdoors and he installs it for free.”

Another commenter was more blunt: “Don't build an enclosure around it, it's still outside.”

Where can I learn more?

Water heater disputes can become complicated when installation errors and warranty questions overlap.

• One homeowner won a replacement after a leaking water heater was initially denied under warranty.

• After a second unit leaked, homeowners said the warranty should apply to the repeated failure.

• A homeowner's gas unit kept shutting off until the warranty helpline flagged possible venting problems.