Is there a good code-compliant way to vent the following exterior water heater (see attached drawing).

I thought this concept would work, but I am stuck trying to figure out a good way to vent.

The best I have is:

  1. out the shed-top, 45 to under rafter-tail, 45 up through rafter tail

  2. 90 inside enclosure to stucco wall, 90 up through rafter tail

Either of these ideas, i do not know if they are code compliant?

Any suggestions/help would be appreciated, thank you.

This is in the Central Valley California.


enter image description here


Revised site-plan drawing (to submit to city):

enter image description here


In the end, my initial drawings did not work out because of local building setbacks to the property line/fence (requiring a 5ft setback from the structure to the fence).

I had to redraw the plans. But it has now been approved, with the vent going straight-up and out.

enter image description here

  • 2
    If you're putting the water heater outside, would it be correct that snow and ice sliding off the roof is not a concern in your area?
    – Ecnerwal
    Sep 22, 2023 at 2:53
  • Forgot to add the location, but you are correct, I am in the Central Valley California.
    – farinspace
    Sep 22, 2023 at 4:37
  • 1
    why wouldn't you go with a heat pump hot water tank? Sep 22, 2023 at 8:01
  • I want to say heat pump hot water heaters, while very compact, operate from electric, I haven't exactly seen the breaker and power requirements but if the requirements are anything like a tankless, I would have to upgrade my small 100A panel
    – farinspace
    Sep 22, 2023 at 14:40
  • Heat pump water heaters are not particularly compact (they are storage tank heaters) and typically run on 25-30A or less (the required ampacity depends on the resistive backup heating element size; the heat pump itself typically only uses 5-10A, and you can get units with "smaller than usual" resistive backups where planned use is mostly heat pump mode.
    – Ecnerwal
    Oct 17, 2023 at 22:07

1 Answer 1


Straight up and out the enclosure roof, then continue straight up until the end is at least 2 feet above any obstruction within 10 feet (such as the higher part of the roof.) That may require bracing the pipe. It avoids poking any holes in your main roof, which I'd consider an advantage.

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