Water heater relief valve question

If the water heater is located in the crawlspace does it need the Relief valve extension?

I’m not sure what your asking.

Got Pic?

Meaning extending the TPR tube to discharge outdoors???

The water heater for this home was located in the crawl space under the home…in this instance would the TPR extension be needed?

I rarely see crawls, so I am not well versed on them, but, IMHO, yes it still needs to exit the structure to an observable location.

I’m sure someone with more crawl experience will chime in soon…

504.6 Requirements for discharge piping.
The discharge
piping serving a pressure relief valve, temperature relief valve
or combination thereof shall:

  1. Not be directly connected to the drainage system.
  2. Discharge through an air gap located in the same room
    as the water heater.
  3. Not be smaller than the diameter of the outlet of the
    valve served and shall discharge full size to the air gap.
  4. Serve a single relief device and shall not connect to piping
    serving any other relief device or equipment.
  5. Discharge to the floor, to an indirect waste receptor or
    to the outdoors. Where discharging to the outdoors in
    areas subject to freezing, discharge piping shall be first
    piped to an indirect waste receptor through an air gap
    located in a conditioned area.
  6. Discharge in a manner that does not cause personal
    injury or structural damage.
    7. Discharge to a termination point that is readily observable
    by the building occupants.
  7. Not be trapped.
  8. Be installed so as to flow by gravity.
  9. Not terminate more than 6 inches (152 mm) above the
    floor or waste receptor.
  10. Not have a threaded connection at the end of such piping

don’t know the requirement or restrictions, but from a common sense point of view, it would only make sense if it was visible somewhere. Who would notice it leaking the crawlspace?

Thanks guys


One would never want sources of water into the crawl space. A TPR valve emptying into the crawl would be no different than a plumbing leak into the crawl.

I have a report I am working on right now where the TPR pipe goes straight into the crawlspace from above.DSC03823 [320x200].JPG

If it’s in a walk in crawlspace, it must be a readily accessible area. I personally don’t call for an extension to the exterior in that case. If a water heater is discharging into a regular crawl space, from above, I call that out.

Wouldn"t a walk in crawl space be called a basement?

I think one of the main differences to me is a walk in ‘crawlspace’ has a dirt floor and a poured concrete perimeter foundation with wood framed walls. Ussually only a relatively small portion is high enough to actually walk through.
Like this:


Sometimes I’ll run across one that I’m not sure what to call it.

My head hurts.