TPR Valve Discharge pipe

Good Afternoon,

Been coming across several TPR discharge pipes that are very close, if not touching, the bottom of a water heater drip pan. What is the minimum distance from the bottom of the drip pan? Should’t there be some air gap? I understand the 6 inch rule for discharging to a waste receptacle but how close can the pipe be to the floor or drip pan?



Not good but I would say should be 6 inches but not make a big deal about it .

What have you been saying with the several you have seen

I would have in the report that the TPR discharge pipe should be approximately 6" off the ground. I would verbally mention to the buyer that it is a simple fix requiring simple tools.

Thanks Roy!

I have been telling the homeowner that the pipe needs to be cut to create an air gap and that the distance can be no bigger that 6 inches. The fact that I have seen this on several new homes and I couldn’t find anything in the Florida Building code that specified any change in policy, I figures I would ask the InterNACHI community for their thoughts.

Minimum 3/4 inch
Maximum 6 inches

Thanks Jeff…where is the 3/4 inch minimum written?

3/4 " is minimum size of the discharge pipe

And What do you do when the tank has a 1/2 pipe on a 1/2 tpr

Exactly. So logic dictates that the air gap should also be no smaller than the discharge pipe size.

not be smaller than the diameter of the outlet of the valve it serves (usually no smaller than 3/4").

Be sure to note in this (old, so may no longer apply) link that the codes referenced are for California and with EXTERIOR discharge points (6in to 24in).

This is the code in Wisconsin. The outlet of the discharge pipe shall terminate within 6" over the floor or receptor, but not less than a distance equal to twice the diameter of the outlet pipe. The outlet of the discharge pipe may not be threaded.