Water Heater Relief Discharge

Am I okay if my water heater relief discharge goes into a drip pan that can overflow, if needed, to the dirt crawlspace?

novice's opinion

(not a pro): I think the 'overflow' tube is actually a pressure relief tube. So, if the valve on the top pops, you'll get steam out of there and minimal actual liquid water. Discharging into an overflow pan won't do anything in that case.

If your water heater develops a leak, it won't be from that tube. I saw someone put their whole water heater into an overflow pan with a moisture-activated alarm and a valve that shut off the cold h2o supply to the heater in the event of a leak. If he hears hear the alarm, he might be able to drain the residual water through the drain valve (at the bottom) b4 the overflow pan is filled. If he doesn't hear the alarm, then at worst he'll get only a tank's worth of water damage.

Another note: some people say it's good to 'pop' the valve every year to test that it works. Others say not to, because it's a pain to get closed again. Check with someone who knows for sure b4 'testing' it. I haven't havd the guts to try it yet.

I'd say it depends on the soil in the crawl space. I install a water heater for my daughter awhile back and set it in a pan. Then while exploring how to best run the drain for the pan, I realized that her house is build on old river bed. So, I just ran the drain into the crawl space because you couldn't saturate that ground if you ran water in it for a month. Unless you have that type of soil, I'd suggest you run the pan overflow to the outside. When a PRV pops, it's just a small stream of water anyway, and if the tank goes south, they will leak but not suddenly fall apart. I suppose a moisture alarm in the pan wouldn't hurt, but I would lose sleep over not have one. Now, if the tank is over finished living space, you certainly will want the overflow to either go outside or into a drain.

its OK

the idea is to keep the water from the pressure valve from
flooding out your home........

you will probably NOTICE the water in the pan in either a few minutes or days....

on average people will notice the water pretty quickly if it is in
the living area or laundry room....

you will probably HEAR the water dripping into the pan


Its a pretty good set up the way it is and
its far better than the alternative.....of a major flood

and you really SHOULD NOT just pipe that pop off pipe
directly into the crawl space the you could really flood the crawl
indeifintely.......

I have seen the damage form this.....
and I was almost on the hook for the water damages it caused


the hot water from the heater can literally create a STEAM JUNGLE
affect in the crawl space if it goes on for a few weeks....... and this will
actually warp your ply-wood floors and the joists .......

you cant immagine anyone letting this pop off
for any length of time but it happens... quite often

if they cant see it happenning
right before their eyes, or hear the water running
its usually ignored

out of sight , out of mind...

My suggestion was not intended to imply that one should allow water to run indefinitely into the crawl space. The overflow from the PRV or leaky tank should be noticed and dealt with within a reasonably short time.

T&P

The safety valve is supposed to open at 200 degrees, long before it reaches the steam temperature, so it will be all water.

Your local code will answer the question. Some areas would not accept the overflow discharging into the drain pan. Some would.