T&P Valve Discharge "CAN go UP"

So we all know that the code says that the Water Heater T&P Discharge pipe must go down to an approved point. Well… That is not always true.

Two cities in CA, San Jose and Palo Alto have developed an alternative method for water heaters installed in a basement or in locations where it is not possible for the T&P relief to achieve gravity drainage, a special provision for drainage is allowed…

In this case the T&P Valve runs out to a Tee turned vertical the top running up and out to an approved discharge point The bottom of the Tee then runs out to a 90 degree elbow and down to a 3/4" to 1/8" reducer. From there a drip coil of 1/8" copper tubing is installed with the far end crimped down and discharged to a pan under the water heater. If on a dirt floor a 3" pad is required.

Per the AHJ, this provides a safe method of discharge without flooding a non-drained basement. The purpose of the coil is to allow seepage from a failing valve or if it is manually activated to prevent.

While on the surface this seems easy enough we still find trades having difficulty installing them.

The first image is a shot of a water heater I recently inspected. From a distance it looks ok. But in the second image the issue becomes obvious. The city drawing assumes the TPRV is on top of the water heater. In this case the trade used the side mounted T&P valve point. So they turned the T&P upwards and completed the install. In this case a portion of any seepage or manual discharge will remain at the valve and potentially cause a failure of the valve to possibly discharge. (In our area we have very hard water) What should have happened is the discharge going down as usual a couple of inches and then 90 degrees out to the Tee and the install completed as intended. I apologize for the second image being sideways I can not get it to post in the right orientation.

My reason for posting this is that I recently had a client purchasing a home in another city with a basement installed water heater. (FYI they don’t have many basements in this city) The seller had just installed a new water heater and the city inspector was there and he was not so kindly dressing down the plumber for trying to run the T&P on an upward slant. Needless to say the plumber was embarrassed, the seller was not happy and the young couple buying their first house was tuning pale. Not being shy I introduced myself to the city inspector and asked if I could show him an approved variance from another city. I carry a copy of San Jose’s approved drawing. Well after making a call to his boss he returned and told the plumber to install in compliance with the drawing and he would come back and sign-off. Needless to say everyone was happy with the outcome. As Home Inspectors we go above and beyond for our clients. This was one opportunity for me. I hope one day this may help one of you do the same because I shared.

I would like to hear from other inspectors out there that have different approved installs in their area.

Thanks for taking the time to read.


Interesting thanks for the post… Roy

Well that is strange and different. Interesting that they are concerned with T&P discharge water not winding up in the basement but not water from a ruptured tank which IMO is a lot more common. Probably to accommodate all of the annual valve testing that everyone is so diligent about doing (self included).

It’s good that you were able to offer up a viable solution where the plumber and AHJ were stuck for one.

Thanks, could you share the drawing you showed them?

Basements are very rare in Los Angeles area, and almost non-existent in the San Fernando Valley. The very few times I have seen a water heater in a basement, the water heater is usually equipped with a Watts 210 gas shut-off valve.

Hi Everyone,

Thanks for the comments. I am attaching a Jpg of the drawing from the city. Sorry it is not the best was a copy of a copy… and I am still trying to get an original in electronic format. We do not see a lot of basements except in older homes. However there are enough in these two cites to justify the variance.

P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature-relief valve or combination valve shall:

  1. Not have valves or tee fittings.

Commentary: What would be perceived as a fix would actually be creating a very serious hazard. Because the installation of valves or tees in the relief valve would only invite someone to close the valve (thus blocking the flow) or connect another drain line to the discharge pipe (creating another hazard), their installation is prohibited.

Contact the actual valve manufacturer…let them know this is what being approved.