A couple of education questions

I just have a couple of education questions.

  1. When looking at the TPR installed on my hot water heater, I noticed the drain is a copper pipe, soldered to a threaded fitting and then screwed into the TPR. Standard 15 in the 25 Standards section says that a TPR discharge pipe should not have a threaded end. Is my situation ok because it is a pipe soldered to a fitting? Is the standard stating that the pipe shouldn’t be something like threaded gas pipe or something similar? Lastly, would a PVC pipe glued into a fitting, and then threaded into the TPR be allowed?

  2. When describing the location of the main water shut-off valve, I understand describing the shut-off in the house, after the water meter. My house also has the metal cap in the yard (near the curb) that you need the four-prong tool to turn the water on and off with. Is that shut-off strictly for the city to use? Do you describe the location of this shut-off in your reports?

Thanks for your help

  1. The discharging end is not to be threaded so as to avoid anyone from capping off the end incase of water dripping like when a valve begins to fail or discharge. Can you say “BOOM”?

  2. We generally don’t have the exterior shutoffs here in Minnesota, so my experience for other areas is… report the location of the “City and Plumbing Professional” shutoff as a reference of location for emergency use, but the primary shutoff for the homeowner is the one located in the home for their use!

Thanks for your quick reply.

  1. That makes way more sense when you say “discharge end”. My brain latched onto the idea that the pipe shouldn’t be threaded at all which confused me even more on how to attach a threaded TPR valve to an un-threaded pipe.

  2. That a good way to describe this shutoff valve, especially since it usually requires a specialty tool turn the water on/off.

Thanks for your help.

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Enjoy the music :cowboy_hat_face:


Jeremy The cap you were referring to in the yard is called a B box or Buffalo box. It’s a long piece of pipe with a saddle that sits on the corporation cock. Generally plumbers or utility workers will have a key to turn it off definitely don’t want to mention this as a shut off valve for the house as there is usually a ball valve or gate valve located where the water main enters the residence. In colder climates where water mains are installed below the frost line we will see Buffalo boxes. The water meter is located inside of the residence and should have a ball valve or gate valve on either side of the water meter. These are the valves you will want to mention in your report as the main water valves.

Surprisingly, in some of the small towns where I inspect, the houses do not have dedicated shutoff valves inside. The owners are expected to buy one of the specialized shutoff tools at the hardware store. That tool is used to shut off water at the meter.

FYI, PVC should not be used for the TPR discharge piping. CPVC is ok.

That’s crazy. Those keys are about 6’ long and cost over $50. A ball valve can be bought for under $15.

Thanks for all of your replies! I have heard that the city where I live really doesn’t want homeowners to use the outdoor shutoff valve or B-box (thanks Martin!!!). I actually had my indoor shutoff valve fail and without knowing where the B-box valve was, I would have had a geyser in my house for a few hours, until a plumber could get to my house. So, in my case it was good that I knew where it is located and how to operate it. I was really just making sure that it is not a bad idea to report on the outdoor valve if I do find it.

Thanks, I didn’t think about the super hot water that would be coming out . I’m sure PVC would melt or deform pretty easily.

Exactly why I place it in the “Informational” category of my Report!

Because, assuming the WH was actually functioning as intended, it would be super heated STEAM if the valve failed to open from temperature or pressure! If the WH was operating and the valve failed, by prematurely opening, it would be 210f hot water (or cooler).