The outdoor faucet was turned on today(45 degrees), shortly after we discovered a leak in the house. We're not sure if the faucet broke or the pipe fractured/burst. After pulling back the drywall we noticed that there is a copper wire in conduit bracketed to the water pipe at the faucet. Would it be safe to try to find the leak by turning the water back on, if we turn off the electricity?

I was under the impression that grounding to a water pipe occurred outside of the house, is that incorrect?

  • The only place I am familiar with grounding to a water faucet outside the house is when retrofitted with Cable service. It is assumed all water pipes are grounded.
    – SDsolar
    Commented Apr 4, 2017 at 18:28
  • In the U.S. the water pipe if metallic is supposed to be bonded within 5' of entry if metallic, I have seen cable systems grounded to metal water pipes on older homes so I would think redgrittybrick probably has a good answer as that is not standard in the U.S.
    – Ed Beal
    Commented Jul 17, 2018 at 14:14

3 Answers 3


In the UK, current regulations require all metallic pipework be connected electrically, this is called equipotential bonding.

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(images from electrician2hire)

By law, the connections must be labelled (typically with an embossed metal label)

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I believe current regulations require this equipotential bonding in every room that has metal pipework. This helps guard against loss of earth bonding when a small section of copper pipe in between locations is replaced by plastic pipe. The clamps must be in a place where they can be inspected - which rules out hiding them under the floor or behind plasterboard (drywall.)

  • What if all of the copper pipes in your bathroom are in places that cannot be inspected? Do you need to actually add an inspection place behind a removable tile or something like that, just for the bonding? (I’m not in the UK, just curious.) Commented Dec 27, 2013 at 16:04
  • @Christopher: I'm not an electrician and a copy of the relevant regulations costs £100 - and probably needs training to interpret correctly. From what I have read, if the supplementary bonding cannot be inspected, it must be tested electrically (<0.05 ohms) or result in a a class 2 notice on an inspection. So far as I know, most UK homes only get an electrical inspection after major electrical work. Also, I believe that if all circuits have RCD protection, supplementary bonding may be omitted. Commented Dec 27, 2013 at 21:05

It sounds like you've found a ground conductor. This would be a single conductor, usually a stranded wire made of copper or aluminum, clamped to the pipe. May or may not be in conduit. If you are able to follow the wire you may find it is used to bridge an electrical discontinuity in the plumbing (you'd see this across your main water meter) or to carry a ground connection to another piece of equipment (such as a telephone termination box).

For providing ground to your main service panel, the panel is usually connected to the water supply line if that pipe is metal. This is typically done inside the house, particularly on older houses. If your water supply line is plastic, you will have grounding via other means such as ground spikes driven down either outside or through your basement floor.

There's no likely danger from getting a ground conductor a little wet once or twice. If you've located the leak on a pipe and are just really narrowing down the exact location, leave the electricity on as long as you don't expect water to reach any electrical parts that carry a current - switches, outlets, lights, etc. You can touch a ground conductor, wet or dry, safely as long as you're not also touching a current-carrying conductor. You should NEVER be touching a live current-carrying conductor because you're often touching a ground (light housings, bathtubs, flooring), because current seeks ground, and because if the path to ground leads a lot of current through your body you will have a very bad day.

If I had a rough idea where the leak was, and didn't think there was serious risk of water leaking into or spraying a live electrical part, I'd probably leave the electricity on. Lower chance of banging into or tripping over something, which is good.

If you're not sure, get a non-contact voltage tester and you can check if there's live wiring near the pipe.


This is so totally wrong on all levels. I don't know whom ever thought up a code or standard that it is a good idea to ground the electrical panel to the cold water pipe in the building. But that is a very good way to electrocute people. The electric panel common or ground should always be connected to a copper stake driven into earth ground. What's the diff you say? Big. If you run the electric panel ground to a water pipe then you are using the copper water pipe as a path to earth ground. People touch water pipes! Take showers. As copper pipes age, the solder between the joints ages, corrodes, becomes much more resistive to the flow of current. On the other hand, the water flowing through the pipe with its chlorine content and acid rain content is a fair electrolyte. So, now put a person under the shower head, standing on earth ground, with the water flowing over him, and he becomes a parallel path to earth ground. In our development, we had a resident complain that he was getting electric shocks while taking showers. We found an Air Handler green ground connected the cold water pipe of the water heater just below it. We measured 12V AC to earth ground from the water pipe. That is enough to get your attention. Had lightning struck the compressor on the roof, that would have really gotten his attention. Never ever connect an appliance green ground to a water pipe. If you need a better ground, run a heavier green wire back to the common on the electric panel. In an apartment environment, the electrical inspector should assure that all commons in the electric panels in the apartments, are tied to an independent building ground stake hammered into earth ground, and not to the water supply.

  • 2
    You have this arse-backwards dude. You need to have the pipework bonded to the mains earthing system, that way your dishwasher cannot inadvertently dump full mains voltage on the cold water pipe system due to an internal fault and leave you with shocking results that way. (Not that you do not need an earthing electrode besides the water pipe that is, because you do.) Commented Jul 17, 2018 at 3:39
  • I agree for many years the pipe system was the only grounding device the requirement requires the pipe to be in contact with earth for 10 feet.
    – Ed Beal
    Commented Jul 17, 2018 at 14:17

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