Thread: Grounding Water Pipe Question

I am in the process of purchasing an older home built in 1918 that needs some work. I had an inspector come out and take a look and he declared I need to have the water pipe grounded. I am just curious as to what that entails to? What does it mean to have a water pipe grounded? I've never heard of such a thing.

I will have an electrician come out and actually do the grounding, but I'm curious about the process and just want more information, so I know ahead of time what I'm getting in to.

Thank you.

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He could be referring to more than 1 condition. Possibly a jumper across a water heater (etc), or a ground from the water main, where an existing ground is connected to an earthen ground (rod), etc.

What were his exact words? Did he supply you with any photos?

Originally Posted by Matthew Wolfe

I am in the process of purchasing an older home built in 1918 that needs some work. I had an inspector come out and take a look and he declared I need to have the water pipe grounded. I am just curious as to what that entails to? What does it mean to have a water pipe grounded? I've never heard of such a thing.

I will have an electrician come out and actually do the grounding, but I'm curious about the process and just want more information, so I know ahead of time what I'm getting in to.

Thank you.

What material is the water pipe made of?

There may be a mis-use of terminology here. I'm going to bet that your inspector was, or should have been, referring to "bonding." In any event it's a rather simple correction. The problem can be in getting a contractor who understands grounding and bonding.

Originally Posted by Matthew Wolfe

I am in the process of purchasing an older home built in 1918 that needs some work. I had an inspector come out and take a look and he declared I need to have the water pipe grounded. I am just curious as to what that entails to? What does it mean to have a water pipe grounded? I've never heard of such a thing.

I will have an electrician come out and actually do the grounding, but I'm curious about the process and just want more information, so I know ahead of time what I'm getting in to.

Thank you.

According to the 2011 NEC, though, there should be no grounding whatsoever to the plumbing system of a house as was done in the old days.

Originally Posted by Harry Turner

According to the 2011 NEC, though, there should be no grounding whatsoever to the plumbing system of a house as was done in the old days.

Interesting info...can you point me to that code section? I don't have a 2011 code book yet.

Originally Posted by Harry Turner

According to the 2011 NEC, though, there should be no grounding whatsoever to the plumbing system of a house as was done in the old days.

Please provide the Article that pertains to this very drastic change. This has not been covered in the Code update articles in the trade magazines.

Originally Posted by Harry Turner

According to the 2011 NEC, though, there should be no grounding whatsoever to the plumbing system of a house as was done in the old days.

As Jim was indicating, I suspect there is a mis-reading in what the NEC says ... please provide the code which states that.

It is unclear if you are referring to an underground conductive metallic water service which if in contact with the earth for sufficient distance and present must be incorporated as an electrode into the grounding electrode system, and which generally must be supplemented with an additional electrode, made or otherwise; or the bonding of conductive metallic piping system or portion thereof which may become electrified; or the bonding of a metallic piping system over interuptions.

It is important to note that older homes, especially of that vintage may have been supplied with a LEAD water service, or utilized other forms of supply piping not able to function as an electrode and/or which may or may not have "sufficient earth contact", or may have been replaced with other materials.

Premisis electrical systems of that vintage would not have been of the type which provided an equipment grounding conductor with the branch wiring, or if provided, not a sufficient grounding path. "Polarized" wiring was also not of the "vintage" (receptacles which allowed appliances to be plugged in and operated therefore with their wiring "reversed" such as portable lamps, switching other than the "hot" conductor was common in the past.

"Bootleg grounds" or "floating grounds" (floating interconnections between electrical circuit devices and the premisis metalic piping systems, e.g. potable plumbing pipes) was also common in the past as older 2-wire type premisis wiring systems were modified to incorporate "grounding type" receptacles, appliances, such as garbage disposals, etc., and even permitted up through the early 80s code cycles. Folks would use "three-blade/prong" adapters to plug in three prong appliance cords to 2-bladed receptacles, etc.

Services need their grounded ("neutral", "center tap") conductors referenced at the service entrance, this is in part to protect the premisis wiring from (not direct) lightning along the utility equipment and over voltages during the momentary period before the utility system protections "kick in". It is not a lightning protection system, and will not protect against a direct lightning strike. Generally the next "upstream" "ground" (electrode) connection is at the last utility transformer which supplies power to your area.

Areas of the NEC saw significant re-writes and corrections in the 2008 (incomplete and not entirely comprehensive) and 2011 (more complete and comprehensive) code cycles relative to grounding and bonding.

Many modern plumbing faucets, mixing valves, etc. incorporate materials (plastic, ceramic, cartridges, seats, etc.) which interupt or provide resistance to the "path" and require a bonding around same, some are made of non-conductive or poorly conductive metal alloys.

It is a good thing that you are having an electrical contractor review your entire electrical system for safety. An early 20th century home may have had a host of modifications and changes over the years, and the materials present may not be sufficient, installed correctly, maintained, or in a condition or state that can be relied upon for safety, nearly 90 years later.

Electrical usage patterns have changed significantly in the modern "age", calculations, temperature ratings, etc. should be considered, and any projects you might be considering regarding your use of the home and your own plans (adding appliances, equipment, etc.).

This topic should have been in the "questions from homeowners, homebuyers, and DIY" area. You may find it has been relocated to that forum area when you return later.

Just thought i would save any confusion with the water supply grounding. This is copied directly word for word from the NEC 2011 book. no changes, still allowed




250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe.

A metal underground
water pipe in direct contact with the earth for 3.0 m (10 ft) or
more (including any metal well casing bonded to the pipe) and
electrically continuous (or made electrically continuous by
bonding around insulating joints or insulating pipe) to the
points of connection of the grounding electrode conductor and

the bonding conductor(s) or jumper(s), if installed.