Copper lasts 30 to 40 years and stays clean inside. Polyethylene costs a fraction of it and lasts 10 to 20. But the real argument against poly is not lifespan, it is what can come through the pipe wall from contaminated ground, and that is a live issue in New Jersey.
This question comes up on almost every water service replacement, and it usually gets answered on price alone. Price matters, but it is not the whole picture. Here is the honest version.
Copper
Life: 30 to 40 years in our experience. Copper is the long answer. It does not build up gunk on the inside the way plastic can, and a copper service put in properly will outlast most of the people who paid for it.
The catch is the material cost. Copper typically runs 10 to 12 times what the equivalent poly costs. On a long run that is a serious number, and it is the single reason most people end up asking about poly at all.
Polyethylene
Life: 10 to 20 years, sometimes longer if you get lucky. Poly is considerably cheaper and it is genuinely easier to install, particularly where the line is being pulled through rather than trenched. Those are real advantages and we are not going to pretend otherwise.
It is more prone to breaking, and it degrades faster. Which is why a poly service that went in during a renovation twenty years ago is often the thing that failed and brought you to this page.
The part nobody mentions: contaminants can pass through plastic pipe
This is called permeation, and it is the strongest argument for copper. It is not a theory, and it is not something contractors invented to sell you the expensive option.
The EPA defines permeation as the passage of contaminants from outside the pipe, through the pipe wall, into the drinking water. In its issue paper on the subject, prepared with the American Water Works Association, the finding is blunt: pipes made of plastic were involved in 98 percent of reported permeation incidents, and no reported incidents of permeation through metal-based pipe were identified.
What gets through is petroleum. The contaminants most likely to permeate plastic are the lipophilic, non-polar ones, meaning diesel, gasoline and solvents. In one documented incident, benzene permeated a black polyethylene service line and reached a concentration more than 100 times the drinking water maximum contaminant level.
So the question is not really copper versus poly in the abstract. It is: what is in the ground your service line runs through? If there was ever a heating oil tank on the property, a gas station nearby, a spill, or any reason to think the soil has petroleum in it, plastic is the wrong pipe and the price difference stops being the deciding factor. We deal with contaminated ground often enough that this is a real question here, not a hypothetical. Our page on NJ Spill Fund water line connections covers what happens when a well or a supply is affected.
Some towns have already made the choice for you
A number of New Jersey municipalities and water utilities have restricted or banned polyethylene for water service lines, and more have moved that way in recent years. Which materials are permitted is set by your town or your water utility, not by a statewide rule, so it genuinely varies from one town to the next.
Check the specification before you choose, not after. A material your neighbor used ten years ago may not be accepted today, and finding that out at inspection is an expensive way to learn it. One call to the water utility settles it.
So which one
| Situation | What we would use |
|---|---|
| Any reason to suspect petroleum in the soil, past oil tank, nearby station, known spill | Copper. This is the one case where it is not a budget conversation. |
| Your town restricts or prohibits poly | Copper. The decision is already made. |
| Long run, clean ground, budget is the binding constraint | Poly is a legitimate choice. Go in knowing it is a 10 to 20 year pipe, not a 40 year one. |
| You intend to be in the house a long time and can carry the cost | Copper. Doing it twice costs more than doing it once. |
Common questions
Copper vs polyethylene water service line in NJ: which is better? Copper lasts longer, 30 to 40 years against 10 to 20 for poly, and it does not build up deposits inside. Poly is considerably cheaper, since copper material typically costs 10 to 12 times as much. The deciding factor is usually neither of those: plastic pipe can allow petroleum contaminants in the surrounding soil to permeate through the pipe wall into the water, which metal pipe does not, so if there is any reason to suspect contaminated ground, copper is the answer regardless of price.
How long does a water service line last? Copper commonly runs 30 to 40 years. Polyethylene is more like 10 to 20, sometimes longer. Both numbers move with soil conditions, water chemistry and how well the line was bedded when it went in.
Can contaminants really get through a plastic water pipe? Yes. The EPA issue paper on permeation and leaching, prepared with AWWA, reports that plastic pipes were involved in 98 percent of documented permeation incidents and that no incidents of permeation through metal pipe were identified. Diesel, gasoline and solvents are the contaminants most likely to do it.
Is polyethylene banned in New Jersey? Not statewide. Permitted materials are set by your municipality or water utility, and a number of them have restricted or prohibited poly for service lines. Ask your water utility what its specification allows before you pick a material.
How much does it cost to replace a water service line? Around $8,000 to $10,000 for a 200 foot service, varying with the material you choose and how hard the digging is. Every range we publish is on what this work costs.
Still not sure how this applies to your property? That is what a free on-site estimate is for. Call 862-268-2510 or tell us what is going on, and we will give you a straight answer, including when the answer is that you do not need us.
Sources
This is general information, not a recommendation for your specific property. Your water utility sets what materials are permitted at your address, and what is in your soil is a question worth answering before you choose a pipe. If you want somebody to look at it, that is a free on-site estimate, and the wider job is on our sewer and water line page.
A real job where we specified poly on a 500 foot run, and why: a 500 foot water line in Andover.