Why is copper used for hot water pipes?

It won’t (unless that is the only 6 inches that can be seen by an inspector).

Normally, they want the entire run from the water meter to the hot water heater to be copper or other more modern piping type.

One important difference between copper pipes and plastic is that plastic pipes do not conduct electricity. In the old days it was assumed that if you earthed (grounded) anything to a copper pipe, it was earthed. You should no longer assume that as it is perfectly possible to have a system that is part copper and part plastic, The copper part might easily be isolated and not grounded at all.

In the UK, the latest code (since 10 years or so) requires that all plumbing fittings are connected to a wire bonded earth circuit.

[QUOTE=ZipperJJ]
What are the downsides of PEX?
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[QUOTE=friedo]
PEX requires specialized tools. You also don’t want to leave it exposed to sunlight. Other than that I can’t think of any big downsides to it.
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If you’re just starting out, all piping materials need specialized tools, but a plumber with more than a month’s experience will already have copper tubing cutters, reamers, soldering torch, PVC pipe cutters, PVC primer and cement, etc… The original style fittings for PEX do require special expansion tools, but there are newer “sharkbite” fittings that are DIY-friendly, requiring only a smooth square-cut end on the tubing, which is simply pushed into the fitting. They’re rather expensive, making them unlikely to be used by a professional plumber.

The sunlight issue is a big one for PEX - two to four weeks’ exposure to sun is said to completely deplete PEX’s resistance to chlorine, which can lead to a severely shortened lifespan before bursting.

Another problem is it can’t be recycled. Nearly 100% of copper pipe gets recycled, but so far, about all anyone’s figured out to do with old PEX is to pulverize it. So then what do you do with a pile of plastic sand? PEX is a thermoset plastic, so it can’t be chipped up and re-melted like vinyl or PVC.

[QUOTE=snowthx]
Are the waste water pipes also copper? Thx
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I’ve never seen copper drain lines in a house, but the materials do exist. AFAIK, San Francisco may still require copper drains in commercial buildings. It’s breathtakingly expensive.

With costs where they are the argument for copper over PEX is being settled. PEX has a long enough track record now that most plumbers are comfortable with using PEX over copper. CPVC is also an option but it’s certainly a crappier less reliable material.

Even in houses plumbed in PEX copper is still used for a lot of the manifolds and valving.

PEX can’t be exposed to UV, PEX is not rigid so needs to be secured more than copper, it also is impacted more by thermal expansion so it has to be secured in ways that allow for this. Rodents can and do chew on PEX so depending on location it might not be the best choice. PEX connections cause a lot of friction loss so if there needs to be a lot of joints you’d need to use larger diameter pipe which may not be practical.

My job is to supply water via wells or less frequently municipal supplies. I use HDPE, brass and copper for the most part.

In short copper was used because there wasn’t a better option. Copper is still used because it has the longest track record of being the best option. There are some things you can do with copper that you can’t with PEX.

If you have a better material to plumb houses with that won’t increase the cost we’ll hear it. Until then thermal loss isn’t a significant enough factor to change things. The change from copper to PEX is almost entirely based on the cost of material and installation. It’s a marginal reduction in thermal loss from copper.

You have galvanized steel pipes(plan on replacing them all someday) The inlet and outlets on the water heater are brass. You can not connect brass and galvanized pipes to each other(they corrode one another), they need to be 6 inches away as a dielectric break. Copper also shouldn’t be connected directly to galvanized but it doesn’t have to have a 6 inch gap, a dielectric union is sufficient.

When I had new copper water pipes put in my house , we had to keep the pipes in my house until it was time to install them . They would had been stolen if left outside. I don’t like PVC pipes , a plumber told me to be careful what I put down the drain b/c it could damage my PVC pipes. Everything is made out of crap today !

Copper on drains wasn’t all that uncommon in the past. For residential PVC and ABS are the most common. Commercial still uses cast iron which will include some copper for specific applications.

Copper and cast don’t burn so they are still required by fire code in many places.

Was what I heard correct: They never used aluminum because it can’t be soldered? Of course now, aluminum being linked to Alzheimer’s they wouldn’t dare use it.

This being GQ, do you have a cite for the link between Aluminum and Alzheimer’s? The only one I have heard of was discredited decades ago.

Yes, aluminum doesn’t lend itself to in-the-field installation or repairs.

I was going by Cecil’s first column (which was, I now realize, 1983), which had a closer connection between aluminum and Alzheimer’s, and never saw his follow-up column on the subject. But I remembered the column from 32 years ago and I avoid aluminum as much as possible, that should count for something (no, it doesn’t)! Actually that’s good news that the connection is not as harmful as I thought from the column (fingers crossed); thanks for passing that on.

Not as much as copper or other metals perhaps, but, then, it doesn’t PVC either. The latter is probably cheaper, though.
Aluminum wouldn’t work for outlets though, because of people’s custom to clean them with Drano. Sure, it dissolves most organic matter; but it dissolves aluminum just as quickly.

Thanks for the explanation. Yes, he did put on a dielectric union between the copper and steel just like the one in the picture.

In my guestimation based on 40 years of plumbing repairs for friends, family, and the (occasional !) paying customer on so-called PROFESSIONALLY installed plumbing failures : 5% have been related to copper, 15% have been related to CPVC, the rest (80%) have been related to PEX.

I’ll leave the statistical analysis to others, but it seems to me that this answers the OP’s question concerning the long term cost of plumbing materials.

Well I am going to offer the opposite opinion, we see hardly any problems with PEX, and copper is much more likely to burst due to freezing. When we do see frost damage in PEX plumbing it is almost always a brass elbow that bursts rather than the PEX itself. I think a lot of confusion comes from the fact that Poly-B, an earlier plastic piping product was a very bad product with high failure rate. Most water damage we see at work is caused by Poly-B plumbing from the late 80’s - early 90’s. It generates a lot of restoration work for me, and we always recommend homeowners replace as much of the Ploy-B as possible with PEX. The good news is it is often relatively easy to pull through new PEX with the old lines. None of the plumbers I have worked with have ever had a bad thing to say about PEX. It is cheap, really tough, and easy to work with. Fittings are crimped, its fast and the tools are pretty basic, cheap ones are about $30. Sharkbites are for quick repairs or temporarly capping off a line; most plumbers wont use the for anything permanent.

I’ve only seen PVC used in Ikea vanities, otherwise it is not used here in Western Canadian plumbing at all. PVC is pretty common for direct vented furnaces and water heater vents. Waste plumbing is almost exclusively ABS and the only advantages cast iron had over it was fire resistance and less sound transmission. Otherwise it is cheaper, more chemically inert, far easier to work with. It is a great product. Ill take the future thank you, modern materials are way better over all and the old materials are still available for the places where they are better.

If you want to insulate your hot water lines just install some foam sleeves from Home Depot.

When my house was being worked on someone mentioned to my parents that the waste pipe from the bathroom down the back wall to the drains was asbestos, does that seem likely?

I remember there was a large lump of lead channelling water from the toilet into that big waste pipe too. The water supply (which came from the street to the neighbour’s and then through the back of their house to the back of mine via lead pipe) was quickly replaced by tougher plastic stuff.

The rest of the house had stolen copper piping replaced with the plastic stuff, which for a newbie like me was great to work with, I felt like it was easily dumped and replaced if I made a mistake cutting it somewhere. But then as with cooking utensils, copper has a charm of it’s own and you feel you’ve done a better job when you’ve cut and fastened it into place.

Molten lead soaked into hemp gaskets is a traditional method for joining cast iron drain and waste pipes. It’s a huge pain in the ass. PVC just requires a hand saw and that stinky glue. Goes together in 30 seconds.

About copper, “old” housing, and prices.

I live in one of the largest urban housing projects in the country (now quite desirable and expensive) built originally with Federal support for WWII veterans. To this day, its ultimate worth to developers is limited by its lousy plumbing, and–although not plumbing, the same issue–that the electricity, without each apartment being rewired, to this day cannot handle AC loading.

I was told the reason for both is because it was built during the War, and with copper rationing they made the pipe wall diameters (too) thin, and couldn’t install sufficient wire for the amperage.

Does any of that make sense? Even if not for the rationing, is/was it as a possibility this was done to save money on copper?

Wrapping piping with asbestos was fairly common, Even on pipes that had no reasons to be insulated they’d put it on.

I haven’t seen asbestos pipe in a home. They made cement pipe with asbestos mixtures but that was larger diameters then you’d find in a home.

Yes there was a copper shortage and they did a lot of things to make due, that’s where aluminum wire came in, which has been quite a disaster. On houses they didn’t use aluminum they ran less circuits, they didn’t use smaller size wire to my knowledge.

On copper pipe there are multiple thicknesses, M, L and K are the most common. L is the standard. Cheap builders were it was/is allowed would use M which is thinner wall. M is intended for closed heating systems where corrosion is limited. If you use it for water supply it wears out much faster than L. K is thicker but it isn’t used at all in residential.