Are there? It seems like plastics are shaping up to be the modern day lead.

Lead roofing tends to get recycled into bullets in time of war, but those roofs that don't, are typically there forever (400+ years) and never leak. Some plastics are UV resistant due to additives but even copper struggles to compete with lead as a roofing material. You only need to look back to the 1970s to find PEX water piping and the disaster/flooding it can cause due to age.

Are you thinking of polybutylene pipe, rather than Pex (cross-linked polyethylene)?

> Lead roofing tends to get recycled into bullets in time of war

That's interesting - I've read that there are a lot of castles and stately houses whose demise started from the owners selling off the lead roof, but I never understood why it would be so valuable that you'd destroy the building for it. Is that why?

Quite a number of British monastic churches and castles had their roofs sold off by Henry VIII, who was fully intending to destroy the building.

Using McMaster-Carr as a benchmark, lead sheet is a bit more expensive than the same size and thickness of 316 stainless sheet. One of these is extremely toxic and the other is pretty much harmless. (Also, 316 stainless won’t magically corrode if there’s condensation on it, and the Internet suggests this is a problem with lead.)

Sure, lead can be molded into place with traditional techniques if you can find a competent roofer with a sufficiently minimal desire for self-preservation. But modern standing seam roofs work pretty well.

Hopefully you don't have a fire....See: Notre Dame

Those don’t seem like comparables though. Lead is just one (or arguably a handful of) compounds, while there are at least dozens of species of plastic.

I highly doubt it. They don't seem to be perfect, but they clearly aren't anywhere near as toxic as lead.

Plastics for potable water tend to be copper lined where I live, not sure what is used elsewhere.

I've never heard of copper-lined PEX, can you tell me more?

I think op may be referring to 'barrier pipe', which is a plastic -copper-plastic sandwich, which is designed to keep out pollutants which can diffuse through the plastic - eg. Diesel oil.

If you don't use it for underground water pipes in cities, you'll normally get complaints from homeowners about 'chemical smelling' water, particularly first thing in the morning when water has been sitting stationary in pipes all night.

oh dear i forgot that plastics are permeable to petrochemicals lile paper is to water

There is a test for plastics where they weigh a block of plastic then soak it in water and weigh it again. For some plastics the gain in weight can be a few percent.

That's like saying "metal is strong". There are huge differences among different plastics.

Well, there are < 100 metals but thousands of varieties of plastic?

Not thousands, certainly not in common use. But yes there are many, and they have very different properties from one another, including permeability.

Barrier PEX (often referred to as PEX-Al-PEX) uses a layer of aluminum, not copper. A far more common type of barrier PEX uses a low-permeability polymer coating.

Oooooohhhh.. That make sense. Today I learned.

I still have a length of it in storage but I don't know the brand by heart. It was pretty expensive stuff and it needed weird fittings, which were also expensive, the inner liner was blue, that much I do recall. In the end I mostly regretted going for plastic, I'd probably use regular copper pipe and crimp fittings again, less hassle and I'm just more familiar with it.

Do you mean PEX-Al-PEX? It’s mostly obsolete now, in favor of “oxygen barrier” PEX. The latter is generally approved for potable use, but there’s no reason to use it. It’s intended for closed-loop heating or cooling systems that contain non-stainless iron alloys, and the idea is that any oxygen initially in the water will be rapidly depleted, and deoxygenated water is not corrosive.

Probably alupex "meerlagenbuis"? Comparing it to copper it seems to be much more affordable per meter. I worked mostly with copper in the past, but did some work with alupex on my brother's house a couple of years ago. It's much more convenient and affordable than copper!

I recently fell in love with copper pipes. So many advantages, so easy to work with. Quick and nearly fool-proof.

I tried introducing some stainless fixtures and did not have a good time with it.

I'm not a pro by any means but I do all of my own plumbing and gas work in my house. Haven't had one issue out of iron gas pipe or copper water lines. I was actually planning a pex install/replacement, and I have worked with it in my camper, but I changed my mind after doing some more work with copper recently (replaced water pressure regulator). Waaaaay cheaper than messing with pex.

People often go to Pex because it's way cheaper than copper. I use copper because the rest of my house supply is copper, soldering pipe is a skill that I have and enjoy using, there's a slight anti-microbial action from copper, and I trust it to last longer than I have years left around. I sure don't do it because it's cheaper, though.

I know some plumbers recommend Pex because it fails catastrophically -- if you run a nail through a pipe you'll know it -- whereas copper can have pinhole leaks which will slowly grow mold all over the inside of your wall without you noticing.

Straight new install of PEX might be cheaper but I can reuse copper fittings and they cost nearly nothing. Same with the runs of pipe...I can reuse copper without losing length. Just easier to deal with for maintenance.

I had a house where a brand new copper line corroded and started leaking 2 years from installation, and I don't mean at joints or anything, I mean the local water just ate right through the wall of the pipe. I switched to Pex and was fairly happy with it.

I never did do the research to figure out what was up with the water, but similarly, when I tried inventing my own sump-pump sensor by dipping copper wire into the sump well, it ate the copper wires apart in 3 days. I tried again with stainless rods and discovered that there was about .05 Volt per inch deep I put the sensor, i.e. the stainless rod near the top of the well would be about 2V higher (or lower, don't recall) than the stainless rod that ran to the bottom. Made it kind of annoying to design the circuit.

Looked in to this seriously for a product some years back. Captured ping pong ball floating on the surface of the water hitting a physical limit switch is the way to go. Otherwise ultrasound.

Convenient point for PEX: If copper pipes aren't properly grounded they'll tend to develop pinhole leaks within that timeframe.

Due to galvanic corrosion / electrolysis?

I'm not a plumber, that's what someone told me once a long time ago. But googling some more, systemic pinhole leakage can also depend on several factors like water cleanliness and pH, with some counties finding grounding doesn't cause pinholing and others finding it does.

The subject may be more complicated than my single sentence can capture.

I assume you have a well, not city water? Utilities generally try to adjust their water to be non-corrosive to copper.

If I used well water or had another non-city source, I would do my best to keep copper out of the plumbing and I would minimize brass as well. Stainless steel and plastic, please.

I assume the copper wire was designed as a simple resistive switch? That will cause electrolysis and corrosion. There's an improved design that involves measuring capacitance, which also uses less power. I have a commercial sump pump monitor that works this way.

Yep, but in the end I was able to switch by monitoring the voltage generated by the water on the stainless rods, using a microcontroller. Worked great for a few years until I moved out. Haven't had a sump pump since. (good riddance)

Stainless and copper do not mix. See galvanic corrosion.

Stainless steel is just fine in a copper system if it’s not electrically connected to the copper. Even if it is, you are unlikely to have problems unless the wetted area of the stainless steel is comparable to or larger than the copper, in which case you may accelerate corrosion of the copper.

You won’t have the problems you would have with galvanized steel. Copper ions leached out of a copper pipe will react with zinc and non-stainless steel and can very quickly degrade under some conditions even without electrical contact. Stainless steel, not so much.

(Don’t let rainwater that came from a copper gutter or that ran over treated wood hit a galvanized steel flashing. Really, just don’t use galvanized steel flashings at all.)

Stainless in (or near) contact with copper with moisture between them forms a battery, which will corrode them.

Metals in a plumbing (i.e. wet) system need to be either isolated from each other or be galvanically compatible.

This applies to roofing, too. Nail the flashing down with galvanically compatible nails, or you'll find the flashing all comes loose after a couple years.

> Stainless in (or near) contact with copper with moisture between them forms a battery, which will corrode them.

Not really?

A battery has two paired half reactions. Something gets oxidized, something gets reduced, and electrons flow through the conductive bits.

So if you have some metallic zinc, and you have some copper ions, and you have some metallic copper, and you have electrical contact, zinc will be oxidized, copper ions will be reduced and plate into the copper, and current will flow. Once the zinc is gone, if you had galvanized steel to start with, the iron will oxidize.

Now try stainless steel. The half-reaction involving the stainless steel, hmm, doesn’t involve iron — the iron is physically separated from the electrolyte by the passive layer. Chromium? Barely - a tiny bit oxidizes and then it stops. We’re left with 2H+ + 2e- -> H2. Which can happen without the stainless steel too, but with more available surface area, it’s faster.

So a lot of stainless steel will accelerate the corrosion of a small amount of copper. But the reverse has little effect.

There is apparently a real concern the with H2: some grades of stainless steel are apparently rather susceptible to hydrogen embrittlement.

I'm not a chemist, but I believe Boeing when they told me never to place copper in contact with stainless, due to galvanic corrosion. Corrosion is the mortal enemy of all airplanes.

You'll also find the same if you google for copper and stainless galvanic compatibility.