must be something in the water...
February 22, 2011 11:22 PM   Subscribe

This is a question for anyone who knows about houses from the inside out: Do homes ever use aluminum pipes for plumbing? We just had our water tested by the national center for water quality at Heidelberg University using samples from two separate faucets in our home. One sample came back totally normal; the other had double the rate of acceptable aluminum per billion parts. Readings for all other substances were fairly close to each other between the two faucets (and except for the aluminum, no other concern.) Why could one faucet have a higher aluminum rate than another in the same home?

I thought pipes were made of copper; is this not true? Home was built in the early 1980s.

I have a call in to the water testers, but wanted to research on my own a bit before they call me back. I am not very optimistic about their being able to give me a reason for the aluminum -- they pretty much just do the testing, I think.
The local municipal water supply reports no surplus of anything.
posted by Tylwyth Teg to Home & Garden (11 answers total)
Aluminum pipes are generally not suitable for most water installations. As far as I know they have never been approved for potable water installations in Germany (Verboten :-) ). I'm assuming that you are in Germany or is there a Heidelberg university in the US?
Aluminum pipes can corrode under alkaline and acidic conditions. The famed passivation properties of aluminum do not come under consideration here. Even though, many heating elements that come into direct contact with water are made out of aluminum (hello coffeemaker).
So either there was a mistake made in the lab or some earlier owner tinkered with the pipes on his own. I really do not think that you have aluminum pipes in your water system.
In the early 80's pipes were probably soldered/brazed. Maybe some of the solder used contains some aluminum? (Different solder, different aluminum content.)
Did you consider your method of sample collection?
Contamination in the parts per billion range can be introduced almost anywhere.
I would recommend that you repeat the analysis. Alternatively- if the "contaminated" faucet is in the bathroom- you could stop worrying. If you generally just shower or brush your teeth with that water, I wouldn't worry.
posted by mmkhd at 2:28 AM on February 23, 2011

As an aside, some modern pipes are made with aluminum but thats just for structural integrity. The real pipe is an inner plastic tube.
posted by mmkhd at 2:31 AM on February 23, 2011

Was the high-aluminum sample from a bathroom tap that could have been contaminated with a bit of toothpaste? Many toothpastes contain aluminum compounds, and a tiny smear on a tap might conceivably have been washed into your sample.
posted by le morte de bea arthur at 3:38 AM on February 23, 2011 [1 favorite]

I am electrician. I have worked in construction for years. I am also a scraper on the side. I collect scrap metal to take to the metal recycling yard for money.

I collect my own copper wire scraps, of course - but I will also collect any metal worth hauling. Aluminum is definitely worth hauling.

I have worked at many whole home re-models. I have never once seen aluminum plumbing pipes. Never heard of it. Several plumbers know me, they would have set it aside for me at jobs. I am not a plumber, but I can almost guarantee that such a thing is never found in Florida, where I live.
posted by Flood at 4:12 AM on February 23, 2011

Could it be the fixture itself? If that's a possibility consider getting the sample from the source at the wall. If the setup is anything like US plumbing then there should be a shutoff valve under the sink and then a hose from there to the fixture. Consider removing the hose (properly shutting off the water, of course) and getting a sample straight from there. If it reads like everything else in the house then it'd be the fixture. They're not all that hard to replace, in most situations.
posted by wkearney99 at 6:34 AM on February 23, 2011

The standard in the US post-war was galvanized steel plumbing until somewhere around the late 60s-early 70s when the switch was made to copper. A house built in the US in 80s would have almost certainly been copper plumbing. It's possible the original builder would have used an alternative, say at the special request of the owner if it was a custom build.

It's also possible a previous owner could have made modifications.

Aside from copper, the only thing really used in the US is PEX, which is plastic. But the only other option is galvanized steel. But then you might have lead in the water (if anything), not aluminum.

I don't even know where one could get aluminum plumbing. Never heard of it. And I can't imagine why anyone would want to use it.
posted by thatguyjeff at 7:33 AM on February 23, 2011

Municipal water contains aluminum as a clearing agent. If you have high levels of Al then its probably coming from the source, not a local pipe. You may want to get your water retested if one lab says theres a lot of Al in one facet and not the other.
posted by damn dirty ape at 7:36 AM on February 23, 2011 [1 favorite]

No, aluminum is not used for plumbing pipes. It's against code in Texas and it would be much more difficult to work with than the cheaper, legal alternatives. That said, I've seen that people have done some wacky stuff, especially for plumbing kludges so it's certainly possible that at some point someone had aluminum pipe laying around and the skill/tenacity to solder/epoxy/tape/pressure fit it in somewhere.
posted by cmoj at 10:22 AM on February 23, 2011

I don't know much about plumbing, but I have set up an assay to measure aluminium before. From my experience, contamination was an unbelievably huge problem. Aluminium is the 3rd most abundant element on the planet, it gets everywhere. I had to be completely rigorous in washing everything I used and even then it sometimes snuck in. I'm not criticising the measurements, but I would certainly want to get them repeated before doing any further investigation. Do you mind if I ask why these measurements were being done?
posted by *becca* at 11:03 AM on February 23, 2011

Have you replaced the faucet screen / aerator? You should try that.
posted by WeekendJen at 2:19 PM on February 23, 2011

Response by poster: Do you mind if I ask why these measurements were being done?

THanks so much so far, everyone!
We have sediment/residue in our tub after the hot water evaporates. The local utilities people said it was probably just calcium but since it's often gray or sandy colored I wanted to make sure. (BTW this particular Heidleberg U is in Ohio.)
The aluminum-heavy test only came from that bathroom (tub) tap with a hot water sample. I think now after doing a whole lot of googling that the elevated AI levels are maybe a normal product of the hot water heater's anodyne rod, and that it goes away with cold water.
If this makes no sense and you're still reading, please do let me know!
Thanks again.
posted by Tylwyth Teg at 3:20 PM on February 23, 2011

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