lead in the water
June 25, 2009 9:27 PM   Subscribe

So I just got my water tested, and the lead level was about 43 parts per billion. Should I be concerned?

I had the tap water tested at my house, and the result was that they found 42.9 parts per billion, which is much higher than the EPA action level (15ppb). I'm going to get some quotes on replacing the lead water pipe from the street (which I think is the source), but should I be immediately concerned?
posted by anonymous to Home & Garden (9 answers total)
http://www.epa.gov/ogwdw/lead/lead1.html has some good info.

Federal standards initially limited the amount of lead in water to 50 parts per billion (ppb). In light of new health and exposure data, EPA has set an action level of 15 ppb. If tests show that the level of lead in your household water is in the area of 15 ppb or higher, it is advisable - especially if there are young children in the home - to reduce the lead level in your tap water as much as possible. (EPA estimates that more than 40 million U.S. residents use water that can contain lead in excess of 15 ppb.)

posted by atmosphere at 9:38 PM on June 25, 2009

If you have kids you may want to drink more bottled water. If not, I wouldn't panic at this time, but I'd probably have a second test run first and assuming you're seeing the same kind of results, then go ahead with those quotes. Or maybe just get a really good filtering system since, even if your branch pipe is lead, that may not be where the lead is coming from.

This isn't an acute poisoning kind of situation where you're going to die any moment if you drink the water.
posted by Kid Charlemagne at 9:45 PM on June 25, 2009

That's 43 parts per billion more than homeopathic medicine!

In Australia the maximum acceptable level of lead is 0.01 mg/L (down from 0.05 mg/L). I don't know what that works out to be in ppb but 42.9 seems like bad news in the long run, less in the short run. Lots of fun facts about lead poisoning on the Wikipedia page!
posted by turgid dahlia at 9:56 PM on June 25, 2009

since parts per million is typically measured by weight (correct me if I'm wrong), mg/L should be equal to ppm, since one kg of water equals one liter of water, and there are 1,000,000 mg in a kg.

Did I miss something here?
posted by Precision at 10:05 PM on June 25, 2009

There could be a number of things influncing the result, and a retest by an independent lab (definitely not someone selling water treatment systems) is certainly appropriate. Often piping and fixtures can leach lead into water supplies and a simple solution to those issues is to run the water a bit before consuming (your exposure to most metals in water via dermal contact is very limited compared to exposure via consumption). Toxicologists often recommend drawing time series samples (initial draw, 5 minutes, 15 minutes) to see where the lead might be coming from; initial draws get water that has been in contact with metals in the home's fixtures for the longest time and therefore has the potential for the most leaching of metals. Presuming you're on a public water system, they should have sampling data describing the quality of water as it leaves the plant and, depending on size, they may have a lead sampling program designed to test those connections that are most likely to have lead solder in the piping (mid 1980's and eariler, though fixtures haven't been as closely regulated). The disinfection process chosen by the public water system can also potentially cause leaching of lead, such as the when Washington DC's supply switched to chloramines (great for disinfection, but tragically caused increased leaching of piping in older & poorer neighborhoods). In terms of an immediate concern, particularly if you have children, take action to get alternate water for consumption as lead is strongly linked to developmental issues, but spend some time examining the situation before taking potentially expensive steps that may not alter your exposure and re-test to confirm that whatever steps you take have made a difference.
posted by pappy at 10:15 PM on June 25, 2009 [1 favorite]

43 ppb = 43 micrograms/liter = 0.043 mg/L = 0.043 ppm; about 3x the EPA primary drinking water standard.
posted by pappy at 10:19 PM on June 25, 2009

I don't think you need to be alarmed, but its definitely worth trying to reduce the lead concentration as others have mentioned.

A note on the standards: EPA has established a goal (or MCLG) of 0 lead in drinking water as the level below which there are no known or suspected health effects. Recognizing that 0 isn't realistic since, for centuries, lead has been a part of plumbing systems as pipe, solder, and in brass, the EPA established the drinking water standard (or MCL) as specific treatment techniques required to prevent corrosion (see the Lead and Copper Rule or the summary pdf).

They also established an action level at 15 ppb to trigger additional monitoring and treatment requirements for the water purveyor. If more than 10 percent of homes in the service area have lead levels above 15 ppb then they need to take action to reduce lead until they are below the threshold. As far as I can tell 15 ppb is not a level at which health effects necessarily occur.

In the short term, the recommendations seem to be 1) running the tap before getting water for drinking or cooking, 2) using only cold water for drinking, and 3) consider a brita or faucet mounted filter.

In the longer term, it's probably worth finding and eliminating the source. It could be lead pipe, lead solder, or older brass fittings. A plumber should be able to help determine which you've got. I wouldn't necessarily assume that the service is lead, unless you know for sure. But if it is, it could be that your purveyor has a program to help replace lead service lines, DC and NY do for example.

Pappy's advise on re-sampling seems like a good idea, particularly if your first sample was taken straight from the tap after a period of stagnation. Analysis for lead in water should be fairly cheap, as opposed to re-plumbing a house. So it pays to spend some effort defining the problem.

Finally, as pappy and Precision pointed out, for water, 1 mg/L is equal to 1 ppm or 1000 ppb, so 0.01 mg/L is 10 ppb, meaning that Australia's standards are roughly comparable to the US.
posted by rube goldberg at 11:10 PM on June 25, 2009

That is astronomical. Don't drink any more of it without filtering (which is not that hard to to, with a Pur or Brita pitcher).

What I usually do is test cold water, first draw out of the tap, first thing in the morning. If you have a Moen faucet, make sure it was cold and only cold that was sampled. Anyway, I then let the water run for 15 seconds or so to test it again. If it's clear, then I assume it's the solder and brass in the faucet that is the source. (I do this as part of my job.)

But if you do have any lead pipes, you really need to replace them. Plus, never consume any water that has been in the water heater. Hot water leaches more contaminants out of the plumbing.

But yeah, make sure that whoever tested it is not in the biz of remediation. If this test it legit, you have a problem that you need to get on right away.
posted by Danf at 8:09 AM on June 26, 2009 [2 favorites]

Another environmental chemist here: as other have said, that's not safe drinking water. You need to think about remediation of some sort.
posted by bonehead at 9:14 AM on June 26, 2009 [1 favorite]

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