Our sampling of 252 homes demonstrates a high lead in water risk: Flint should be failing to meet the EPA Lead and Copper Rule

Over the weekend, we analyzed all samples shipped to Virginia Tech from Flint to date. Flint residents have already returned an astonishing 84% of the sample kits we sent out (252 out of 300 samples). We will continue to analyze water samples as they are returned. However, mathematically, even if the remaining 48 samples returned have non-detectable lead, our conclusion will not change — FLINT HAS A VERY SERIOUS LEAD IN WATER PROBLEM.

Forty percent (40.1%) of the first draw samples are over 5 parts per billion (ppb). That is, 101 out of 252 water samples from Flint homes had first draw lead more than 5 ppb. Even more worrisome, given that we could not target “worst case” homes with lead plumbing that are required for EPA sampling, Flint’s 90%’ile lead value is 25 ppb in our survey. This is over the EPA allowed level of 15 ppb that is applied to high risk homes. This is a serious concern indeed. Several samples exceeded 100 ppb, and one sample collected after 45 seconds of flushing exceeded 1000 ppb.

We now advise Flint consumers to heed EPA information that advises consumers on how to avoid adverse health effects from exposure to excessive lead in drinking water. The main concern is related to water used for drinking or cooking. With the exception of one home that we sampled which had astronomical levels of lead, the levels of lead detected in Flint were safe for bathing, showering, toilet flushing and watering lawns/gardens.

Until further notice, we recommend that Flint tap water only be used for cooking or drinking if one of the following steps are implemented:

  • Treat Flint tap water with a filter certified to remove lead (look for certification by the National Sanitation Foundation (NSF) that it removed lead on the label), or
  • Flush your lines continuously at the kitchen tap, for 5 minutes at a high flow rate (i.e. open your faucet all the way), to clean most of the lead out of your pipes and the lead service line, before collecting a volume of water for cooking or drinking. Please note that the water needs to be flushed 5 minutes every time before you collect water for cooking or drinking. For convenience, you can store water in the refrigerator in containers, to reduce the need to wait for potable water each time you need it.

We do not issue this warning lightly, and note that our concern is based on several lines of evidence. First, scientifically, we predicted based on past research that the Flint River water chemistry would create a serious lead in water problem. Second, we confirmed the very high corrosivity of the Flint River water for lead in our laboratory testing at Virginia Tech. Third, for some reason that no one has yet explained to us, the Flint River water was introduced into the pipe distribution system without any measures (or even a plan) to reduce its corrosivity. We are therefore very perplexed by recent MDEQ assertions that the situation in Flint is normal. Finally, we have the results of our survey of 252 homes conducted with the assistance of Flint consumers. Because of the very serious and permanent health damage that arises from lead exposure, we feel that this problem requires immediate public health warnings and intervention– we provide that for Flint consumers in this report.

Another mystery that must be examined very carefully in the days and weeks ahead: How is it possible, that Flint “passed” the official EPA Lead and Copper Rule sampling overseen by MDEQ? In our experience, following the EPA site selection criteria targeting homes with the highest risk for lead, the MDEQ sampling should have found much worse results than our sampling. Instead, MDEQ is asserting that the lead levels in Flint are much lower. Hence, we call on the U.S. EPA and others, to conduct a detailed audit of the 2014 and 2015 LCR sampling round overseen by MDEQ in Flint, to determine if it was conducted consistent with requirements of the law.

Primary Author: Dr. Marc Edwards

Samples Analysis: Dr. Jeffrey Parks, Anurag Mantha

Acknowledgements: Siddhartha Roy

11 thoughts on “Our sampling of 252 homes demonstrates a high lead in water risk: Flint should be failing to meet the EPA Lead and Copper Rule

  1. MDEQ will never acknowledge its fault and USEPA will rely on MDEQ. The best solution is to publish the results in a peer reviewed scientific magazine with criticism of MDEQ results. Then the job will be accomplished and may lead to state or federal legislative hearings.

  2. Did Virginia Tech offer to coordinate sampling sites with the City of Flint or MDEQ?

    Did Virginia Tech offer to split samples with City of Flint, EPA,, or

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