Frequently Asked Questions

Updated: Feb 1, 2016

This is a compilation of all questions we have been asked so far. If you have a question, please send us an email to and we will try our best to include them.

Also read: Some Common Misunderstandings of Flint’s Lead in Water Problem

Questions on Legionella: Go here.

Questions on Citizen Testing: Go here.

See our Reddit Ask Us Anything session.

Newest Question: What is the deal with the new concerns about filters not working if water lead is above 150 ppb?

A little background.  Virginia Tech has done over a decade of research on the effectiveness of lead faucet and pitcher filters.  We were the first to show that the inexpensive Brita pitcher filters, did not work effectively, if water lead was present in the form of little suspended particles. The Brita pitcher filters worked great to remove lead that was dissolved (i.e., soluble in water, like sugar and salt dissolve when added to water). On the basis of our work, the National Sanitation Foundation made their testing protocol much tougher, and the Brita pitcher-style filters lost their certification for lead removal.

To get National Sanitation Foundation certification for lead removal nowadays, the filter has to pass tests using both particulate and dissolved lead. When the new improved certified filters came onto the market, we were skeptical and did a lot of testing.  In general, they worked really well. So even though the certification test is only done up to 150 ppb, they worked even at much higher levels. If my family was in Flint, and I had a certified lead filter installed, I would let my family and children drink the filtered water.

But as a scientist you always have to test to see if you are wrong. You cannot be too careful.  Earlier this year, when we received the high lead samples from Lee-Anne Walters, we tested one of her worst samples with a Zero Water filter.

Lead Going Into Filter:   13,200
Lead Coming Out of Filter: 20 ppb
Lead Removal:  99.85%

So this filter was great because it removed 99.85% of the lead, but on the other hand, it was also not perfect because 0.15% of the lead was not removed.  Because this is the worst sample we have ever tested, and even at Lee-Anne’s house lead was usually lower than this worst case, this is a very encouraging result.  In other tests, we found that even with water lead up to 1000 ppb, the certified filters were always well below 10 ppb.  Of course, if less lead is going into them, they will do even better.

What about the announcement from the Feds last Friday about the concerns of exceeding the 150 ppb rating?  The Feds, too, are trying to be careful, and make sure the filters are working for the water actually present in Flint. They are going out to test them, and make doubly sure that the filters work as expected, and that they dramatically reduce filtered water lead levels.

Stay tuned for the results. The expectation is that they will find out that everything is ok. We are happy the Feds are doing this extra testing.

Is it okay to bathe or shower in Flint’s water?

This is really not a significant concern. A good reference on this subject states (emphasis added):

 Dust and soil that contain lead may get on your skin, but only a small portion of the lead will pass through your skin and enter your blood if it is not washed off. You can, however, accidentally swallow lead that is on your hands when you eat, drink, smoke, or apply cosmetics (for example, lip balm). More lead can pass through skin that has been damaged (for example, by scrapes, scratches, and wounds). The only kinds of lead compounds that easily penetrate the skin are the additives in leaded gasoline, which is no longer sold to the general public. Therefore, the general public is not likely to encounter lead that can enter through the skin.

 If anything, lead in water would tend to pose a lower risk than lead in dust or soil, because the lead has a strong tendency towards staying in the water.

In the last 25 years, I have only recommended that children not bathe in lead-contaminated water one time: for a case in Flint that was unusually bad where lead in water averaged over 2000 parts per billion for over 25 minutes of flushing. In the vast, vast majority of cases, there would not be a significant health concern from lead exposure due to bathing or showering in potable water.

When will we be able to say that Flint’s water is “safe” to drink again, and lift the water emergency?

For us, we’d be satisfied if Flint was protected by the same law that applies to every other city in the United States of America. That law requires: 1) corrosion control, and 2) monitoring that proves more than 90% of high risk homes sample below the EPA Action Level of 15 ppb. Flint now has a corrosion control plan, but they have not been monitoring according to Federal Rules. Will their next round of monitoring follow Federal Rules? One would hope so. If and when that occurs, and they demonstrate they are under the 15 ppb EPA action level, we believe that a reasonable person could say the water is “safe” and the water emergency could be lifted. Until that time, Flint water cannot be reasonably considered to meet that minimum legal standard.

There is also a strong argument that the current EPA standard of less than 15 ppb in > 90% of homes, does not meet a reasonable modern definition of safety. But that is a larger national debate, and we’ll be satisfied if Flint simply met the existing minimum safeguards.

How good a role will corrosion control play in bringing Flint’s lead levels down? What are your thoughts on replacing all lead service lines in Flint?

There is certainly permanent damage to the city and consumer owned pipes from corrosion; however, that damage is mainly to the pipe wall. That means there is a reduced lifetime, and the pipe will fail or need replacement sooner. Except for plastic pipes which would not have been damaged.

In terms of lead in water, the anticorrosion agents (i.e., phosphate) should be able to restore the pipe performance to where it was before the switch. It might take a while to get the city back below the EPA water lead action level, and it might take even longer to get to even lower lead levels that were likely present from before the switch, but Flint will get there.

Of course, no anticorrosion control is perfect for lead leaching to water. Flint will still have a problem with water lead, just like other cities with lead pipes. There is a growing consensus that corrosion control is not protective enough for public health over the long term, even though it is a critical first step.

Personally, I would like to see the Federal Government, make Flint into a test city, to learn how we can get lead pipes out of the ground once and for all.

But we have to do it carefully. No one has ever completely replaced thousands of lead pipes before, except Lansing MI, and they had it relatively easy.

Lansing owned the whole lead pipe from the house to the street, and they also knew where the lead pipes were, because they had good records.

The accuracy of Flint’s records are presently unknown, and there is shared ownership of service lines.

Lead service line replacement is a serious business. You have to tap into water mains that are normally at high pressure, dig up streets, avoid other critical infrastructure (gas, cable, electric), follow the plumbing code and electrical codes, navigate both public/privately owned property, and negotiate contracts with a city. And let’s not forget that the existing service line is a hazardous material, with about 70 years of lead rust on it. In other cities where they took half measures or did pipe replacement carelessly (i.e., Washington D.C. from 2004-2009), they made the problem worse and actually increased the likelihood of childhood lead poisoning. Realistically, this is a process that would take years to do correctly, even if the money were made available today.