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State's instructions for sampling drinking water for lead "not best practice"

A table filled with bottles of Flint water (both clear and brown)
Flint Water Study
Researchers at Virginia Tech received samples of Flint water (both clear and discolored) from residents.

The Flint water crisis has uncovered all kinds of details about how cities test the safety of their drinking water.

In particular, critics say the state is giving bad advice on testing drinking water for lead.

The state of Michigan tells cities to do something called pre-flushing.

The instructionstell people to turn on their cold water tap and let it run for five minutes (that's the pre-flushing part). Then, people are supposed to wait six hours before taking their water sample.

Critics say pre-flushing is one of many practices used to skirt the intent of the EPA’s lead and copper rule.

Lee Anne Walters wants to see the rules changed. Her four-year-old son had elevated lead levels in his blood after Flint started using the Flint River as a water source.

"I want the loopholes for the lead and copper rule out. I’m not going to stop until that happens,” she says.

She’s speaking at a national meeting this week in Virginia about proposed revisions to the lead and copper rule.

The trouble with pre-flushing

Marc Edwards is a professor at Virginia Tech University and an expert on water treatment. He says a lot of cities around the country do this pre-flushing when they test drinking water for lead. But he argues they should not.

“It cleans the pipe of both soluble lead and also to the extent there’s little lead particles in the wall of the pipe they’ll be swept out of the pipe so they’re not present when you sample the next day,” he says.

"Who sits around and flushes their kitchen tap every night for five minutes before they go to bed? Nobody."

He says that means you can end up skewing your lead sample results lower, and make it appear that you have less lead in your drinking water than you actually do.

“Why add this complexity on and tell people to do something they don’t normally do? Who sits around and flushes their kitchen tap every night for five minutes before they go to bed? Nobody.”

Here’s the thing about pre-flushing...

It’s not banned under the federal lead and copper rule, but the EPA says cities should not do it.

Peter Grevatt directs the EPA’s Office of Groundwater and Drinking Water.

"The idea of pre-flushing, typically that’s something that would not be done. It’s not prohibited under the rule, but at the same time we don’t view it as best practice."

Grevatt says they to want work with states and water systems so they understand this.

This June, an EPA employee expressed concern in a internal memo obtained by the ACLU that this practice was being used to collect water samples in Flint.

In the memo, EPA Regulations Manager Miguel Del Toral wrote that pre-flushing has been shown to "result in the minimization of lead capture and significant underestimation of lead levels in the drinking water."

He continues:

"Although this practice is not specifically prohibited by the LCR, it negates the intent of the rule to collect compliance samples under 'worst-case' conditions, which is necessary for statistical validity given the small number of samples collected for lead and copper under the LCR. This is a serious concern as the compliance sampling results which are reported by the City of Flint to residents could provide a false sense of security to the residents of Flint regarding lead levels in the water and may result in residents not taking necessary precautions to protect their families from lead in the drinking water."

Del Toral wrote that he raised this concern with the Michigan Department of Environmental Quality, and "the MDEQ has indicated that this practice is not prohibited by the LCR and continues to retain the 'pre-flushing' recommendation in their lead compliance sampling guidance to public water systems in Michigan."

Virginia Tech professor Marc Edwards says he joined Del Toral in expressing concern to the MDEQ about the agency's testing guidelines.

“They were told point blank by Miguel Del Toral and myself earlier this year that the effect of the pre-flush was to hide the lead and it was recommended that they stop it. And they put in writing that they were not going to do that and they had no interest in doing that.”

Edwards is referring to documents Virginia Tech obtained from the MDEQ under the Freedom of Information Act. Notes from a July 21, 2015 conference call between the EPA and MDEQ say:

“MDEQ is not interested in changing its position on pre-flushing until new regulations come out. They also pointed out that the pre-flushing instructions are not requirements, but suggestions. The Michigan pre-flushing instructions were designed as a way to ensure that sampled faucets were not stagnant for an excessive period of time beyond the targeted 6 hour (i.e. rarely used faucets or when a homeowner has been gone for an extended period of time).”

That last statement about how long water can be stagnant in the pipes before sampling is also a point of contention.

An official EPA memo from 2004 says there's not a limit:

The LCR also defines a proper sample as a first draw sample, 1 liter in volume, that is taken after water has been standing in plumbing for at least six hours, and from an interior tap typically used for consumption - cold water kitchen or bathroom sink tap in residences. [40 CFR 141.86(b)(2)] There is no outer limit on standing time.

The DEQ did not provide anyone for an interview for this story.

In an email, DEQ spokesman Brad Wurfel said, "We're reviewing the testing protocol as part of our internal review. When we've got something to announce, I'll let you know."

It’s important to note, this goes beyond Flint.

A number of cities around Michigan follow the state's pre-flushing guidelines.

A number of cities around Michigan follow the state’s pre-flushing guidelines. Ann Arbor, East Lansing and Detroitall said they tell people to flush their tap water for five minutes.

But the City of Flint has recently changed the way it tells residents to sample water for lead.

Mike Glasgow is Flint’s Utilities Administrator. He says a few weeks ago, they removed the pre-flush recommendation from the instruction sheetthey hand out to residents who want to test their water for lead.

“We removed the pre-flush after recommendations from experts in the field and a few of EPA’s researchers, so we’re going to err on the side of caution while we remove the flushing,” he says.

Glasgow says they’ve asked the MDEQ to let them keep their new "no-flush" method for the next round of official water testing for compliance with the lead and copper rule.

He says he’s waiting to hear how state officials respond.

Mark Brush and Lindsey Smith contributed reporting to this story.

Rebecca Williams is senior editor in the newsroom, where she edits stories and helps guide news coverage.
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