Correspondence among

Thought folks might find these documents informative: Attached to this message are a couple of documents that were prepared over a decade ago that discuss excessive stagnation and sample invalidation under the LCR. They were prepared in response to questions from the Washington Post and other news media about invalidation of some samples collected in the Lansing Board of Water Light service area. The first document is an internal memo that identifies language in the federal preamble to and in EPA guidance for the LCR that discuss the need to collect samples from homes that have experienced “typical residential water use during the day before the compliance sample is collected.” The second document is a report prepared to explain why we “invalidated” samples for excessive stagnation in Lansing. It was in the aftermath of this event when EPA eliminated the ability of state programs to invalidate sample results based on excessive stagnation that ed the Michigan Public Water Supply Program to develop a recommendation that communities advise residents participating in their compliance monitoring to flush the designated sampling tap 6 to 8 hours before sample collection (the night before in most cases) to ensure that this tap was not experiencing excessive periods of stagnation. We did not want subsequent regulatory requirements to be imposed based on water quality information that did not accurately reflect the regulatory intent. This briefing report also xxxEND_PAGE:deq04_b214_3461_3462_1 discusses the fact that the regulatory monitoring scheme was not intended to represent human intake, but was based upon sampling a statistically significant number of residences containing leaded plumbing materials as a measure of successful water treatment efficacy. xxxEND_PAGE:deq04_b214_3461_3462_2