Frequent Questions

When a public water system (PWS) asks its customers to collect first-draw samples for lead testing compliance, how long can the PWS wait before performing acidification on the samples?

A PWS has up to 14 days after the first-draw samples are collected to perform the acidification. After acidification, the samples must stand in the original containers for the time specified in the approved EPA method before the samples can be analyzed (40 CFR 141.86(b)(2)).

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