§ 141.625. Conditions requiring increased monitoring.

Code of Federal Regulations

Title 40. Protection of Environment

Chapter I. ENVIRONMENTAL PROTECTION AGENCY

Subchapter D. WATER PROGRAMS

Part 141. NATIONAL PRIMARY DRINKING WATER REGULATIONS

Subpart V. STAGE 2 DISINFECTION BYPRODUCTS REQUIREMENTS

Current through July 3, 2019

§ 141.625. Conditions requiring increased monitoring

(a) If you are required to monitor at a particular location annually or less frequently than annually under §141.621 or §141.623, you must increase monitoring to dual sample sets once per quarter (taken every 90 days) at all locations if a TTHM sample is >0.080 mg/L or a HAA5 sample is >0.060 mg/L at any location.
(b) You are in violation of the MCL when the LRAA exceeds the subpart V MCLs in §141.64(b)(2), calculated based on four consecutive quarters of monitoring (or the LRAA calculated based on fewer than four quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters). You are in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA if you fail to monitor.
(c) You may return to routine monitoring once you have conducted increased monitoring for at least four consecutive quarters and the LRAA for every monitoring location is [LESS THAN EQUAL TO]0.060 mg/L for TTHM and [LESS THAN EQUAL TO]0.045 mg/L for HAA5.

Cite as 40 C.F.R. § 141.625