Table 1.3 Nitrite Monitoring Requirements System Monitoring type Source Sampling frequency Notes type All PWSs must take one Initial Routine All Any sample in the first 3 year Sampling compliance period. After the initial sample, systems where result is < Reduced Sampling All Any ½ the MCL shall monitor once per nine year. Must collect 4 State may allow a system to consecutive quarterly reduce to annual sampling Increased Sampling All Any samples following any after determining the > ½ MCL one sample that is > ½ system is R&C below the MCL MCL. Compliance with the MCL Confirmation sample must is determined by be collected within 24 hours Increased Sampling averaging results of initial All Any of the systems receipt of >MCL and confirmation the analytical results of first samples. sample. Waived for any systems Waivers must be issued in Waivers All Any that chlorinate. writing. Code of Federal Regulation (§141.23(e)(1-3)); (§141.23(i)(3)) & (§141.23(f)(2))
Table 1.3 Nitrite Monitoring Requirements Monitoring type System type Source Sampling frequency Notes Initial Routine Sampling All Any All PWSs must take one sample in the first 3 year compliance period. Reduced Sampling All Any After the initial sample, systems where result is < ½ the MCL shall monitor once per nine year. Increased Sampling > ½ MCL All Any Must collect 4 consecutive quarterly samples following any one sample that is > ½ MCL State may allow a system to reduce to annual sampling after determining the system is R&C below the MCL. Increased Sampling >MCL All Any Compliance with the MCL is determined by averaging results of initial and confirmation samples. Confirmation sample must be collected within 24 hours of the systems receipt of the analytical results of first sample. Waivers All Any Waived for any systems that chlorinate. Waivers must be issued in writing. Code of Federal Regulation (§141.23(e)(1-3)); (§141.23(i)(3)) & (§141.23(f)(2))
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