Table 3.1 SOC Monitoring Requirements System Monitoring type Source Pop. Sampling frequency Notes type Sampling All CWSs required Initial Routine Four consecutive quarterly samples & Any Any unless Sampling during initial compliance period. NTNCWs waiver is granted. May be reduced May be reduced to 1 sample during each <3,300 ONLY if consecutive compliance period. All CWSs system had Reduced monitoring & Any no detects in NTNCWs the initial May be reduced to two quarterly of >3,300 samples in 1 year during each routine consecutive compliance period. sampling. Must collect 1 sample per quarter until Increased All CWSs state determines sampling results are monitoring & Any Any reliably and consistently (R&C) below (If exceed detection NTNCWs MCL. Systems must take at least 4 limit or MCL) quarterly samples. May be reduced ONLY if the Reduced State may reduce sampling frequency to state Monitoring All CWSs 1 sample annually, taken during the determines (once state & Any Any same quarter which previously yielded that determines system NTNCWs the highest analytical result. sampling is R&C below MCL) results fall R&C below the MCL. Systems granted waivers are not required to monitor. System may be Waivers All CWSs granted waiver if contaminant is not must be Waivers & Any Any detected in 3 consecutive annual issued in NTNCWs samples. Systems also eligible for use writing. waiver. Waivers must be renewed every 3 years. Code of Federal Regulation (§141.24(h)
Table 3.1 SOC Monitoring Requirements Monitoring type System type Source Pop. Sampling frequency Notes Initial Routine Sampling All CWSs & NTNCWs Any Any Four consecutive quarterly samples during initial compliance period. Sampling required unless waiver is granted. Reduced monitoring All CWSs & NTNCWs Any <3,300 May be reduced to 1 sample during each consecutive compliance period. May be reduced ONLY if system had no detects in the initial of routine sampling. >3,300 May be reduced to two quarterly samples in 1 year during each consecutive compliance period. Increased monitoring (If exceed detection limit or MCL) All CWSs & NTNCWs Any Any Must collect 1 sample per quarter until state determines sampling results are reliably and consistently (R&C) below MCL. Systems must take at least 4 quarterly samples. Reduced Monitoring (once state determines system is R&C below MCL) All CWSs & NTNCWs Any Any State may reduce sampling frequency to 1 sample annually, taken during the same quarter which previously yielded the highest analytical result. May be reduced ONLY if the state determines that sampling results fall R&C below the MCL. Waivers All CWSs & NTNCWs Any Any Systems granted waivers are not required to monitor. System may be granted waiver if contaminant is not detected in 3 consecutive annual samples. Systems also eligible for use waiver. Waivers must be renewed every 3 years. Waivers must be issued in writing. Code of Federal Regulation (§141.24(h)
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