Violation 40 C.F.R. Part 141 Subpart U, Stage 2 Disinfectant and Disinfection Byproducts Rule (Stage 2 DBPR), for failure to submit standard monitoring plan by schedule 4 due date. AO to establish an alternate compliance schedule for the Respondnet to comply with the IDSE requirements of the Stage 2 DBPR. The District failed to conduct sampling during Period 4.