CO HB1099

Water Quality Control Commission must issue written guidance by January 1, 2027 on total maximum daily load (TMDL) development, addressing data collection best practices, analytical methods, quality assurance, and geographic/hydrological accuracy

Division of Administration in the Department of Public Health and Environment must determine TMDLs for state waters using credible data starting January 1, 2028

TMDL is defined as the calculation of the daily maximum amount of a pollutant from all sources allowed to enter state waters while meeting water quality standards

Credible data for TMDL determinations must include data collected within five years before the determination and relevant historical data

Commission must solicit input from interested parties before issuing the TMDL guidance