Bill > HB1099

This bill establishes new standards and requirements for water quality data management in Colorado, specifically focusing on Total Maximum Daily Load (TMDL) calculations. The bill defines TMDL as the maximum amount of a pollutant allowed to enter state waters while meeting water quality standards. By January 1, 2027, the water quality control commission must develop written guidance for TMDL development, which will include best practices for data collection, analytical methods, data quality assurance, and geographic accuracy. Starting January 1, 2028, the state's public health and environment division will be required to determine TMDLs using credible data, which includes information collected within the previous five years and relevant historical data. This legislation aims to improve the scientific rigor and precision of water quality assessments by establishing clear guidelines for data collection and analysis, ensuring that water quality standards are based on comprehensive and reliable information. The bill will take effect after the standard legislative review period, with a potential referendum vote in November 2026 if challenged.