HB1099 would require Colorado’s Water Quality Control Commission to issue written guidance by January 1, 2027, for how total maximum daily loads (TMDLs) should be developed. A TMDL is the calculated maximum amount of a pollutant that can enter state waters while still meeting water quality standards. The guidance must address data collection best practices, reliable analytical methods, data quality assurance, and the appropriate geographic and hydrological precision for TMDL development.
Beginning January 1, 2028, the bill directs the Division of Administration in the Department of Public Health and Environment, as directed by the commission, to determine TMDLs for state waters using credible data. The bill defines credible data to include both data collected within the five years before the TMDL determination and relevant historical data. It also adds a statutory definition of “total maximum daily load” to Colorado’s water quality laws.
Impact
The bill would amend Colorado’s water quality statutes in Title 25, Article 8 by adding a formal definition of TMDL and by expanding the Water Quality Control Commission’s rulemaking and guidance responsibilities. It would also impose a new operational requirement on the Department of Public Health and Environment’s division of administration to use specified categories of credible data when determining TMDLs for state waters. In practice, the bill would standardize how pollutant load limits are developed and could affect state water quality planning, permit support, and pollution control decisions for regulated dischargers, watershed stakeholders, and local governments.
Sentiment
The available voting history suggests the bill did not advance out of the House Energy & Environment Committee, where it was postponed indefinitely on a 12-0 vote. That unanimous committee action indicates no recorded opposition in the vote itself, but it also shows the bill did not receive enough support to move forward. No committee transcript was provided, so the broader discussion record is limited; based on the bill’s subject matter, the measure appears to have been treated as a technical water-quality standards bill rather than a highly partisan proposal.
Contention
The main policy issue is how prescriptive the state should be in directing TMDL methodology. Supporters would likely favor clearer statewide standards, better data quality, and more consistency in pollutant load determinations. Potential concerns could come from regulated entities, local governments, or water managers worried that the bill could make TMDL determinations more rigid, increase administrative workload, or rely on historical data in ways that affect compliance obligations. Because the bill was postponed indefinitely without recorded dissent, any substantive contention was not reflected in the vote record provided.