TMDL Alternative

Category 4b (TMDL Alternative)

Communities do not have to wait for a formal TMDL planning process. Municipalities can take the initiative to voluntarily create programs to clean up impaired waters. Because these programs are locally controlled, there is an opportunity to reduce overall costs and allows for greater control over the cleanup process.

Impaired waters with pollution control programs in place that are expected to solve pollution problems (i.e., meet water quality standards) are commonly referred to as “Category 4b” waters because they are moved from Category 5 (impaired and needs TMDL) of the State’s Integrated Report to Category 4b (impaired but TMDL not required). While pollution control programs are not TMDLs, they must have many of the same features, and there must be some legal or financial assurance that they will be implemented.

A Category 4b demonstration allows DWR and EPA to formally recognize actions that, from a local perspective, provide a more appropriate and effective response to impairment than TMDL development. DWR has developed guidance for communities interested in developing a plan to address impaired waters. The guidance describes the elements required to qualify for Category 4b. Communities interested in pursuing this option should review the guidance document and plan to meet with DWR’s Modeling and Assessment Branch prior to development. Some communities may find that they are already meeting most if not all of the required elements....