Clean Water Act/Draft 2024-2026 Section 303(d) Impaired Waters List: Missouri Department of Natural Resources Public Notice

The Missouri Department of Natural Resources (“MRNR”) issued its Draft Missouri 2024-2026 Section 303(d) Impaired Waters List.

MDNR states that it has included prioritizing waters for Total Maximum Daily Load (TMDL) development as part of Missouri's proposed 2024-2026 Section 303(d) Impaired Waters List. 

Section 303 of the Clean Water Act requires that each state develop Water Quality Standards (“WQS”)  for jurisdictional Waters of the United States within their borders. WQS serve a dual purpose. They establish the water quality goals for a specific waterbody and also serve as a regulatory basis for the development of water quality-based effluent limits and strategies for individual point sources.

A WQS consists of three parts:

1. The designated uses of a waterbody;
2. The Water Quality Criteria (“WQC”) that are necessary to protect existing uses and to attain the beneficial uses designated by the state; and
3. An antidegradation statement or policy to protect existing uses and high-quality water.

Each state must adopt uses consistent with the Clean Water Act objectives and WQC sufficient to protect the chosen uses. However, EPA is required to ensure that state WQS, along with any changes, meet the minimum requirements of the Clean Water Act.

EPA will assess whether the WQS protect state criteria and/or designated uses taking into the account the water’s use and value for public water supplies, propagation of fish and wildlife, recreational purposes, and agricultural, industrial, navigation, and other purposes. The Clean Water Act regulations provide for EPA review of any state WQS changes.

Section 303 of the Clean Water Act also requires each state to identify those waters within its boundaries for which the technology-based effluent limitations required by the Clean Water Act and defined by EPA are not stringent enough to attain applicable WQS. Water so designated are known as “Water Quality Limited Segments” or “Impaired Waters”. Each state is required to submit this list of waters to EPA biennially (accompanied by a listing determination).

MDNR states it will hold a public hearing on the Draft Impaired Waters List on October 27th from 10:00 AM until noon in the Lewis and Clark State Office Building in Jefferson City, Missouri.

Additional public hearings are scheduled as outlined below:

• Public Meeting-Aug. 15, 2025
• Public Meeting-Sept. 19, 2025
• Public Meeting-Oct. 6, 2025

A copy of the public notice that contains a link to the Draft Impaired Waters List can be found here.