Louisiana Water Quality Regulations and Standards

Louisiana's water quality regulations and standards are designed to 1) provide for the protection and preservation of the abundant natural resources of Louisiana's many and varied aquatic ecosystems; 2) protect the public health and welfare that might otherwise be threatened by degradation of water quality; 3) protect or enhance the quality of state waters for designated uses; and 4) serve the objectives of the Louisiana Water Control Law and Federal Clean Water Act.
 
  • Louisiana Water Quality Regulations and Standards - Louisiana's Water Quality Regulations can be found at the link for Part IX: Water Quality, with Louisiana's Surface Water Quality Standards found in Chapter 11 of the document.
     

    Recent Rulemaking

  • WQ114 – Freshwater Ammonia Aquatic Life Criteria. This Rule adopted and clarified the applicability of freshwater ammonia criteria.  LDEQ adopted a performance-based approach that provides protection of water quality when mussels are either absent or present. Criteria are expressed in the form of a formula, in which temperature and pH are input to calculate the ammonia criterion. 
  • WQ111 – Water Quality Standards Triennial Revision. This Rule corrected typographical errors throughout Chapter 11 in the water quality regulations, updated verbiage in §1109 and §1113 as a result of the Water Quality Management Plan, Volume 3 update in July 2022, removed the implication that numeric criteria may be adopted based on absence of data, corrected errors in Table 1 of §1113 and Table 3 of §1123, as well as revised subsegment boundaries.
  • WQ108 – Post-WQ097 Cleanup Rule. This Rule clarified items found late in the rulemaking process of WQ097, including a deleted “use”, and extraneous “are” and two inaccurate subsegment boundary descriptions.
  • WQ106 – Cross Lake and Cross Bayou Stream Descriptions. This Rule was necessary so that tributaries in the Louisiana portion of the Cross Lake watershed have the "drinking water supply" designation applied.
  • WQ103 – Wilson Slough and Bradley Slough Turbidity Criteria Revisions. This Rule revised the turbidity criteria for two subsegments in the Pearl River Basin (PRB) from 25 nephelometric turbidity units (NTU) to a more appropriate turbidity criteria of 50 NTU.
  • WQ101 – Bayou Chene DO Criterion revision. This Rule classified subsegment 050603 (Bayou Chene-From headwaters to Lacassine Bayou; includes Bayou Grand Marais) as naturally dystrophic waters with a seasonal dissolved oxygen criteria of 5 mg/L December-February and 3 mg/L March-November.
  • WQ097 – Water Quality Standards Revision. This Rule corrected typographical errors, incorrect spelling and incorrect references throughout Chapter 11 in the water quality regulations, added ammonia criterion for freshwater, and revised subsegment descriptions and boundaries using up-to-date technology.
LDEQ Secretary Courtney J. Burdette
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