Maryland's Surface Water Quality Standards
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Advance Notice of Public Rulemaking - 2025 Triennial Review of Water Quality Standards
The Department of the Environment is providing an Advanced Notice of Public Rulemaking for the 2025 Triennial Review of Water Quality Standards. This notification provides an early opportunity for public comment on the topics the Department is considering in the next Triennial Review.
For more information, please click here.
September 18, 2024
Updated January 24, 2025 |
Proposed Existing Use Determination and Rationale DocumentsThe Department of the Environment has shared for public review and comment seven (7) proposed cold water existing use determination and rationale documents. The public comment period which opened on September 6, 2024 closed on December 9, 2024. Please visit MDE's Existing Use Determinations webpage for more information. |
The purpose of water quality standards is to protect, maintain and improve the quality of Maryland surface waters. The following make up the three components of water quality standards:
- Designated Uses,
- Water quality criteria, and
- Antidegradation policy.
A designated use is a goal for water quality. Typically, the goal is the description of an appropriate intended use by humans and/or aquatic life for a water body. Designated uses for a particular waterbody may include recreation, shellfishing, water supply and/or aquatic life habitat. The designated uses established may or may not be met currently, but must be attainable. In Maryland these designated uses are grouped into "Use Classes" (e.g. Use Class I, I-P, II, III, IV-P) so as to describe a unique combination of designated uses that apply to a single water body. Each stream segment, lake, bay, etc. in Maryland is assigned to a use class.
For more detailed information about Maryland’s designated uses and use class groupings, please click HERE. To go directly to maps of surface waters and their associated use classes, please click HERE.
Water quality criteria are expressions of the quality of water as a concentration, level, or narrative statement that, if met, will generally protect a particular designated use. Maryland has many numeric criteria for protecting aquatic life and human health including for toxics (e.g., lead), physical characteristics of water (e.g., temperature, dissolved oxygen), bacteriological indicators, and even biological endpoints (e.g., quantity of submerged aquatic vegetation). Where specific numeric criteria are not available (e.g., oil, grease, odor, nuisance), narrative criteria apply.
Maryland’s antidegradation policy and implementation procedures, consistent with the Clean Water Act, provides a framework for maintaining and protecting water quality that has already been achieved. Maryland’s Antidegradation regulations provide for three tiers of protection:
For the full text of Maryland Water Quality Standards please visit COMAR Online to access 26.08.01 and 26.08.02.
Changes to the Water Quality Standards are implemented through regulatory changes which are subject to the normal promulgation process. Every three years, the Clean Water Act requires that States review their water quality standards in what is called the Triennial Review of Water Quality Standards (TR). The TR includes a robust public participation process prior to adoption of new or revised regulations. This process generally includes an Advanced Notice of Public Rule-Making (ANPRM) and solicitation of comments followed later by a more formal public comment period during which a hearing takes place (the formal comment period and hearing are required). Comments are incorporated and/or responded to in what becomes a public document as part of the TR package that EPA reviews. To see materials from Maryland's past Triennial Review actions please click here.
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Contact Information
For more information, please contact Melinda Cutler at melinda.cutler@maryland.gov.
Last Updated 01/2025
