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Water Quality

The Division of Water Quality (DWQ) includes several programs to protect and manage clean water and public health. The water quality program implements portions of the Pennsylvania Clean Streams Law (P.L 1987, Act 394 of 1937, as amended (35 P.S. §§ 691.1 et seq.)) and the federal Clean Water Act (33 U.S.C. §1251 et seq. (1972)).

Water quality standards are used to assess whether Pennsylvania's rivers and lakes are clean and pure enough to support fish and other aquatic life; recreation; water supply for drinking, agriculture, and industry; and other protected uses. In addition, the water standards are implemented by other BCW programs as regulatory tools to prevent pollution of the Commonwealth's waters.

The DWQ programs to protect clean water include:

  • Standards Section - responsible for developing and establishing the water criteria and protected uses that surface waters must meet
  • Monitoring Section - responsible for designing and implementing surface water monitoring for water chemistry, biology (invertebrates, fishes, algae, plants and pathogens), and physical habitat
  • Assessment Section - responsible for developing and implementing protocols to analyze and evaluate monitoring data to determine surface water attainment of water standards
  • Total Maximum Daily Load (TMDL) Development Section - responsible for modeling and setting pollution loads that will allow impaired waters to meet water standards

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The Standards Section coordinates activities involving the development, review, and maintenance of statewide and site-specific water quality standards, and develops rulemaking in support of triennial review of water quality standards and stream redesignations. It coordinates federal Clean Water Act Section 316 activities to ensure compliance with program directives, and activities involving the review, implementation, and development of the Antidegradation Policy and directives.

The section coordinates and oversees activities in support of the Interagency Fish Tissue Consumption Advisory program; maintains and updates relevant regulations, policy statements, guidance documents, and data systems to implement water quality standards directives and goals; and provides representation on inter- and intra-state commissions, committees, boards, workgroups, and taskforces in support of water quality program directives and goals.


The Monitoring Section coordinates the Statewide Surface Water Quality Monitoring Program for the purpose of assessing the Commonwealth's protected water uses. This includes monitoring for aquatic life, water supply, recreation, fish consumption, and special protection.

The section also provides Fish Consumption Advisories, which are the basis of the fish consumption impairments found in the Integrated Report.


The Assessment Section is responsible for analyzing available monitoring data, both internal to DEP and from outside sources (watershed organizations; other state, local and federal agencies; river basin commissions; etc.), to determine the attainment of surface water standards.

The section has developed assessment methods for benthic macroinvertebrates, fishes, pathogens and water chemistry, which are included in the Assessment Methodology. These assessment methods are used for the biennial Pennsylvania Integrated Water Quality Monitoring and Assessment Report (Integrated Report). The Integrated Report is submitted to EPA, and is composed of the CWA Section 305(b) report of the water quality status of all surface waters and the Section 303(d) list of impaired waters. The Pennsylvania Integrated Water Quality Monitoring and Assessment Report was approved by EPA on January 10, 2018.


The TMDL Development Section is responsible for the statewide establishment of Total Maximum Daily Loads (TMDLs) developed to address waterbody impairments identified in the Pennsylvania Integrated Water Quality Monitoring and Assessment Report (Integrated Report).

The TMDL Development Section also assists in the resolution of issues related to the implementation of previously approved TMDLs.

Additionally, the TMDL Development Section has the lead in the development of numeric criteria for nutrients, and an objective/quantitative protocol for the identification of nutrient related impairments.

The Turtle Creek story is an example of implementation of a sediment TMDL through partnership with local stakeholders.