1. (a) Criteria development. The Department will consider a request for site-specific criteria, or the Department may develop site-specific criteria on its own initiative, when one or more of the following apply:

   1. (1) There exist site-specific biological or chemical conditions of the waterbody or waterbody segment which differ from conditions upon which the aquatic life water quality criteria were based.
   2. (2) More stringent criteria are needed for a pollutant listed in § 93.7, Table 3 (relating to specific water quality criteria) or § 93.8c, Table 5 (relating to human health and aquatic life criteria for toxic substances) regarding water quality criteria for toxic substances to protect more sensitive, intervening uses.
   3. (3) There exists a need for a site-specific criterion for a pollutant not listed in § 93.7, Table 3 or § 93.8c, Table 5.

   4. (4) There exists a need for a site-specific criterion for a pollutant to address a cause of impairment for a protected water use, as listed in Pennsylvania’s Integrated Water Quality Monitoring and Assessment Report, as amended and updated.

      (a.1) Restrictions. Site-specific criteria may not be developed for surface waters with an existing or designated use of High Quality Waters or Exceptional Value Waters.

2. (b) Demonstration. The applicant’s demonstration for consideration of site-specific criteria, under subsections (a) and (a.1), shall include the following information, at a minimum:

   1. (1) {Reserved}.

      (1.1) Identification of the pollutant of concern.

   2. (2) {Reserved}.

      (2.1) Identification of the qualifying factor or factors in subsection (a).

   3. (3) Identification of each waterbody or waterbody segment to which the site-specific criteria would apply, including stream name, municipality or municipalities, county or counties and existing and designated uses of each waterbody or waterbody segment.

   4. (4) Scientific studies, data or other information that demonstrate the qualifying factor or factors in subsection (a) are met, which may include the following:

      1. (i) Peer-reviewed, scientific literature related to the pollutant of concern.

      2. (ii) For a demonstration of the qualifying factor in subsection (a)(1):

         1. (A) Department or Federal water quality criteria rationale documents and regulations related to the pollutant of concern.
         2. (B) Water quality and other relevant data collected on each waterbody or waterbody segment which demonstrate that the conditions differ from conditions upon which the existing aquatic life water quality criteria were based.

      3. (iii) For a demonstration of the qualifying factor in subsection (a)(2):

         1. (A) Documentation of more sensitive, intervening water uses for each waterbody or waterbody segment.
         2. (B) Documentation of the presence, critical habitat or critical dependence of Federally-listed or State-listed threatened or endangered species in or on a surface water, if applicable.
      4. (iv) Additional data or information as requested by the Department or that demonstrates the applicable qualifying factor is met.
   5. (5) Information that demonstrates subsection (a.1) is not applicable.
   6. (6) Information that demonstrates a water quality-based effluent limitation based on a water quality criterion found in § 93.7, Table 3 or § 93.8c, Table 5 is not achievable.

3. (c) Additional information. Based on the results of a demonstration that the request for site-specific criteria satisfies subsections (a), (a.1) and (b), the Department may require the applicant to undertake studies and submit additional information to develop site-specific criteria that includes the following, at a minimum:

   1. (1) Definition of the areal boundaries for application of the site-specific criteria which will include a description of each waterbody or waterbody segment.
   2. (2) Identification of potentially affected National Pollutant Discharge Elimination System (NPDES)-permitted discharges, water withdrawals, total maximum daily loads (TMDL) and surface water assessments.
   3. (3) Peer-reviewed scientific literature or other Department-approved data to be used in the development of the site-specific criterion. If data will be collected, a copy of the proposed plan for data collection shall be submitted for review, consideration and approval by the Department prior to commencement of data collection. Data collection shall be completed in accordance with the Department’s data collection protocols and the following procedures and guidance, as amended and updated: Water Quality Standards Handbook (EPA 1994), ‘‘Guidance on the Determination and Use of Water-Effect Ratios for Metals’’ (February 1994); the ‘‘Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health’’ (2000) and the ‘‘Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses’’ (1985). Other guidance approved by the Department, which is based on EPA-approved or scientifically defensible methodologies, may be used. The development of new or updated site-specific criteria for copper in freshwater systems shall be performed using the biotic ligand model (BLM).
   4. (4) Copies of reports, including toxicity test data, signed by the consultant or entity that performed the work. Signed copies shall be submitted to the Department within 60 days of completion of the tests.

   5. (5) Additional data or information as requested by the Department.

      (c.1) Department evaluation. If the required data and information is submitted, the Department will evaluate the information and may develop site-specific criteria for each requested waterbody or waterbody segment that protect the existing and designated uses of the surface waters in accordance with the criteria development methodologies outlined in subsection (c)(3), or other EPA-approved guidance and methods.

      (c.2) Procedures. The Department will incorporate approved site-specific criteria into this chapter through rulemaking, after satisfying 40 CFR Part 25 and 40 CFR 131.20(b) (relating to public participation in programs under the Resource Conservation and Recovery Act, the Safe Drinking Water Act, and the Clean Water Act; and state review and revision of water quality standards), and maintain a publicly available table of EPA-approved site-specific criteria.

      (c.3) EPA criteria approval. Site-specific criteria are not effective for Clean Water Act purposes until approved by the EPA.

4. (d) {Reserved}.
5. (e) {Reserved}.
6. (f) {Reserved}.
7. (g) {Reserved}.
8. (h) Burden of proof. A person challenging a Department action under this section shall have the burden of proof to demonstrate that the Department’s action does not meet the requirements of this section.

Authority

The provisions of this § 93.8d amended under sections 5(b)(1) and 402 of The Clean Streams Law (35 P.S. § § 691.5(b)(1) and 691.402); and section 1920-A of The Administrative Code of 1929 (71 P.S. § 510-20).

Source

The provisions of this § 93.8d adopted May 15, 2009, effective May 16, 2009, 39 Pa.B. 2523; amended July 19, 2013, effective July 20, 2013, 43 Pa.B. 4080; amended July 10, 2020, effective July 11, 2020, 50 Pa.B. 3426; amended August 8, 2025, effective August 9, 2025, 55 Pa.B. 5658. Immediately preceding text appears at serial pages (401862) to (401864).

Cross References

This section cited in 25 Pa. Code § 16.24 (relating to metals criteria); 25 Pa. Code § 16.41 (relating to changes and additions); and 25 Pa. Code § 93.8a (relating to toxic substances).