MARYLAND DEPARTMENT OF THE ENVIRONMENT WATER AND SCIENCE ADMINISTRATION NOTICE OF TENTATIVE DETERMINATION Washington County Application for State Discharge Permit 24DP2886, NPDES Permit MD0065757: The DIA-LYN Incorporated, 12617 Seavolt Road, Hancock, Maryland 21750, applied for renewal of the permit to discharge an average of 25,000 gallons per day (gpd) of treated domestic wastewater from the Happy Hills Campground Wastewater Treatment Plant, located at 12617 Seavolt Road, Hancock, Maryland 21750, to an unnamed tributary of the Potomac River, which is designated as Use I-P water which is protected for water contact recreation, aquatic life, and as a public water supply. The Department is proposing to reissue the discharge permit with the following effluent limitations: BOD5, 20 mg/l maximum monthly arithmetic mean, 30 mg/l maximum weekly arithmetic mean from May 1 to October 31, 30 mg/l maximum monthly arithmetic mean, 45 mg/l maximum weekly arithmetic mean from November 1 to April 30; total suspended solids, 30 mg/l maximum monthly arithmetic mean, 45 mg/l maximum weekly arithmetic mean; total ammonia nitrogen as N interim limits from May 1 to October 31, 0.8 mg/l maximum monthly arithmetic mean, 6.0 mg/l maximum daily arithmetic mean, from November 1 to April 30, 4.3 mg/l maximum monthly arithmetic mean, 5.1 mg/l maximum daily arithmetic mean for average flows less than 5,000 gpd, from May 1 to October 31, 0.7 mg/l maximum monthly arithmetic mean, 5.0 mg/l maximum daily arithmetic mean, from November 1 to April 30, 1.8 mg/l maximum monthly arithmetic mean, 4.1 mg/l maximum daily arithmetic mean for average flows 5,000 gpd to 25,000 gpd; total ammonia nitrogen as N final limits from May 1 to October 31, 0.4 mg/l maximum monthly arithmetic mean, 1.8 mg/l maximum daily arithmetic mean, from November 1 to April 30, 0.8 mg/l maximum monthly arithmetic mean, 4.2 mg/l maximum daily arithmetic mean for average flows less than 5,000 gpd, from May 1 to October 31, 0.32 mg/l maximum monthly arithmetic mean, 1.3 mg/l maximum daily arithmetic mean, from November 1 to April 30, 0.62 mg/l maximum monthly arithmetic mean, 3.0 mg/l maximum daily arithmetic mean for average flows from 5,000 gpd to 25,000 gpd; E. coli, 126 MPN/100 ml maximum monthly geometric mean; pH maintained between 6.5 and 8.5; dissolved oxygen 5.0 mg/l minimum at any time and total residual chlorine level is limited to 0.11 mg/l maximum at any time if chlorine is used for disinfection. This permit is in conformance with the Chesapeake Bay Total Maximum Daily Load [TMDL] for Nitrogen, Phosphorus, and Sediment established on December 29, 2010. The effluent limits are set to maintain compliance with State water quality standards. Per MD Environmental Article § 1–602(a)(2), an EJ score was calculated for this facility. The EJ Score is 27.7. This score has been calculated considering a combination of the following factors: Pollution Burden Exposure Percentile, Pollution Burden Environmental Effects Percentile, and Sensitive Population Percentile. For more information on how the score was calculated, launch the MDEnviroScreen tool from this website - https://mdewwp.page.link/EJ Copies of the application, draft permit, and Summary Report & Fact Sheet (SRFS) are available on the Department’s Wastewater Permits Interactive Search Portal at https://mdewwp.page.link/WWPPortal. Search for 24DP2886 under “State Num” and click on the “More Info” button for the permit entry to generate a list of available documents for download. If a written request is received by December 2, 2025, a public hearing on the tentative determination for this application can be scheduled. The request should be sent to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Baltimore, Maryland 21230-1708, Attn.: Yen-Der Cheng, Chief, Municipal Permits Division and must include the name, address and telephone number (home and work) of the person making the request, the name of any other party whom the person making the request may represent, and the name of the facility and permit number. Failure to request a hearing by December 2, 2025 will constitute a waiver of the right to a public hearing on the tentative determination for this permit. Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department, to the attention of Yen-Der Cheng at the above address, on or before December 12, 2025. Any hearing-impaired person who requests a hearing may request an interpreter at the hearing by contacting Mr. Cheng at (410) 537-3363 or 1-800-633-6101, or by written request to the above address at least ten working days prior to the scheduled hearing date. Information supporting the tentative determination, including the draft permit and fact sheet, may be reviewed by contacting Mr. Cheng at the above telephone number to make an appointment or by written request to Mr. Cheng at the above address. Copies of documents may be obtained at a cost of $0.36 per page. 11/12, 11/19/25 #11818068