Document bBNVObNY2d6jQk4dGyaex2xYD

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595 Wynkoop Street Denver, CO 80202-1129 Phone 800-227-8917 www.epa.gov/region8 October 4, 2023 Ref: 8WD-SDB SENT VIA EMAIL Mr. Jason Murphy, Facilities Supervisor Yellowstone National Park - Mammoth Hot Springs PO Box 168 Yellowstone National Park, Wyoming 82190 jason_murphy@nps.gov Re: Notice of Noncompliance Surface Water Treatment Rule Failure to Report PWS ID# WY5680092 C Dear Jason Murphy: The purpose of this letter is to inform you that Yellowstone National Park - Mammoth Hot Springs public water system (system) failed to report a low chlorine residual to the U.S. Environmental Protection Agency (EPA) in a timely manner. The system reported in the August 2023 monthly operating report submitted to EPA by e-mail on September 10, 2023 that the chlorine residual at the point of entry to the distribution (POE) dropped below 0.2 mg/L on August 28, 2023. Additional documentation submitted to EPA by the system in an e-mail on October 2, 2023 verified that this event was less than 4 hours in duration. Any time the chlorine residual at the POE drops below 0.2 mg/L, the system must notify the EPA as soon as possible, but no later than by the end of the next business day according to 40 C.F.R. 141.75(b)(3)(iii) of the National Primary Drinking Water Regulations (NPDWR). This constitutes a violation of the NPDWR. If not already done, please complete the following actions: (1) Implement a course of action to ensure that the required minimum disinfectant residual is maintained at the point of entry to the distribution system. (2) Set up a communication plan to ensure that the EPA is notified by the end of the next business day when a low chlorine residual at the point of entry occurs. You must also notify the EPA when the residual is restored to above 0.2 mg/L and indicate whether the event lasted more than 4 hours. You should be aware that repeated violations of the National Primary Drinking Water Regulations may result in formal enforcement action taken against your water system. If formal enforcement action were to be necessary, the Safe Drinking Water Act provides for civil penalties of up to $67,544 per day of violation. We prefer to resolve problems before such formal enforcement is necessary and ask your cooperation to rectify problems quickly and effectively. If you have any questions, please contact Jake Crosby at 303-312-6389 or by e-mail at crosby.jake@epa.gov. Sincerely, JUDY BLOOM Digitally signed by JUDY BLOOM Date: 2023.10.04 21:58:58 -06'00' Judy Bloom Supervisor, Drinking Water Section B Water Division cc: Mr. Duane Bubac, Chief of Maintenance Yellowstone National Park duane_bubac@nps.gov Ms. Molly Ohlen, Civil Engineer Yellowstone National Park molly_ohlen@nps.gov