may come prepared with their own water bottles. (J) Input from the National Park Service Office of Public Health. (K) The feasibility of posting signs so that visitors can easily find bottle refill stations. (L) Safety considerations for visitors who may resort to not carrying enough water or drinking from surface water sources with potential exposure to disease. (M) Any input from concessioners and cooperating associations within the relevant unit. (2) Units of NPS previously eliminated sale of water in disposable plastic products With respect to a unit of the National Park System that did not offer for sale water in disposable plastic products before the date of the enactment of this Act, the applicable superintendent of the relevant unit may continue to not offer for sale water in disposable plastic bottles. (c) Proactive visitor education strategy Each regional director concerned shall develop for the relevant unit of the National Park System a proactive visitor education strategy to address visitor expectations of water availability and explain the rationale for the program and its implementation in the relevant unit. (d) Continuity within unit of the NPS Each regional director concerned shall, to the extent possible, implement the program in a manner that is consistent throughout the relevant unit of the National Park System, including incorporation of such program into any agreement with an organization operating within the relevant unit, including a concessioner operating plan and cooperating association scope of sales. (e) Biennial evaluation Each regional director concerned shall, not less than once every 2 years— (1) conduct an evaluation of the program for the relevant unit of the National Park System, including— (A) public response to the program