Section Env-Ws 381.10 - Department Evaluation, Approval, and Designation of Optimal Corrosion Control Treatment(a) Having considered available information including, where applicable, studies performed under Env-Ws 381.09(d) through (i) and a system's recommended treatment alternative, the department shall: (1) Approve the corrosion control treatment option recommended by the system owner if the treatment option recommended meets the lead and copper action levels as specified in Env-Ws 381.03; or(2) Specify alternative corrosion control treatment(s) from among those listed in Env-Ws 381.09(d) if the treatment option recommended by the system owner fails to meet the lead action levels as specified in Env-Ws 381.03.(b) When specifying alternative corrosion control treatment, the department shall consider the following: (1) The effects that the alternative corrosion control treatment will have on the water quality parameters specified in Env-Ws 381.09(f) and other water treatment process as listed in Env-Ws 381.09; and(2) The certified operator grade level required to operate the system as specified in Env-Ws 367.(3) The certified operator grade level required to operate the system as specified in Env-Ws 367; and(4) The operational and maintenance costs.(c) The department shall notify the system owner of its decision on optimal corrosion control treatment in writing and explain the basis for this determination. When the department requests additional information to aid its review, the water system owner shall provide the information.(d) Each system owner shall properly install and operate throughout the distribution system the optimal corrosion control treatment specified by the department under (a) through (c) above.(e) The department shall evaluate the results of all lead and copper tap samples and water quality parameter samples submitted by the water system owner and determine whether the system has properly installed and operated the optimal corrosion control treatment specified by the department in (a) through (c) above.(f) Upon reviewing the results of tap water and water quality parameter monitoring by the system, both before and after the system installs optimal corrosion control treatment, the department shall specify: (1) A minimum value or a range of values for pH measured at each entry point to the distribution system;(2) A minimum pH value, measured in all tap samples;(3) The pH value shall be equal to or greater than 7.0, unless the department determines that meeting a pH level of 7.0 is not technologically feasible or is not necessary for the system to optimize corrosion control;(4) If a corrosion inhibitor is used, a minimum concentration or a range of concentrations for the inhibitor, measured at each entry point to the distribution system and in all tap samples, that the department determines is necessary to form a protective film on the interior walls of the pipes of the distribution system;(5) If alkalinity is adjusted as part of optimal corrosion control treatment, a minimum concentration or a range of concentrations for alkalinity, measured at each entry point to the distribution system and in all tap samples; and(6) If calcium carbonate stabilization is used as part of corrosion control, a minimum concentration or a range of concentrations for calcium, measured in all tap samples.(g) The values for the applicable water quality control parameters listed above shall be those that the department determines to reflect optimal corrosion control treatment for the system.(h) T he department shall specify values for additional water quality control parameters determined by the department to reflect optimal corrosion control for the system and the department shall notify the system owner in writing of these determinations and explain the basis for its decisions.(i) The owner of a system using corrosion control shall continue to operate and maintain optimal corrosion control treatment, including maintaining water quality parameters at or above minimum values or within ranges specified by the department as specified in (f) above for all samples collected under Env-Ws 381.19 through Env-Ws 381.21.(j) Compliance with the requirements of this section shall be determined every 6 months pursuant to Env-Ws 381.2 6.(k) A water system shall be out of compliance with the requirements of this section for a 6-month period if it has excursions for any department-specified parameter on more than 9 days during the period.(l) The daily value, when determining if a system has an excursion, shall be calculated as follows:(1) On days when more than one measurement for a water quality parameter is collected at a sampling location, the daily value shall be the average of all results collected during that day regardless of whether they are collected through continuous monitoring, grab sampling, or both;(2) On days when only one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the result of that measurement; and(3) On days when no measurement is collected for the water quality parameter at the sampling location, the daily value shall be the daily value calculated on the most recent day on which the water quality parameter was measured at the sample site.(m) The department shall not use the results in (l) above if the department determines that the data collected is from an obvious sampling error or from known errors in collection, processing, or transcription.(n) A system owner may submit to the department a written request to modify the department's determination of the optimal corrosion control treatment under (a) through (c) above or optimal water quality control parameters under (e) and (f) above.(o) The written request for modification pursuant to (n) above shall include: (2) The system EPA identification number;(3) A detailed explanation as to why the modification is appropriate; and(4) Any supporting documentation to support the rationale of the request.(p) The department shall respond to the modification request in writing and shall approve the modification if the alternative corrosion control treatment proposed continues to optimize corrosion control treatment.(q) In approving the request, the department shall: (1) Set forth any new treatment technique requirements;(2) Explain the basis for its decision; and(3) Provide an implementation schedule for completing the treatment modifications.N.H. Admin. Code § Env-Ws 381.10
(See Revision Note at chapter heading for Env-Ws 300) #6521, eff 6-4-97, ss by #7734, eff 8-2-02; amd by #8351, eff 5-14-05; amd by #9598, eff 11-21-09