Rule 3745-525-930 | Detection monitoring program, 40 C.F.R. 257.94.
(A) The owner or operator of a CCR unit shall conduct detection monitoring at all groundwater monitoring wells consistent with this rule. At a minimum, a detection monitoring program shall include groundwater monitoring for all constituents listed in appendix A to rule 3745-525-900 of the Administrative Code.
(B) Except as provided in paragraph (D) of this rule, the monitoring frequency for the constituents listed in appendix A to rule 3745-525-900 of the Administrative Code shall be at least semiannual during the active life of the CCR unit and the post-closure period. For existing CCR landfills and existing CCR surface impoundments, a minimum of eight independent samples from each background and downgradient well shall be collected and analyzed for the constituents listed in appendix A and B to rule 3745-525-900 of the Administrative Code not later than October 17, 2017. For new CCR landfills, new CCR surface impoundments, and all lateral expansions of CCR units, a minimum of eight independent samples for each background well shall be collected and analyzed for the constituents listed in appendix A and appendix B to rule 3745-525-900 of the Administrative Code during the first six months of sampling.
(C) The number of samples collected and analyzed for each background well and downgradient well during subsequent semiannual sampling events shall be consistent with paragraph (E) of rule 3745-525-920 of the Administrative Code, and shall account for any unique characteristics of the site, but shall be at least one sample from each background and downgradient well.
(D) The owner or operator of a CCR unit may demonstrate the need for an alternative monitoring frequency for repeated sampling and analysis for constituents listed in appendix A to rule 3745-525-900 of the Administrative Code during the active life and the post-closure care period based on the availability of groundwater. If there is not adequate groundwater flow to sample wells semiannually, the alternative frequency shall be no less than annual. The need to vary monitoring frequency shall be evaluated on a site-specific basis. The demonstration shall be supported by, at a minimum, the information specified in paragraphs (D)(1) and (D)(2) of this rule.
(1) Information documenting the need for less frequent sampling. The alternative frequency shall be based on consideration of the following factors:
(a) Lithology of the aquifer and unsaturated zone.
(b) Hydraulic conductivity of the aquifer and unsaturated zone.
(c) Groundwater flow rates.
(2) Information documenting that the alternative frequency will be no less effective in ensuring that any leakage from the CCR unit will be discovered within a timeframe that will not materially delay establishment of an assessment monitoring program.
(3) The owner or operator shall obtain a certification from a qualified professional engineer stating that the demonstration for an alternative groundwater sampling and analysis frequency meets the requirements of this rule. The owner or operator shall include the demonstration providing the basis for the alternative monitoring frequency and the certification by a qualified professional engineer in the annual groundwater monitoring and corrective action report required by paragraph (E) of rule 3745-525-900 of the Administrative Code.
(E) If the owner or operator of the CCR unit determines, pursuant to paragraph (H) of rule 3745-525-920 of the Administrative Code that there is a statistically significant increase over background levels for one or more of the constituents listed in appendix A to rule 3745-525-900 of the Administrative Code at any monitoring well at the waste boundary specified under paragraph (A)(2) of rule 3745-525-910 of the Administrative Code, the owner or operator shall do the following:
(1) Except as provided for in paragraph (E)(2) of this rule, within ninety days of detecting a statistically significant increase over background levels for any constituent, establish an assessment monitoring program meeting the requirements of rule 3745-525-940 of the Administrative Code.
(2) The owner or operator may demonstrate that a source other than the CCR unit caused the statistically significant increase over background levels for a constituent or that the statistically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in groundwater quality. The owner or operator shall complete the written demonstration within ninety days of detecting a statistically significant increase over background levels to include obtaining a certification from a qualified professional engineer verifying the accuracy of the information in the report. If a successful demonstration is completed within the ninety-day period, the owner or operator of the CCR unit may continue with a detection monitoring program under this rule. If a successful demonstration is not completed within the ninety-day period, the owner or operator of the CCR unit shall initiate an assessment monitoring program as required under rule 3745-525-940 of the Administrative Code. The owner or operator shall also include the demonstration in the annual groundwater monitoring and corrective action report required by paragraph (E) of rule 3745-525-900 of the Administrative Code, in addition to the certification by a qualified professional engineer.
(3) The owner or operator of a CCR unit shall prepare a notification stating that an assessment monitoring program has been established. The owner or operator has completed the notification when the notification is placed in the facility's operating record as required by paragraph (H)(5) of rule 3745-525-50 of the Administrative Code.
(F) The owner or operator of the CCR unit shall comply with the recordkeeping requirements specified in paragraph (H) of rule 3745-525-50 of the Administrative Code, the notification requirements specified in paragraph (H) of rule 3745-525-60 of the Administrative Code, and the internet requirements specified in paragraph (H) of rule 3745-525-70 of the Administrative Code.
Last updated October 1, 2026 at 9:52 AM
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