1. (a) The groundwater monitoring program shall include consistent sampling and analysis procedures designed to ensure monitoring results that provide an accurate representation of groundwater quality at the background and downgradient wells required by Section R315-319-91. The owner or operator of the CCR unit shall develop and receive approval from the director for a sampling and analysis program that includes procedures and techniques for:
2. (1) sample collection;
3. (2) sample preservation and shipment;
4. (3) analytical procedures;
5. (4) chain of custody control; and

6. (5) quality assurance and quality control.

   1. (b) The groundwater monitoring program shall include sampling and analytical methods that are appropriate for groundwater sampling and that accurately measure hazardous constituents and other monitoring parameters in groundwater samples. For Sections R315-319-90 through R315-319-98, the term constituent refers to both hazardous constituents and other monitoring parameters listed in either Appendix III or IV to Rule R315-319.
   2. (c) Groundwater elevations shall be measured in each well immediately before purging, each time groundwater is sampled. The owner or operator of the CCR unit shall determine the rate and direction of groundwater flow each time groundwater is sampled. Groundwater elevations in wells that monitor a CCR management area shall be measured within a period short enough to avoid temporal variations in groundwater flow that could preclude accurate determination of groundwater flow rate and direction.
   3. (d) The owner or operator of the CCR unit shall establish background groundwater quality in a hydraulically upgradient or background well for each of the constituents required in the particular groundwater monitoring program that applies to the CCR unit as determined under Subsection R315-319-94(a) or R315-319-95(a). Background groundwater quality may be established at wells that are not located hydraulically upgradient from the CCR unit if it meets the requirements of Subsection R315-319-91(a)(1).
   4. (e) The number of samples collected when conducting detection monitoring and assessment monitoring, for both downgradient and background wells, shall be consistent with the statistical procedures chosen under Subsection R315-319-93(f) and the performance standards under Subsection R315-319-93(g). The sampling procedures shall be those specified under Subsections R315-319-94(b) through R315-319-94(d) for detection monitoring, Subsections R315-319-95(b) through R315-319-95(d) for assessment monitoring, and Subsection R315-319-96(b) for corrective action.
   5. (f) The owner or operator of the CCR unit shall select one of the statistical methods specified in Subsections R315-319-93(f)(1) through R315-319-93(f)(5) to be used in evaluating groundwater monitoring data for each specified constituent. The statistical test chosen shall be conducted separately for each constituent in each monitoring well.
7. (1) A parametric analysis of variance followed by multiple comparison procedures to identify statistically significant evidence of contamination. The method shall include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent.
8. (2) An analysis of variance based on ranks followed by multiple comparison procedures to identify statistically significant evidence of contamination. The method shall include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent.
9. (3) A tolerance or prediction interval procedure, in which an interval for each constituent is established from the distribution of the background data and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit.
10. (4) A control chart approach that gives control limits for each constituent.
11. (5) Another statistical test method that meets the performance standards of Subsection R315-319-93(g) and has been approved by the director.

12. (6) The owner or operator of the CCR unit shall get a certification from a qualified professional engineer stating that the selected statistical method is appropriate for evaluating the groundwater monitoring data for the CCR management area. The certification shall include a narrative description of the statistical method selected to evaluate the groundwater monitoring data.

    1. (g) Any statistical method chosen under Subsection R315-319-93(f) shall comply with the performance standards listed in Subsections R315-319-93(g)(1) through R315-319-93(g)(6), as appropriate, based on the statistical test method used:
13. (1) The statistical method used to evaluate groundwater monitoring data shall be appropriate for the distribution of constituents. Normal distributions of data values shall use parametric methods. Non-normal distributions shall use non-parametric methods. If the distribution of the constituents is shown by the owner or operator of the CCR unit to be inappropriate for a normal theory test, then the data shall be transformed or a distribution-free, non-parametric, theory test shall be used. If the distributions for the constituents differ, more than one statistical method may be needed.
14. (2) If an individual well comparison procedure is used to compare an individual compliance well constituent concentration with background constituent concentrations or a groundwater protection standard, the test shall be done at a Type I error level no less than 0.01 for each testing period. If a multiple comparison procedure is used, the Type I experiment wise error rate for each testing period shall be no less than 0.05; however, the Type I error of no less than 0.01 for individual well comparisons shall be maintained. This performance standard does not apply to tolerance intervals, prediction intervals, or control charts.
15. (3) If a control chart approach is used to evaluate groundwater monitoring data, the specific type of control chart and its associated parameter values shall be such that this approach is at least as effective as any other approach in Section R315-319-93 for evaluating groundwater data. The parameter values shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.

16. (4) If a tolerance interval or a predictional interval is used to evaluate groundwater monitoring data, the levels of confidence and, for tolerance intervals, the percentage of the population that the interval shall contain, shall be such that this approach is at least as effective as any other approach in Section R315-319-93 for evaluating groundwater data. These

    parameters shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.

17. (5) The statistical method shall account for data below the limit of detection with one or more statistical procedures that shall at least as effective as any other approach in Section R315-319-93 for evaluating groundwater data. Any practical quantitation limit that is used in the statistical method shall be the lowest concentration level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions that are available to the facility.

18. (6) If necessary, the statistical method shall include procedures to control or correct for seasonal and spatial variability as well as temporal correlation in the data.

    1. (h) The owner or operator of the CCR unit shall determine whether or not there is a statistically significant increase over background values for each constituent required in the particular groundwater monitoring program that applies to the CCR unit, as determined under Subsection R315-319-94(a) or R315-319-95(a).
19. (1) In determining whether a statistically significant increase has occurred, the owner or operator shall compare the groundwater quality of each constituent at each monitoring well designated pursuant to Subsection R315-319-91(a)(2) or R315-319-91(d)(1) to the background value of that constituent, according to the statistical procedures and performance standards specified under Subsections R315-319-93(f) and R315-319-93(g).

20. (2) Within 90 days after completing sampling and analysis, the owner or operator shall determine whether there has been a statistically significant increase over background for any constituent at each monitoring well.

    1. (i) The owner or operator shall measure total recoverable metals concentrations in measuring groundwater quality. Measurement of total recoverable metals captures both the particulate fraction and dissolved fraction of metals in natural waters. Groundwater samples may not be field-filtered before analysis.

    2. (j) The owner or operator of the CCR unit shall comply with the recordkeeping requirements specified in Subsection R315-319-105(h), the notification requirements specified in Subsection R315-319-106(h), and the internet requirements specified in Subsection R315-319-107(h).

       R315-319-94 Groundwater Monitoring and Corrective Action - Detection Monitoring Program.

    3. (a) The owner or operator of a CCR unit shall conduct detection monitoring at each groundwater monitoring well consistent with Section R315-319-94. At a minimum, a detection monitoring program shall include groundwater monitoring for the constituents listed in Appendix III to Rule R315-319.
    4. (b) Except as provided in Subsection R315-319-94(d), the monitoring frequency for the constituents listed in Appendix III to Rule R315-319 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 III and Appendix IV to Rule R315-319 no later than October 17, 2017. For new CCR landfills, new CCR surface impoundments, and 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 Appendices III and IV to Rule R315-319 during the first six months of sampling.
    5. (c) The number of samples collected and analyzed for each background well and downgradient well during subsequent semiannual sampling events shall be consistent with Subsection R315-319-93(e), and shall account for any unique characteristics of the site, but shall be at least one sample from each background and downgradient well.
    6. (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 III to Rule R315-319 during the active life and the post-closure care period based on the availability of groundwater. This demonstration shall be submitted and approved by the director. 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 Subsections R315-319-94(d)(1) and R315-319-94(d)(2).

21. (1) Information documenting that the need for less frequent sampling. The alternative frequency shall be based on consideration of the factors listed in Subsections R315-319-94(d)(1)(i) through R315-319-94(d)(1)(iii):

    1. (i) lithology of the aquifer and unsaturated zone;

       1. (ii) hydraulic conductivity of the aquifer and unsaturated zone; and
       2. (iii) groundwater flow rates.
22. (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.

23. (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 Section R315-319-94. 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 Subsection R315-319-90(e).

    1. (e) If the owner or operator of the CCR unit determines, pursuant to Subsection R315-319-93(h) that there is a statistically significant increase over background levels for one or more of the constituents listed in Appendix III to Rule R315-319 at any monitoring well at the waste boundary specified under Subsection R315-319-91(a)(2), the owner or operator shall:
24. (1) Except as provided for in Subsection R315-319-94(e)(2), within 90 days of detecting a statistically significant increase over background levels for any constituent, establish an assessment monitoring program meeting the requirements of Section R315-319-95.
25. (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 90 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 90-day period, the owner or operator of the CCR unit may continue with a detection monitoring program under Section R315-319-94. If a successful demonstration is not completed within the 90-day period, the owner or operator of the CCR unit shall initiate an assessment monitoring program as required under Section R315-319-95. The owner or operator shall also include the demonstration in the annual groundwater monitoring and corrective action report required by Subsection R315-319-90(e), in addition to the certification by a qualified professional engineer.

26. (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 Subsection R315-319-105(h)(5).

    1. (f) The owner or operator of the CCR unit shall comply with the recordkeeping requirements specified in Subsection R315-319-105(h), the notification requirements specified in Subsection R315-319-106(h), and the internet requirements specified in Subsection R315-319-107(h).

KEY: permit, solid waste, coal ash

Date of Last Change: September 15, 2025

Notice of Continuation: June 16, 2026

Authorizing, and Implemented or Interpreted Law: 19-6-108