Section 620.310  Preventive Response Activities

a)         The following preventive assessment must be undertaken:

1)         If a preventive notification under Section 620.305(c) is provided by a community water supply:

A)        The Agency shall notify the owner or operator of any identified potential primary source, potential secondary source, potential route, or community water supply well that is located within 2,500 feet of the wellhead.

B)        The owner or operator notified under subsection (a)(1)(A) shall, within 30 days after the date of issuance of such notice, sample each water well or monitoring well for the contaminant identified in the notice if the contaminant or material containing such contaminant is or has been stored, disposed of, or otherwise handled at the site.  If a contaminant identified under Section 620.305(a) is detected, then the well must be resampled within 30 days of the date on which the first sample analyses are received.  If a contaminant identified under Section 620.305(a) is detected by the resampling, preventive notification must be given as set forth in Section 620.305.

C)        If the Agency receives analytical results under subsection (a)(1)(B) that show a contaminant identified under Section 620.305(a) has been detected, the Agency shall:

i)          Conduct a well site survey pursuant to 415 ILCS 5/17.1(d), if such a survey has not been previously conducted within the last 5 years; and

ii)         Identify those sites or activities that represent a hazard to the continued availability of groundwaters for public use unless a groundwater protection needs assessment has been prepared pursuant to 415 ILCS 5/17.1(d).

2)         If a preventive notification is provided under Section 620.305(c) by a non-community water supply or for multiple private water supply wells, the Department of Public Health shall conduct a sanitary survey within 1,000 feet of the wellhead of a non-community water supply or within 500 feet of the wellheads for multiple private water supply wells.

3)         If a preventive notification under Section 620.305(b) is provided by the owner or operator of a regulated entity and the applicable standard in Subpart D has not been exceeded:

A)        The appropriate regulatory agency shall determine if any of the following occurs for Class I:  Potable Resource Groundwater:

i)          The levels set forth below are exceeded or are changed for pH:

ii)         A statistically significant increase occurs above background (as determined pursuant to other regulatory procedures (e.g., 35 Ill. Adm. Code 616, 724, 725 or 811)) for arsenic, beryllium, cadmium, chromium, cyanide, lead, mercury, thallium, or vanadium (except due to natural causes); or for acenaphthene, acetone, aldicarb, anthracene, atrazine, benzoic acid, carbon disulfide, carbofuran, dalapon, 2-butanone (MEK), dicamba, dichlorodifluoromethane, 1,1-dichloroethane, diethyl phthalate, di-n-butyl phthalate, dinoseb, endrin, endothall, fluoranthene, fluorine, hexachlorocyclopentadiene, isopropylbenzene (cumene), lindane (gamma-hexachloro cyclohexane), 2,4-D,1,1 - dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, MCPP (mecoprop), 2-methylnaphthalene, methoxychlor, 2-methylphenol, monochlorobenzene, naphthalene, picloram, pyrene, simazine, 2,4,5-TP (silvex), 1,2,4-trichlorobenzene, 1,1,2-trichloroethane, 1,1,1trichloroethane, and trichlorofluoromethane.

iii)        For a chemical constituent of gasoline, diesel fuel, or heating fuel, the constituent exceeds the following:

iv)        For pH, a statistically significant change occurs from background.

BOARD NOTE:  Constituents that are carcinogens have not been listed in subsection (a)(3)(A) because the standard is set at the PQL and any exceedence thereof is a violation subject to corrective action.

B)        The appropriate agency shall determine if, for Class III:  Special Resource Groundwater, the levels as determined by the Board are exceeded.

C)        The appropriate regulatory agency shall consider whether the owner or operator reasonably demonstrates that:

i)          The contamination is a result of contaminants remaining in groundwater from a prior release for which appropriate action was taken in accordance with laws and regulations in existence at the time of the release;

ii)         The source of contamination is not due to the on-site release of contaminants; or

iii)        The detection resulted from error in sampling, analysis, or evaluation.

D)        The appropriate regulatory agency shall consider actions necessary to minimize the degree and extent of contamination.

b)         The appropriate regulatory agency shall determine whether a preventive response must be undertaken based on relevant factors including, but not limited to, the considerations in subsection (a)(3).

c)         After completion of preventive response pursuant to authority of an appropriate regulatory agency, the concentration of a contaminant listed in subsection (a)(3)(A) in groundwater may exceed 50 percent of the applicable numerical standard in Subpart D only if the following conditions are met:

1)         The exceedence has been minimized to the extent practicable;

2)         Beneficial use, as appropriate for the class of groundwater, has been assured; and

3)         Any threat to public health or the environment has been minimized.

d)         Nothing in this Section shall in any way limit the authority of the State or of the United States to require or perform any corrective action process.

(Source:  Amended at 36 Ill. Reg. 15206, effective October 5, 2012)