Remediation Standard Regulations
An Environmental Program Fact Sheet

What are the RSRs?
Connecticut's Remediation Standard Regulations (RSRs) provide detailed guidance and standards that may be used at any site to determine whether or not remediation of contamination is necessary to protect human health and the environment.  The RSRs do not create, in and of themselves, a requirement that remediation be undertaken, nor do they specify a time-frame for completing remediation.
When do the RSRs apply?
Generally, the RSRs apply to any action taken to remediate polluted soil, surface water, or a groundwater plume at or emanating from a release area, provided the remedial action is required pursuant to Chapter 445 or 446k of the Connecticut General Statutes (CGS), or Section 22a-208a(c)(2) of the CGS.
Authorizing Regulation
Sections 22a-133k-1 through 22a-133k-3 of the Regulations of Connecticut State Agencies (RCSA), adopted January 1, 1996 and amended on June 27, 2013 and February 16, 2021.
Remediation Criteria
The RSRs contain criteria for the remediation of soil and groundwater.  The plan for remediation of a polluted property must consider the criteria for both these environmental media.  Factors that may affect the degree of remediation at a polluted site include the groundwater quality classification of the site, the land use of the site, and proximity of sensitive receptors to the contamination.
Soil Remediation
There are two criteria for soil remediation, the Direct Exposure Criteria and the Pollutant Mobility Criteria.
Direct Exposure Criteria are established to protect human health from exposure to contaminants in soil.  With some exceptions, these criteria apply to soil located within fifteen feet of the ground surface.  Polluted soil must be remediated to a concentration that is consistent with the Residential Direct Exposure Criteria, unless the site is used exclusively for industrial or commercial purposes.  In such a case, the less stringent Industrial/Commercial Direct Exposure Criteria may be used, provided an Environmental Use Restriction is recorded to ensure that the site is not used for residential purposes in the future.

Pollutant Mobility Criteria
are established to prevent the pollution of groundwater caused by soil contamination that is available to migrate into groundwater.  The Pollutant Mobility Criteria apply to soil above either the seasonal low or high water table, depending on the groundwater quality classification of the site.  The RSRs also specify when an alternative Pollutant Mobility Criteria is appropriate.  The RSRs include a compliance option using groundwater quality.
The RSRs also specify circumstances in which the Pollutant Mobility Criteria do not apply.  In general, these circumstances include cases where: polluted soil is located beneath a building, provided an Environmental Use Restriction is recorded to prohibit the building from being intentionally destroyed; widespread polluted fill exists, provided the groundwater in the subject area is not used for drinking water purposes; or an engineered control, such as an engineered cap, has been constructed to prevent the contamination of underlying groundwater.
Groundwater Remediation
The goals of groundwater remediation include:
  • Protecting human health
  • Preserving high quality groundwater

  • Protecting existing uses of groundwater
  • Preventing further degradation of groundwater quality
  • Preventing degradation of surface water from discharges of contaminated groundwater
Three criteria apply to the remediation of a groundwater plume. These criteria include Groundwater Protection Criteria, Surface Water Protection Criteria, and Volatilization Criteria.
Groundwater Protection Criteria require that groundwater plumes in high quality groundwater areas be remediated to background quality, or, in certain instances, to levels that adequately protect existing and future uses of groundwater as public or private drinking water supplies.  In areas that have been classified as having degraded groundwater quality due to historical land use practices, the groundwater must be remediated to adequately protect any existing use of groundwater.  The RSRs also specify circumstances in which exemptions or variances from the Groundwater Protection Criteria are appropriate.
Surface Water Protection Criteria apply to a groundwater plume at the point where the plume discharges to a surface water body. These criteria are established to ensure that surface water quality is not impaired by the discharge of contaminated groundwater into a surface water body at contaminant concentrations above the Water Quality Standards.
Volatilization Criteria are established to protect human health from volatile substances in groundwater that may migrate from the groundwater into overlying buildings.  The Volatilization Criteria for groundwater vary depending on whether the overlying building is used for residential or industrial/commercial purposes.  In cases where the industrial/commercial Volatilization Criteria are appropriate, an Environmental Use Restriction must be recorded to ensure that the site is not used for residential purposes in the future.
Environmental Use Restriction
Under specific circumstances, an Environmental Use Restriction (EUR) (Section 22a-133q-1 through 22a-133q-9 of the RCSA) may be considered as an alternative to remediating contamination to a concentration that is consistent with specific criteria of the RSRs.  The purpose of an EUR is to prevent certain types of uses of a property, or to limit or require specific activities on a contaminated property, or to minimize the risk of exposure to the pollutants.  For example, an EUR may prohibit the destruction of a building located above contaminated soil to prevent the contamination from being exposed.  An EUR must be recorded on the municipal land records.  The option of using an EUR is at the discretion of the property owner.
Contact Information
HARTFORD, CT 06106-5127

This overview is designed to answer general questions and provide basic information. You should refer to the appropriate statutes and regulations for the specific language. It is your responsibility to comply with all applicable laws. The information contained in this fact sheet is intended only to acquaint you with the Remediation Standard Regulations. In the event of inconsistencies between this document and the Remediation Standard Regulations, the language in the Remediation Standard Regulations controls.

Connecticut Remediation Standard Regulations

Content Last Updated February 16, 2021