May 2009 – North Carolina Groundwater Standards to Become More Stringent for 15 analytes

North Carolina is currently reviewing its groundwater water quality standards and interim maximum allowable concentrations and has indicated that allowable concentrations associated with 15 groundwater standards will decrease. This could have a significant impact on any investigation or remediation projects your company is currently undertaking.

Every three years the State is required, by 15A NCAC 02L .0202, to review its groundwater water quality standards and interim maximum allowable concentrations to determine if changes are needed and, if necessary, to make those changes. Revision of these standards is needed to ensure that they contain the most recent health and toxicological information.

Summary of Proposed Rules

Based on review of the most current and relevant toxicological information available, the proposed changes to groundwater standards include:

  • a decrease in the allowable concentration for fifteen standards
  • an increase in the allowable concentration for twelve standards
  • the addition of a standard for formaldehyde
  • the removal of twelve standards and/or interim maximum allowable concentrations (note that these contaminants are still regulated under this rule and that concentrations exceeding the practical quantification limit (PQL) would constitute a violation of the standard)
  • the reduction of significant figures to one
  • a change in the units of measure from mg/L (parts per million) to µg/L (parts per billion), except where noted
  • an update of ten chemical names
  • the substitution of the language “at or above the practical quantitation limit” for the term “detectable.”

Copies of the proposed rules can be found at the NC Department of Environment and Natural Resources, Division of Water Quality web page at

Possible Effects

An increase or decrease of a current North Carolina groundwater quality standard affects which constituents of concern for a given site are violating these standards. If the maximum allowable concentration is lowered, chemical concentrations that were previously acceptable now may require additional action.


The earliest these changes would become effective would be November of 2009, but it is estimated that any changes will go into effect between January and June 2010.

How EHS Support can help?

  • We can assist you in understanding the impact of the proposed changes on your facility, investigation, or remediation project
  • Determine the potential financial and technical impact the changes in these standards may cause
  • Support your staff in submitting public comments
  • Facilitate communication and advocate your interests to the NC DENR

If you require further assistance or would like to discuss how these changes will impact your company, please contact Rick Henterly at 412-855-3727 or



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