Groundwater Professional Bulletin Board

Water Supply Notifications

Currently the Water Supply Notification (DNR Form 542-1530) is sent to the Department of Natural Resources (DNR) Water Supply Section and, if applicable, the delegated county authority responsible for issuing private water supply construction permits when:

• A protected groundwater source exists and the maximum concentration exceeds the Tier 1 levels (e.g., 290 PPB for benzene) for potential receptors.

OR

• If the receptor type is potential due only to an existing protected groundwater source, and the maximum concentrations are below the Tier1 levels for potential receptors, but exceed the Tier 1 levels (e.g., 5 PPB for benzene) for actual receptors.

We have had instances where LUST sites, located in areas that were not a protected groundwater source, were reclassified from low to high risk due to the installation of drinking water wells. In an attempt to prevent this occurrence, we are modifying our guidance to require the Water Supply Notification to be sent whenever the maximum concentration of petroleum compounds exceeds the Tier 1 levels for actual receptors. The groundwater source classification is irrelevant. This guidance change is effective with Tier 1 or Tier 2 Reports submitted to DNR after June 1, 2004.

Contact Elaine Douskey at (515)281-8011 or elaine.douskey@dnr.state.ia.us if you have questions.