NGWA and EPA meet to discuss stormwater infiltration impacts to groundwater

August 17, 2020

Recognizing potential significant impacts to managed aquifer recharge, NGWA CEO Terry S. Morse, CAE, CIC, and NGWA Regulatory Affairs Manager Chuck Job recently met with U.S. Environmental Protection Agency managers to address concerns raised in two recent reports of EPA and the National Academy of Sciences that stormwater infiltration to the subsurface needs further research.*

Morse and Job participated in a video conference with Suzanne VanDrunick, EPA national program director for the Safe and Sustainable Water Resources Research Program; Bruce Rodan, EPA associate director for science for Office of Research and Development (ORD); and other EPA staff on August 10.

Discussed were the two recent reports noting design guidance — including pretreatment — is needed before utilizing infiltration as a stormwater disposal practice. NGWA presented results from case studies done in nine states and 10 countries.

The EPA/ORD 2018 State-of-the-Science report on stormwater infiltration impacts to groundwater quality and the National Academy of Sciences 2019 report on industrial stormwater permits both indicate inadequate understanding of impacts to groundwater quality from stormwater infiltration. In fact, EPA’s research on stormwater infiltration impacts to groundwater quality was reduced to just three sites, which are not representative of the 48 hydrogeologic settings previously documented by EPA.**

It was also noted in the meeting that research is needed to examine the quality of stormwater infiltration practice treatment and vadose zone effects to demonstrate compliance with Safe Drinking Water Act underground injection control and groundwater protection requirements for a range of hydrogeologic settings.

So how will groundwater sources be protected? NGWA’s proposal was this: The EPA should continue the funding of adequate research on stormwater infiltration impacts to provide groundwater-protective design guidance that gives communities served by groundwater confidence in stormwater management.

The EPA managers indicated ORD was pursuing enhanced aquifer recharge (EAR) research that may be applicable to stormwater infiltration practices. NGWA responded that EAR research can indeed have important support for addressing stormwater infiltration practices in large communities but may not be applicable to small- and medium-size communities only needing to dispose of stormwater.

NGWA is going to follow up with EPA manager Chris Impellitteri, the associate national program director for EPA’s Safe and Sustainable Water Resources Program, who asked for continued NGWA input regarding EPA research. NGWA is also going to pursue support from other interested associations.


* National Academies of Sciences. 2019. Improving the EPA Multi-Sector General Permit for Industrial Stormwater Discharges.; US Environmental Protection Agency. 2018. The Influence of Green Infrastructure Practices on Groundwater Quality: The State of the Science.

** USEPA. 1985. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrogeologic Settings. EPA/600/2-85/018. Washington, D.C.