Ground Water Rule

The Ground Water Rule (GWR) was promulgated by U.S. EPA on November 8, 2006 to provide increased protection against pathogens in public water systems using ground water sources. Starting on December 1, 2009, the rule requires public water systems to conduct triggered source water monitoring, unless they demonstrate 4-log (99.99%) removal or inactivation of viruses.  For more information, see the letter sent to community and major noncommunity public water systems for more information on upcoming requirements.

Application Form for Ground Water Rule 4-log Treatment of Viruses (due September 1, 2009):

• For systems that disinfect with chlorine and are claiming 4-log credit based on clearwell and/or pipe storage
• For systems that disinfect with chlorine and are claiming 4-log credit based on pipe storage only

Excel spreadsheet to determine contact time:

• for cylindrical tanks and pipe only
• for rectangular clearwells
  • baffled
  • unbaffled

Ohio EPA Q & A on Ground Water Rule

Noncommunity public water systems serving less than 1000 people are encouraged to review U.S. EPA's fact sheet on the Ground Water Rule. Additional information is also available on the U.S. EPA Web site.