Private Property I/I Control Program in Greencastle, Indiana

The City of Greencastle initiated an infiltration/inflow (I/I) reduction program to reduce I/I from private property sources in 2003. Greencastle's I/I policy requires certified inspectors to document that privately-owned properties do not contribute excessive rain water to the sanitary sewer systems. Residential properties are inspected upon requests for a new water service, which typically occurs upon change of ownership. Non-residential properties were required to be inspected within two years of program initiation and have been completed. If an inspection finds a defect, property owners must either fix the defect immediately or apply for a waiver. A waiver can only be granted when fixing the defect is impractical or too costly. Compliance inspections typically cost 30 to 50 and are scheduled and paid for by the homeowner.The policy is making a difference. After just a few years in effect, WWTP operators noted lower average daily flows and lower peak flow rates. Prior to implementing the policy and companion public side I/I removal efforts, rain events would often cause peak flows of 16 million gallons per day (MGD). Currently, heavy rains are needed for peak flows to exceed 5 MGD. Before the policy, the treatment plant would need to treat increased flows for several days and sometimes weeks after a rain event. Now, operators observe that treatment plant flows return to normal within 24 hours. Manholes that frequently surcharged to the surface prior to implementing the policy now do not surcharge. The City views the policy as an unqualified success at reducing I/I in the collection system.The United States Environmental Protection Agency (USEPA) and the Water Environment Research Foundation (WERF) jointly funded a program to document the effectiveness of the I/I reduction program. In the spring of 2007, Greencastle installed flow metering at four of locations that had been metered prior to initiating the I/I reduction program which allowed a comparison of pre- and post-rehabilitation flow rates. This paper reviews the design of the program, provide an update on the implementation of the program, and presents data documenting costs and benefits.