This is an Administrative Order (AO) issued on April 18, 2007 by U.S. EPA, Region 9, Water Division, Drinking Water Office, against the U.S. Dept. of the Navy, San Clemente Island (offshore from San Diego, California). The Navy facility on San Clemente Island exceeded the total trihalomethanes (TTHMs) standard under the Stage 1 Disinfectant and Disinfection Byproducts Rule. Monitoring results indicate that the running annual average for total TTHMs is 99ppb. The current standard is 80 ppb for total TTHMs. The water system serves about 700 persons and is located offshore, about 67 nm west of San Diego, California. The order requires Respondents to submit a compliance plan by June 30, 2007 and to be in full compliance with the total TTHMs standard by December 31, 2008.