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On April 23, 1993, the Edwards Underground Water District (EUWD) received a completed application form from Fort Sam Houston requesting a leak detection/location survey on its water distribution system.

Pre-survey conferences were held June 14, 1993 and June 21, 1993 at the Environmental and Natural Resources Division to discuss the work to be performed. It was agreed that EUWD would perform sonic leak detection on all available access points, computerized leak location as needed, record any unusual system conditions found, and submit to the Post a revised master water plat with the final report. It was further agreed that Fort Sam Houston would provide EUWD with one experienced utility service person and would repair all leaks detected in a timely manner.

Mark L. McGinnis of EUWD began the survey on July 22, 1993, and the survey was concluded on February 4, 1994. Over the course of the survey, Mr. McGinnis surveyed a total of 2,751 access points including 1,133 customer service connections, 447 fire hydrants, 1,064 main valves, and 107 other access points covering 68.3 miles of distribution and transmission mains. Computer leak sound correlation was performed on one location.

Mr. McGinnis detected a total of 177 leaks. This total included 42 service valve leaks, 42 main valve leaks, 42 fire hydrant leaks, 29 customer side leaks, and 22 main leaks. Additional leaks are suspected at many of these locations, but cannot be located until repairs are completed on all known leaks . As of February 4 , 1994, 39 of the 177 leaks detected over the length of the survey have been repaired. EUWD estimates 170,580 gallons of water per day has been saved by the repairs to date. The leaks detected during this survey range from 144,000 gallons per day to numerous small service valve leaks.

As part of the survey, Mr. McGinnis located 249 service valves, 97 main valves of various types, 31 fire hydrants, and .89 miles of distribution main not shown on the master plats . EUWD staff was unable to locate 109 main line valves, 91 service valves, 24 fire hydrants and 24 assorted valves. An additional 194 valve stacks need cleaning and/or repair.