In 2004 URS carried out a study for the Bexar Medina Atascosa Water District (BMA) in order to identify properties which were likely to have on-site sewage facilities (OSSFs). These properties, if built after 1997 would be required to comply with regulation governing the construction and maintenance of OSSFs in Texas. The study was commissioned following a rise in fecal coliform levels in Medina Lake and concern from BMA that OSSFs were a potential source of contamination of the lake.