Projects – Past & Present. Extensions and Connections (E & C) BTR currently constructs for SA Water, their water and sewer Extension and Connection (E&C) of existing and new services. Water Main Relay (WMR) BTR constructs the Water Main Relay (WMR) projects for SA Water to replace the city’s aging water mains in the metropolitan area. Maintenance work for Allwater BTR have been engaged by Allwater (who maintain the SAW assets in metropolitan Adelaide) to perform maintenance on their behalf. Works for local Councils BTR performs civil works for local Councils involving Stormwater, Water, Sewer, Recycled Water and Manhole replacements.