What does it cost? Every septic system is different so we provide a firm price only after we have seen plans and visited the site. The following prices are an approximate guide to systems on easily accessible blocks in the Adelaide Hills at the beginning of 2006. If budgeting, we suggest close scrutiny of your builders quotation as sometimes drainage from slab to septic tank is not included. Standard system for up to 6 persons: Standard System for up to 6 persons with spa or tub for two: Standard system for up to 8 persons $8,250 (plus GST) $9,250 (plus GST) $9,700 (Plus GST) If your block has adequate slope and room for complying irrigation below the filter you may be able to install a gravity only system saving money. We urge you to contact us for a site visit and a firm obligation free price. All blocks are different! The prices given above include for excavation, supply and construction of a system complete with septic tank and filter. Also included is the supply of pipe and fittings for garden irrigation, pump and alarm etc. The new owner receives a kit that includes a comprehensive manual. The prices do not include for any drainage upstream of the tank, the laying out of the irrigation or electrical power work. ..Home.