Septic system design
Septic systems require care in site selection, design and construction. Every individual conventional septic tank absorption field system must be designed and constructed according to State Board of Health regulation, 410 IAC 6-8, as explained in Residential Sewage Disposal Systems (available through your County Board of Health). A FACTS computer program is available at your local County Extension office that can make recommendations for several types of on-site septic systems for use with various site and soil conditions. If a conventional system is suitable for your situation, the program will provide the following design information: estimates of the septic gravel volume, total trench bottom area required, and depth to the trench bottom. It will also plot specific layouts of the septic field for various trench widths that will best fit the shape and size of the disposal area.