If you are planning to install a new septic system, replace an old septic system or alter your existing septic system you are required to obtain a permit from the health department before the work can be completed. The type of septic system you need is based on the site-specific soil characteristics of your lot. The Ohio sewage rules stipulate minimum standards which will guide the types or designs of systems that are allowed on a lot. Not all lots can be developed and served by an on-lot sewage treatment system. Limiting factors such as flood plain/flood way, saturated soils, excessive slope, waterways/swales can sometimes make system design very difficult or even impossible.