When considering a potential site, keep in mind the prevention of runoff. Site evaluations should begin with a topographic map of the proposed site. An aerial photograph is also useful. Shade in areas where wastewater application may have some restrictions. Maps and reports documenting restrictive features are available through the Natural Resources Conservation Service (NRCS) and the Ohio Department of Natural Resources (ODNR). Restrictive features of a site include areas with:
| Source of information | |
| 10-year flood frequency | Flood insurance maps |
| All streams, waterways, wetlands, springs, ponds, and lakes | NRCS county soil survey |
| Greater than 15 percent slope | NRCS county soil survey |
| Less than 1 foot to seasonal water table | NRCS county soil survey |
| Less than 2 feet to bedrock | NRCS county soil survey |
| 100 feet from dwellings, roads, and other structures | aerial photo or site visit |
| 100 feet from an operating or abandoned well | Site visit or ODNR well logs |
| Subsurface drainage systems and storm sewer | Site visit or drainage district |
Next outline the area being considered for wastewater application. Indicate throughout:
Finally, test the soil on the proposed site to insure it was not contaminated by previous activities. Collect a composite soil sample from every 10 acres of application area to determine background levels in mg/kg of:
For systems over 150,000 gpd, information on the groundwater in the area is important. The depth to groundwater aquifers in the area can be obtained from the county groundwater map published by ODNR. The direction of groundwater flow beneath the site can be determined by a hydrogeologist.