Mound Systems for On-site Wastewater Treatment

Siting, Design and Construction in Ohio

Bulletin 813

Mound System Design Example

Step 1. Evaluate Site Location for Mound System.

A mound system is proposed for treatment and disposal of domestic wastewater for a three-bedroom residence. On a site that meets the recommended soil and site criteria, establish the contour of the lot and mound area. Stake out the mound so that the absorption bed runs parallel to the contour. Mounds must be on the contour to maintain constant mound height and to ensure even distribution of effluent. Mound systems should be installed 50 feet or more from existing wells and more than 10 feet from the property line. Paint lines between stakes in case stakes are disturbed.

A summary of the soil and site information is given below. Confirm the described soil and site description prior to designing a mound system for the site.

1. Soil Profile (summary of three soil excavations based on shallowest values):
   1. 0-10 inches: silt loam texture; strong, moderate, angular blocky structure; friable consistence
   2. 10-26 inches: sandy clay loam texture; moderate structure; friable consistence
   3. 26-36 inches: clay loam texture; moderate, fine platy structure; firm consistence
   4. Below 36 inches: shale bedrock
2. Site slope is 12%.
3. The area available is 160 feet along the contour and 50 feet along the slope. Three medium-sized trees are in the mound area.
4. Depth to limiting condition is 26 inches due to fine platy structure creating a restrictive layer.