SOIL COMPACTION in the area reserved or already used for the soil treatment area on building sites with septic systems or other onsite wastewater treatment systems must be prevented.  Soil compaction results from heavy loads due to traffic and stockpiling of materials or excavated soil.  Compaction breaks soil peds and compresses soil particles closer together.  This reduces pore space, thereby, reducing water and air movement through soil.  Water and air movement is essential for treatment of wastewater.


Keep equipment, vehicles, construction materials and large animals off the soil treatment area both before and after construction.  Soil compaction can produce premature failure of the soil treatment system.


Compaction may go to a depth of 20 inches, depending on the load and soil conditions.  The depth is usually greater if the soil is wet and ruts form.  The effect of compaction may be reversed by tillage, freezing and thawing, and wetting and drying over years.  However, this is usually limited to the upper 10 inches.  Once a soil treatment area is in use, wetting and drying and freezing and thawing cycles do not occur below 10 inches.  The effect of compaction will persist for decades.  This persistence of reduced air and water movement demands that all individuals involved in the design, construction, and landscaping of a home, including the onsite wastewater treatment system, refrain from driving, parking, storing materials and pasturing large animals on the soil treatment area. This area should be marked or fenced during construction.  Signs for this purpose are available from the Michigan Onsite Wastewater Training Center (MOWTEC) at Michigan State University.






Signs are on heavy vinyl material suitable for fastening to stakes or posts using nails, staples or ties.  They are available in 6 X 9 format and can be mailed in any quantity.  They are red in color and sufficiently durable to be reused several times. 


Cost varies by quantity ordered and includes postage, handling and sales tax.


Cost per sign:             1-9                  $2.00                          

                                    10-49               $1.75

                                    50-100             $1.50

                                    >100                $1.25


Make checks payable to:   Michigan State University


Send request to:            MOWTEC Signs

                                    % Barb Delong

                                    Department of Biosystems and Agricultural Engineering

Farrall Hall

                                    Michigan State University

                                    East Lansing, MI 48824


Shipping Info:


Number of signs:  __________


Total remittance:  $_________


Mail to:


Name: ______________________________________


Address:  ____________________________________






            October, 2004