Correcting Septic System Drainage Issues Related to Erosion and Depression


Often times with older septic systems, the soils surrounding the lateral lines, cesspit, septic tank, leach field or drain field become eroded or depressed. This settling action is often times normal but it can affect the amount of water entering our drainage areas. 

Since most systems contain perforated piping or walls (as in a cesspit), along with gravel surrounding the piping, the systems themselves act somewhat as sponges that collect rain water from the surface or subsurface. When you have areas that are lower than the rest of your yard, these areas will collect water more easily. In some cases, puddling is evident on top of or around your drainage areas while in other cases, the collection takes place below ground. This erosion can take place regardless of whether or not your system is installed in flat areas or on hilly slopes. 

If you have erosion, system performance can be increased by up to 20% once the condition is rectified. In order to fix the dip areas (and if you are legally allowed to do so), you will need to have soil delivered to raise and low areas to a level at least 1 inch higher than surrounding soils. For instance, let’s say that you have an 80 foot leach line with the entire length of the line roughly 1 inch below grade. You will want to have enough soil delivered to rake over the line area so as to have the entire line area 1 inch higher than surrounding sols. Pitch the raised area so that water flows down the sides and away from the lines. The same method would apply to cesspits, leach fields, drain fields, tank areas and lateral lines. 

All of these areas need to somewhat repel water in order to function at peak performance. Since septic system and drain field replacements can be quite costly, assuring drainage factors are optimal will yield maximum results.

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