Best Practices for Mound Systems
- • Use mound systems only when there is a high water table, shallow soil cover over cracked or porous bedrock, or soil permeability is either extremely high or extremely low.
- • Determine how best to design the mound system by how the effluent moves away, the direction of flow, and how fast it travels away from the system.
- • There should be at a minimum 1 foot of highly permeable soil between the mound system and the inhibiting ground conditions unless local or state ordinances direct otherwise. However, it is recommended that there be at least 4 feet of highly permeable soil between the mound and the inhibiting ground conditions.
- • Mounds appear to work best when they are long and narrow and if the conditions of the soil are very poor, the system should be longer and narrower.
- • Mounds can be placed on slopes of up to 25%, however steeper slopes are not advised because of the danger to the equipment operator in working in this type of environment.
- • Where a site has been filled with soil, in the case of the mound system, the soil should be placed on top of the natural soil and allowed a time to settle before utilizing a mound system.
- • Mounds must not be installed in flood plains. They must not be installed in drainage ditches or depressions unless there are specific flood protections for the most severe type of floods. They should be separated from water supplies, surface waters, springs, the boundary of the property, and the house according to the local or state ordinances.
- • Install a mound system that will have sufficient reserve for expansion, and have an upper limit of the number of people allowed to use it, in order to prevent hydraulic overload and biological clogging of the system.
- • On a periodic basis, check the septic tank and dosing chamber to make sure that the sludge and scum buildup is not too great to avoid overloading the mound system. Have the septic tank and dosing chamber cleaned out as needed by professional sewage haulers. (See endnote 18.)