A mound septic system is one of several different types of septic systems. Each septic system is designed to overcome certain environmental, soil or water problems where a conventional septic system is not preferred or does not meet local standards. A Mound system is based on the Nodak disposal system developed in North Dakota. At the time this was a revolutionary way to distribute effluent flows safely in specific situations.
A mound septic system also called a sand mound septic system and is one of the preferred alternative septic systems by a septic system expert in places with shallow soil depth, poor soil structure, high groundwater or water table, or shallow bedrock that is close to the surface. In these situations, most septic systems would not be suitable.
The drain field or leach field is contained within a constructed sand and gravel mound over suitable soil and potentially porous bedrock. Wastewater and effluent exiting the tank flows to a distribution box containing a pump chamber. From there it is pumped to the mound in specific, prescribed amounts. Within the septic mounds are a network of distribution pipes sitting in sand fill. Controlled amounts of effluent are pumped through the small pipes at low pressure. This allows the effluent to trickle down through the entire mound, including layers of sand and gravel, eventually into the soil beneath the mound where the removal of pathogens and harmful viruses is completed. A major difference from a conventional system is the drain field is not gravity fed, it relies on a pump. If the pump fails, the septic tank can back up fast.
With any septic system, there are pros and cons or advantages and disadvantages. That is why alternative systems have been created for when a gravity-fed traditional system does not work on your site. Below are some of the pros and cons of this specific system.
Protects groundwater - a high water table is protected with the use of mound septic over traditional septic systems
Lower installation costs - compared to conventional septic systems, the installation cost is lower as the installation happens above ground for the leach field.
Soil absorption - your septic system design is not limited by your soil type such as lighter soils or heavy soils. The mound septic system will prevent wastewater effluent from reaching groundwater or running off in heavier soils.
Space needed - Although mound systems can be a good solution in many situations, they require a large amount of space and it is a requirement in most states to have a dedicated mound site and replacement area in case the onsite wastewater treatment site fails. The septic system also needs a flat or low gradient yard so that surface pooling and runoff do not happen during high usage.
Unsightly - As the name infers leaves a large mound on top of the natural soil surface, above the ground in your yard. If you have a large backyard then this will not be a problem, but it can be an eye saw for many homeowners compared to a traditional septic system.
Repairs & maintenance - Costly repairs come with this wastewater treatment method. The mound system is more complex than a below ground, traditional septic system.
Not gravity fed - Because a mound septic system relies on a pump and pressure distribution between the septic tank and the leach field, if the pump malfunctions there is no gravity to move effluent from the setpic tank and this can mean the septic tank backs up quickly. This will often result in the septic tank alarm going off and costly repairs and the need to have your septic tank pumped.
A common question is how much does a mound septic system cost. Pricing can range depending on many different factors. Access to your property will determine what size of heavy equipment can fit down the side of your building if you are replacing your septic. In most cases sand, gravel and soil will need to be trucked in. If your property is rural then this may be many miles from a quarry or supplier. To get a free quote on new septic or to replace an existing call the nationwide install and replacement professionals click here to get a free quote.
The pictures of a mound septic system is sourced from the EPA and is not to scale. If you're looking to maintain your septic system read more about septic system treatments.
