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Mound or Drainfield: What's The Difference?

Septic systems are essential for managing household wastewater in areas without access to municipal sewer systems. When it comes to choosing the right septic system for your property, there are several options available, each with its own set of advantages and considerations. Two common types of septic systems are mound systems and drainfield systems. Let's explore the differences between these two systems to help you make an informed decision on which system fits your needs best.

Mound Septic Systems:

1. Overview: Mound septic systems are typically installed in areas with high groundwater tables, shallow bedrock, or poor soil drainage. In a mound system, wastewater from the household flows into a septic tank, where solids settle and liquids are treated. However, instead of discharging the treated effluent into a drainfield buried underground, it is pumped to a raised mound of soil specially constructed on the property.

2. Construction: The construction of a mound system involves building a raised bed or mound of sand or gravel above the natural soil surface. This mound is then covered with soil and vegetation to blend in with the surrounding landscape. The raised elevation of the mound provides additional distance for the effluent to travel through the soil, allowing for further treatment before it reaches the groundwater.

3. Advantages:
-Suitable for areas with poor soil drainage or high groundwater tables.
-Provides enhanced treatment of wastewater due to the increased distance and contact time with soil.
-Can be installed on properties where traditional drainfields are not feasible.

4. Considerations:
-Higher installation costs compared to traditional drainfield systems due to the additional materials and labor required for mound construction.
-Requires periodic maintenance, including monitoring of soil saturation levels and potential mound settling.

Drainfield Septic Systems:

1. Overview: Drainfield septic systems, also known as leach fields or absorption fields, are are another common type of septic system. In a drainfield system, treated effluent from the septic tank is distributed through perforated pipes buried underground in a designated drainfield area.

2. Construction: The construction of a drainfield system involves excavating trenches in the soil and laying perforated pipes in a bed of gravel or aggregate. The pipes allow the treated effluent to disperse evenly into the surrounding soil, where it undergoes further treatment through natural processes such as filtration and microbial action.

3. Advantages:
-Lower installation costs compared to mound systems, making them a more economical option for many properties.
-Suitable for a wide range of soil types and site conditions.
-Minimal maintenance is required beyond periodic tank pumping and inspection.

4. Considerations:
-Not suitable for properties with high groundwater tables, shallow bedrock, or poor soil drainage.
-May require replacement or repair if the drainfield becomes clogged or fails due to soil compaction or root intrusion.

Choosing between a mound septic system and a drainfield system depends on various factors, including site conditions, soil type, and budget constraints. Mound systems are ideal for properties with challenging soil and groundwater conditions, offering enhanced treatment capabilities at a higher initial cost. In contrast, drainfield systems are a more cost-effective option for properties with suitable soil and site conditions, providing reliable wastewater treatment with minimal maintenance requirements. By understanding the differences between these two types of septic systems, homeowners can make informed decisions to meet their wastewater management needs effectively.


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