Mound Septic Systems in Mobile, AL: What Homeowners Need to Know
A mound system is an elevated drainfield built above the natural soil level. It's used in areas with poor soil, a high water table, or shallow bedrock. In Mobile, AL, mound systems are common near waterways and in areas with clay soil. They require careful maintenance and regular inspections to ensure they function properly. Understanding your mound system is key to its longevity.
If you've ever driven through Mobile and noticed a long, grassy mound in a yard, you might have wondered what it was. Often, it's a mound septic system. This type of system is an alternative to a conventional drainfield, designed for properties where the soil is too shallow, too permeable, or too slow-draining for a standard system. In Mobile, Alabama, with its varied soil types and high water table, mound systems are a common and effective solution. However, they are more complex than conventional systems and require specific maintenance. This guide provides everything you need to know about owning and caring for a mound system.
What Exactly Is a Mound Septic System and How Does It Work?
A mound system is a type of drainfield that is built above the natural ground surface. It consists of a septic tank (for primary treatment), a pump tank, and the mound itself. The mound is a raised bed of sand, gravel, and topsoil. Wastewater from the tank is pumped up into the mound, where it flows through a network of perforated pipes. The water trickles down through the sand and gravel, where it is treated by bacteria and other microorganisms. The treated water then filters into the natural soil below. The mound provides the necessary "soil depth" to treat the wastewater. In Mobile, mound systems are often required on lots with less than 2 feet of suitable soil, or where the water table is within 2 feet of the surface.
Why Is a Mound System Used in Mobile, AL?
There are several reasons why a mound system might be the best or only option for your property in Mobile:
- Shallow Soil: :If your property has bedrock or a hardpan layer close to the surface, there isn't enough depth for a conventional drainfield.
- High Water Table: :In areas near Mobile Bay or rivers, the groundwater is often too close to the surface. A mound system raises the treatment zone above the water table.
- Poor Soil Permeability: :If you have heavy clay soil that drains too slowly, a mound can help by creating a more porous environment for treatment.
- Small Lot Size: :A mound system can be designed to fit a smaller footprint than a conventional drainfield.
- Environmental Regulations: :In environmentally sensitive areas, mound systems may be required to provide a higher level of treatment to protect water quality. A mound system is a viable solution for many challenging sites.
What Are the Common Problems with Mound Systems?
Mound systems are generally reliable, but they are not without their issues:
- Pump Failure: :The system relies on a pump to deliver wastewater to the mound. If the pump fails, the system stops working.
- Clogging: :The sand and gravel in the mound can become clogged with solids if the septic tank is not maintained.
- Hydraulic Overloading: :Sending too much water into the system can overwhelm the mound, causing it to fail.
- Erosion: :The mound can be susceptible to erosion from wind and water if not properly vegetated.
- Root Intrusion: :Tree roots can infiltrate the mound if trees are planted too close.
- Freezing: :In Mobile's mild climate, freezing is rare, but a prolonged cold snap could affect the mound. In Mobile, the biggest risk is pump failure during power outages or storms.
How Should a Mound System Be Maintained in Mobile?
Proper maintenance is essential for a mound system. Here's what you need to do:
- Pump the Tank: :The primary septic tank needs to be pumped every 3-5 years.
- Inspect the Pump: :Have the pump and its controls inspected annually.
- Check the Alarm: :Ensure the alarm system is working. It will alert you to a high water level or pump failure.
- Protect the Mound: :Don't drive or build on the mound. Keep heavy equipment away.
- Manage Landscaping: :Plant only grass on the mound. Keep trees and deep-rooted plants away.
- Direct Water Away: :Ensure gutters and downspouts discharge away from the mound.
- Monitor the System: :Keep an eye out for any signs of trouble, such as odors or wet spots. A mound system is a significant investment, and proper maintenance will protect that investment.
Frequently Asked Questions
How much does a mound system cost compared to a conventional system?
Mound systems are generally more expensive than conventional systems because they require more materials, a pump, and a more complex design. The cost is a significant factor to consider.
How long does a mound system last?
A well-maintained mound system can last 20-30 years or more. The lifespan depends on the quality of the installation, the maintenance, and the usage.
Can I plant a garden on top of the mound?
No. The mound is part of the treatment system. You should not plant anything other than grass on it. Deep cultivation or root systems can damage the mound.
What happens if the pump fails?
If the pump fails, the wastewater will not be pumped into the mound. The tank will fill up, and the alarm will sound. You need to call a professional immediately to repair or replace the pump.
Does a mound system require a permit in Mobile?
Yes. Any new installation or significant repair of a mound system requires a permit from the Mobile County Health Department. The installation must be done by a licensed professional.