How to Install a Dry Well Septic System

All soils do not absorb water at the same rate. For this reason, septic systems are required to have varying amounts of field line. The slower the rate of absorption, the more field line required. A dry well septic system is an excellent alternative for an area with an unusual rate of absorption. While these system use the same principle as a standard septic system, the design is quite different.

Things You'll Need

• Septic tank
• Seepage tank
• PVC pipe
• PVC pipe cleaner
• PVC pipe cement
• Backhoe
• Tape measure
• Level
• Rake
• Gravel

Instructions

1. Dig a hole for the septic tank with the backhoe. This hole should be a minimum of 10 feet from the foundation of the house. The hole will need to be approximately two feet wider than the tank and 12 to 18 inches deeper. Dig a trench from the house to the hole for the septic tank. From the other side of the septic tank, dig a trench to the location for the seepage tank. If this is to be a gravity-feed system, the seepage tank must be lower than the septic tank. The size of the seepage tank will be determined by the results of a perc test, which determines the absorption rate of the soil.

2. Install the septic tank, making certain it is as level as possible. Modify the bottom of the hole however needed to make certain the tank will be level when installed. You should allow a professional with the proper equipment to place both tanks into the holes. A concrete septic tank can weigh several thousand pounds and be very hazardous for an amateur to handle. Once the septic tank is in place, connect the inlet side of the tank to the house drain with four-inch PVC pipe. Clean all pipe joints and fittings with PVC pipe cleaner before applying the pipe cement. This will help ensure a leak-free system.

3. Pour a layer of gravel into the seepage tank pit and rake it so it's smooth and level. Have the seepage tank lowered into the hole, keeping it level and centered. This tank will have several openings covered with a filtering material to allow water to slowly seep out of the tank to be absorbed into the surrounding soil. Around the outside of the seepage tank, pour a thick layer of gravel. This layer should cover the tank from its base to the top edge. This allows for better absorption and helps keep the seepage holes from getting clogged with dirt. The seepage tank will be connected to the septic tank by four-inch PVC pipe. Once again, be certain to clean all fittings and joints before applying the cement.

4. Once all inspections have been completed, the holes and trenches can be back-filled and raked until they're smooth. Be certain to slightly mound the dirt to allow for settling. The location of both tanks should be marked in some manner. A partially buried stepping stone over each tank will help you find them years later when maintenance is required. Another excellent method is to take pictures of the entire system before any back-filling is completed. The pictures can later be used to help find the various components if necessarry.

Tips & Warnings

• Fill the septic tank with water to help prevent it from floating out of the hole should a heavy rain saturate the area.

References

• Maryland Cooperative Extension: Septic systems