What is the Purpose of a Drain Field?
A drainfield serves the purpose of a secondary treatment of the sewer water prior to percolating into the soils. (Aerobic Treatment)
Since water does not all percolate at once it is designed to hold a pre-determined amount of water waiting to percolate. (Such as several loads of clothes in one day, visiting guests)
A drainfield is designed to last for many years if not the life of the home, if properly maintained and not abused. One way to assure long life of your drainfield is to have your septic tank pumped at least every 3 years. A septic tank size is designed to hold a certain volume of water for that particular house. If a septic tank is overloaded with sludge and scum it does not have the available capacity to operate efficiently.
What can cause a Drain Field Failure?
1. Killing the bugs – The bacteria in a standard septic tank is called anaerobic. That is, it does not require oxygen. In fact, too much oxygen will kill the bacteria. Without the bacteria a septic tank does not work. Water contains oxygen.
Where does excessive water come from?
a. Water shedding off the roof onto the septic system.
Solution – Install rain gutters and direct the water away from the septic system.
b. Leaking toilets
Solution – Adjust the floats and/or replace the valves in the water closet.
c. Too much laundry. Excessive water use over a short period.
Solution – Space the laundry over 2 or more days.
2. Plugging the Drain Field pipes – Planting root prone trees such as fichus or large oak and pine trees near the drainfield. Those roots seek out the water and plug the pipes.
3. Building over the Drainfield – A drainfield evaporates approximately 30% of its water through the air above. Never compact the soils by paving, building, or driving over a drainfield.
How we repair Drain Fields
First we analyze the soils, determine the ground water table, draw a plot plan, and apply for and obtain the Health Department permit.
There are two ways to repair a failing drainfield:
1. Complete removal of all the failed drainfield.
This involves removing the rock and/or pipe, hauling it to a holding station.
Replace any unsuitable soils and lay in a new drainfield, call for a State Health Department Inspection, and cover up.
During this process we must watch for underground utilities such as irrigation systems, telephone, water, and gas lines. Sometimes trees or other obstacles must be removed.
Sod, of course, can be replaced by Coastal Septic, or by the homeowner.
In some cases (but not all) the failing drain field is restored using our Revitalizer machine.
This is an air injection machine that breaks up the plugged rock and soils. This can e a very effective means of restoring the drain field. However, the original cause of failure must be determined to avoid the recurring failure. This is true for both Revitalizing and complete drain field replacement.
Revitalizer is not recommended or warranted for older terra cotta drain fields.
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