Septic tank maintenance is important and just because it’s underground and sort of forgotten about doesn’t mean you don’t need to take care of it.
When you neglect it, they are very difficult to ignore once they start acting up.
If you’re looking to install a septic system, purchase a home with an existing septic system or simply curious about your existing septic system this guide is for you.
Table of Contents
How Does a Septic System Work?
The little pipe that sticks out of the roof is the vent pipe.
It allows air to enter and leave the system as liquid floats through the pipes. It also vents harmful, poisonous and unpleasant gasses too.
All the various drains in the house are connected to one main exit pipe called the sewage lateral.
The sewer lateral is the underground pipe that goes from the house to the septic tank.
It usually goes through the home’s foundation wall but also can go through the home’s basement or crawlspace floor.
Everything that goes down every drain in the house ends up in your septic tank.
Your septic tank may be made of wood, concrete plastic, fiberglass or polyethylene. Some older ones may be made of cinder block or steel.
Regardless of what it’s made of the septic tank is where the waste water is separated into solid and liquid and where the first stage of the biological treatment occurs.
The tank will have several access hatches that will allow the inspection pump out in the tank.
Typical modern septic tanks hold 1,000 or 1,500 gallons. Tanks can be connected one after another in a series if required by the design.
The septic tank can have a single compartment or two compartments.
Some two compartment tanks may have a submersible pump in the second smaller compartment to pump liquid to the leach field if the outlet of the tank is lower than the leach field.
When all of the material is sucked out of the tank during servicing that material is defined as what is known as septage.
The liquid in the tank flows by gravity through a buried 4-inch diameter pipe called the effluent line to the distribution box.
Some septic systems use a pump help push the effluent through a small diameter pipe to the distribution box.
Sometimes a larger Wet Well that contains a submersible pump is located between the septic tank and the distribution box.
This is done when placing the pump into the septic tank is not practical.
The distribution box (D-Box) is a buried concrete or plastic watertight box with an access cover typically about 2 feet by 2 feet wide on each side and is used on all modern septic systems.
Its purpose is to equally distribute the liquid effluent to different pipes in the leach field.
What Happens Underground?
The inlet pipe forces the wastewater to turn toward the bottom of the tank preventing the wastewater from flowing directly across the top portion of the tank.
The solids that are heavier than water sink to the bottom and the lighter than water solids like oil, grease and plastics rise to the top.
In between is the liquid that will become the effluent that eventually flows into the leach field.
While this liquid is cleaner than the wastewater that flowed into the tank it still contains dissolved biological matter and water soluble chemicals.
The outlet pipe is designed so that only liquid leaves in a properly functioning tank.
The top of the pipe is in the air above the grease layer while the bottom of the pipe is in the liquid above the bottom solids layer.
For every gallon of wastewater, that flows into the septic tank, a gallon of effluent leaves the tank.
In the tank primitive anaerobic microbes live and feed on the biological matter.
These microbes don’t need oxygen to live and they reduce both the volume of the settled solids and the concentration of the dissolved biological matter in the liquid.
The Drainfield/Leach Field
The leach field is the most important part of a properly operating septic system. It’s the most expensive thing to replace and the easiest to damage.
The reasons for this are simple.
All the liquid portion of the wastewater that leaves the home must be dispersed by the leach field or the septic tank overflows or water can back up into the home.
Due to the intricate design and typical location of the field, it’s easy to compromise one of the critical design features by either improper operation or care.
Or sometimes by physically damaging the field by inadvertently crushing or cutting the pipe.
The leach field is typically a set of pipes with small holes in the bottom that lay in a trench that allows the effluent to flow into the soil after first flowing over gravel.
The pipes are covered with additional gravel and finally topsoil.
The flow of the liquid down through the gravel and into the surrounding soil pulls air down into the soil where oxygen using microbes are to further break down the dissolved biological matter.
Further down the soil depth where no oxygen is present other microbes finish the biological treatment process.
The soil itself also acts as a filter to remove many of the other chemicals and minerals in the affluent.
Septic System Do’s and Don’ts
- Do know where your system is located. If you don’t know contact the Subservice Systems Bureau. If the system was installed after 1975 they will be able to show you drawings showing where your system’s components are located. If the system is pre-1975 there still might be enough information in the archives to help you locate the components. This helps when you have service visits.
- Do have your septic system inspected and pumped by someone who is licensed.
- Do keep the vent pipes clear. Debris and even small animals can get in the pipe, clogging it and preventing the free flow of air into and out of the system leading to possible system backups.
- Do use septic-system friendly toilet paper, laundry detergent and bathroom cleaners. Try cleaning toilets, showers, sinks, and tubs with a mild mixture such as baking soda and vinegar.
- Do make sure there is easy access to the covers of the septic tank and D-Box for servicing.
- Do keep records of any repairs, inspections, pumpings, permits issued and any other septic maintenance activities.
- Do check with your local inspector/pumper before allowing a water softener’s backwash to enter your septic system.
- Don’t place anything on top of the leach field because it will interfere with the proper airflow into the ground.
- Don’t plant anything other than grass on top of the leach field because roots from bushes and trees will damage the structure of the field which could lead to failure.
- Don’t pour household hazardous waste, paints or used cooking oil down your drain. These can kill the vital microbes in the entire septic system and in severe cases clog the leach field leading to total system failure.
- Don’t drive over the leach field because this will compact the soil and reduce its ability to accept liquid and transfer air. In severe cases, the weight of the vehicle could crush the pipes.
- Don’t pasture large animals like horses over the leach field because over time they can compact the soil too.
- In the winter don’t remove or compact snow cover above all parts of the septic system. Snow is a great insulator and even though the ground can get cold it’s a lot warmer than the minus 10 degrees Fahrenheit air temperatures that some parts of the country experience. Snow cover will help keep the ground around the system’s components above freezing.
- Don’t put items like dental floss, flushable wipes, coffee grounds, cat litter, pesticides, cigarette butts, cotton balls or swabs, diapers, condoms, and feminine hygiene products into your septic system. Remember, it’s not a waste basket.
If you fail to do the proper maintenance on your septic system you could experience a total system failure.
Some symptoms of a failing system can include sewage surfacing over the tanks or drain field, slow drains or sewage backing up into the home.
If you experience any of these problems contact a professional and your local health department as soon as possible.
Sometimes systems can be saved from having to be replaced. By correcting small problems when they occur you prevent larger and more costly problems.
Proper understanding and care of your septic system help to protect the natural water resources we are fortunate to have.
It takes each one of us to make sure we do our part to assure that this life-giving resource remains clean and healthy for generations to come.