Frequently Asked Questions

Living with a Septic System or an Aerobic Treatment Unit.
How often should a septic tank be pumped out?
Do cleaning products affect my system?
How does a garbage disposal impact my septic system?
Why does my system backup or struggle to perform during periods of heavy rain?
Why do my spray heads continuously operate when it rains?

Are vehicles, decks, sheds or livestock allowed over the soil treatment area?
What plants are appropriate for the soil treatment area?
Do antibiotics affect system performance?
What should not be flushed down the drain?
How do septic systems and aerobic treatment units work? (Interactive tool)

Living with a septic system or an Aerobic Treatment Unit

You may not realize it, but if you have a septic system in your backyard, you are the owner of a small scale wastewater treatment system. As the owner you are responsible for maintaining a properly operating system to protect the health of you, your neighbors and the environment. A malfunctioning wastewater treatment system can release nutrients and pathogens which harm water quality and pose a threat to public safety.

The essentials for operating and maintaining a conventional septic system or an aerobic treatment unit start at the source of the wastewater stream. The occupants control the amount of water, organic material, and chemicals that enter the waste stream. A wastewater treatment system is designed to accept a specific volume of water and organic material. Exceeding these design volumes can have a significant impact on the performance of your system.

A wastewater treatment system relies on calm conditions to allow the separation of solids from the wastewater. These calm conditions are disrupted by excessive water usage or hydraulic loading. Doing several loads of laundry back to back in a single day can create a hydraulic overload and turn the calm conditions in the tank to whitewater rapids. When this happens, solids are not allowed to settle and will travel further down the system, possibly clogging pumps, spray heads, or drain fields.

Both conventional septic systems and aerobic treatment units are full of numerous microorganisms that are actively digesting and breaking down organic waste. These microorganisms are naturally occurring; therefore it is not necessary to pour additives, yeast or any other materials down the drains. Avoid excessive use of cleaners or toxic chemicals which can kill microorganisms.

The microorganisms in an aerobic treatment unit rely on the right mixture of food and air to stay alive and actively treat waste. The compressor in the yard supplies the air and the residents supply the food. A system is organically overloaded when there is more organic material than the microorganisms can treat and digest. This results in a quicker accumulation of solids and the need for more frequent maintenance. A kitchen garbage disposal can significantly increase the amount of organic loading and may reduce the pump out intervals by 1 to 2 years.

Even though an aerobic treatment unit contains a disinfection device such as an ultra violet lamp or chlorine, the water exiting the spray heads may still contain potentially harmful pathogens. Maintaining a healthy vegetative cover in the spray field will remove excess water, nutrients, and allow the final treatment processes to occur in the soil.

Being mindful of what goes down your drain is a simple yet important step in managing your septic system or aerobic treatment unit. Maintaining your system will result in higher satisfaction, improved performance and protect environmental health.

How often should a septic tank be pumped out?

Have the septic tank cleaned before sludge or scum accumulates to the bottom of the tank’s outlet device (about every 3 to 5 years). If too much sludge accumulates, solids will leave the tank with the liquid and possibly clog the soil. Sewage will then surface or back up into the house through the plumbing fixtures.

Click the table below to view the recommended pumping frequency based on septic tank size and number of people in the household.

Septic Tank Pumping Frequency

Septic tank pumpers are equipped to clean septic tanks. Only people registered with the Texas Commission on Environmental Quality may pump and transport septic tank sludge.

Do cleaning products affect my system?

Cleaning products may alter the treatment process. When choosing a cleaning product, first read the label:

  • Danger means that the chemical will kill the microbes; use it rarely or never.
  • Warning means that limited use should not affect the system much.
  • Caution typically means that the product will have little effect on the system.

How does a garbage disposal impact my septic system?

Do not use in-sink garbage grinders excessively or discard too much grease. Garbage grinders can cause sludge or scum to build up rapidly, making it necessary to clean the septic system more frequently and possibly causing it to malfunction because the wastewater is too strong for the system to handle.

My toilets do not flush during periods of heavy rain.  My spray heads always spray when it rains.  What can be done to correct this?

Divert any rainwater running off driveways, the roof and other hard surfaces away from the soil treatment area of the final treatment and dispersal component. The soil treatment area is designed to manage a specific amount of water. Rainwater could fill the system, leaving no room for wastewater. Design landscaping to carry runoff water around the soil treatment area.

Water collecting over the components can leak into them. Also, the tanks are installed in an excavation that is backfilled with material that can collect water. If the system is not watertight, the collected water can enter the system and flush sewage through the treatment system and into the yard.

  • Look at the ground over the tanks to see if a depression has developed where rainwater could accumulate. Rainwater infiltrating the system can overload the treatment components.
  • Evaluate the color and growth of grass around the tank.  Excessive growth and darker green color than the other grass in the yard indicates that the tank or piping is broken.
  • If the tank has a riser, verify that it is in good condition and properly sealed to prevent infiltration.
  • Evaluate the system performance during rainy periods: Rainwater may be infiltrating the system if there is an unexplained number of dosing cycles and/or if the spray distribution system is spraying during a rain shower.

Are vehicles, decks, sheds or livestock allowed over the soil treatment area?

Do not build driveways, storage buildings, or other structures over the pretreatment or final treatment and dispersal components. These solid surfaces prevent access to the system for maintenance, reduce the ability of water to evaporate from the soil and restrict air movement into the soil. Reduce compaction of the soil by keeping vehicles, equipment and livestock off the wastewater treatment area. Compacted soil will reduce infiltration in the soil adsorption field.

What plants are appropriate for the soil treatment area?

Maintain a grass cover over the final treatment and dispersal component. Plant warms season grasses that use more water and over-seed with cool season grasses during the winter. Grasses remove a significant portion of the water from a system, and the grass cover must be maintained. Trees also remove water and can be planted around the system perimeter. However, roots from trees planted too close to the soil treatment area can clog distribution pipes.

Do antibiotics affect system performance?

Prescription antibiotics and drugs are extremely hard on the microbes in the system. Flushing them into the wastewater system increases the maintenance.  Visit the U.S. Food and Drug Administration website for information on the disposal of unused medications.

What should not be flushed down the drain?

The toilet is not a trash can. Do not dispose of cleaning tissues, wet wipes, cigarette butts, diapers, condoms, or other trash in the toilet. These items do not degrade and result in a faster accumulation of solids that must be removed by a pump truck.

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