General Information

The Basics

What is a septic system?

An On-Site Sewage Facility, commonly called a septic system, is a method of waste disposal that uses natural processes to treat and dispose of the wastewater generated in your home. A septic system typically consists of a buried tank and a drainfield or soil absorption field. The septic tank is the first step in the wastewater treatment process. As wastewater flows into the tank, the heavier solid materials settle to the bottom forming sludge. The lighter solids, greases, and oils float to the top forming a layer of scum. The liquid wastewater (effluent) then flows out of the tank into gravel filled trenches or is pumped through spray heads onto the spray absorption field. The effluent is then treated in the soil through natural biological processes.

The septic tank provides some biological treatment of the sludge and scum layers that accumulate within. The majority of treatment occurs in the drainfield where the effluent enters the soil and is treated as it percolates through the soil to the groundwater. The soil acts as a biological and physical filter removing harmful substances, such as disease-causing bacteria and viruses, toxic organics, and other undesirable wastewater constituents contained within the effluent.

The Types

There are several types of On-Site Sewage Facilities. View these documents in Google Drive to see a brief description and diagram of each type of system.


Though a septic system is designed to handle waste disposal and conduct treatment of those wastes, the system must be properly maintained. Proper maintenance of a septic system includes maintenance contracts, regular inspections, pumping, and day-to-day management. The more you know about how your system operates and how it should be maintained, the better you will be able to protect your investment in your home and property, protect your family's health, and protect your environment.

Maintenance Contracts, Inspections, & Pumping

If your septic system is a secondary (aerobic) system, you will need an ongoing maintenance contract. This is a contract between you, as the homeowner, and a registered septic maintenance provider. Please go to the website for the Texas Commission on Environmental Quality for a comprehensive list of on-site sewage facility installers and aerobic treatment system maintenance providers. Systems are required to be inspected at least three times per year. Copies of maintenance contracts and inspections must be submitted to the local regulatory authority.

If your system is a conventional system, an ongoing maintenance contract is not required. However, the system does need to be inspected on a regular frequency to check sludge and scum levels.

If your inspection shows high levels of sludge and scum, the tanks will need to be pumped to ensure they continue to operate normally. Contact your maintenance provider for more details.

Maintenance Tips and Recommendations.

See also "Septic Guidelines (PDF)"
  • An OSSF should not be treated as if it were a normal city sewer system.
  • Chemical additives are not necessary for the operation of a septic tank. Some may even be harmful to the system.
  • It is not advisable to allow water softener back flush to enter into any portion of the OSSF.
  • In-sink garbage grinders can cause a rapid buildup of sludge or scum resulting in a requirement for more frequent cleaning and possible system failure.
  • Septic tanks shall be cleaned before sludge accumulates to a point where it approaches the bottom of the outlet device.
    * A regular schedule of cleaning the tank at two to three year intervals should be established. Commercial cleaners are equipped to readily perform the cleaning operation. Owners of septic tank systems shall engage only persons registered with the Texas Commission on Environmental Quality (TCEQ) to transport the septic tank cleaning.
  • Use Soaps, detergents, bleaches, drain cleaners, and other household cleaning materials in moderation.
    * The liquid from the OSSF is still heavily laden with bacteria. The surfacing of this liquid constitutes a hazard to the health of those that might come into contact with it.
  • Use washing machine sparingly.
Even with proper maintenance, a septic system can fail. By recognizing the signs early, potential failures along with environmental hazards and financial woes can be minimized. Below are some key factors in recognizing system failure, what to do in the event of a failure, storm-water concerns, and water conservation measures.

Signs and Symptoms of Failure

  • Water backing up into the house or yard: If there is more water entering the septic system than the system can handle water can/will back up into the easiest places, such as homes and yards.
  • Foul odors: Foul odors can be an indicator of septic failure or malfunction. If foul odors are noted in the drain or application field, around the tanks, etc, contact your licensed maintenance provider immediately.
  • Damp or wet areas: Pooling or ponding areas of water in the drain field, spongy, bright, green grass in the area of the drain field or spray heads could be a sign of a damaged or failed drain line or damaged spray heads. Many times this can be caused by driving or mowing over the area and damaging the lines or spray application heads.
  • Alarm sounding: At the point of failure, alarm notifications will be triggered on the control panel. This is a definite sign that the system is in need of maintenance or repair.
Regular, routine maintenance and inspections, including regular pumping and cleaning, help to reduce the likelihood of system failure.

Water Conservation Tips
One key factor in preventing the failure of a septic system is not overloading the system with unnecessary water. Please view our water saving measures (PDF).