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Advice for an Owner of an On-Site Sewage Facility (Septic System)

Provides answers to commonly asked questions by homeowners regarding their system and tips to use in selecting an installer.

A person must hold a permit and an approved plan to construct, alter, repair, extend, or operate an on-site sewage disposal facility (or septic system).

Can I install my own OSSF? Which system should I select?

  • Have a site evaluation performed in the area where you want the disposal field built.
  • Based upon the results, select the type of treatment and disposal system. Factors to consider:
    • Initial capital cost.
    • Ongoing operation and maintenance cost—
      • maintenance contract requirements (if a maintenance contract is required, ask how much the continuous contract will cost after the first two years);
      • routine repairs; and
      • replacement of mechanical parts.
    • Expected life span of the system.
  • After you have selected your system, you must submit planning materials to your local permitting authority for the authority to authorize you to begin building.
  • Find an installer who seems to fit your requirements.
    • Interview the installer by phone and in person.
    • Ask lots of questions.
    • Obtain at least three estimates. If all are close, you have a good bid. If two are close, call the one that is not close and try to find out what the installer is missing or has added to the bid. If all three are far apart, you may want to obtain new estimates from different installers.
    • Check references.
    • Think twice before hiring the first installer you meet, or choosing the one with the cheapest estimate.
  • Work out all the details. Document every decision, selection, and location. Avoid designing as you go, which will probably result in permit violations that could cost you more money.
  • Do not pay large sums of money in advance. Texas Property Code 162.006 requires a construction trust account to be established for any amount over $5,000 when a contractor enters into a written contract with an owner.
  • Insist on good service, good manners, and sound business practices.
  • Trust your instincts and use common sense.
  • Have a third party available whom you can call on for information or a second opinion.

Most important: Keep in mind that your OSSF is not a city sewer. But treat it right, feed it properly, and it will provide efficient service. While operating your OSSF, remember these dos and don'ts:


  • Have your tank pumped and cleaned by a TCEQ registered sludge hauler. Use this table to determine how often you should have your tank pumped and cleaned (figures with a green background represent average situations):

      Household size (number of people)
      1 2 3 4 5 6 7 8 9+
    Tank Size (gallons) Duration (in years) Between Pumpings or Inspections
    750 9.1 4.2 2.6 1.8 1.3 1.0 0.7 0.6 0.4
    1,000 12.4 5.9 3.7 2.6 2.0 1.5 1.2 1.0 0.8
    1,250 15.6 7.5 4.8 3.4 2.6 2.0 1.7 1.4 1.2
    1,500 18.9 9.1 5.9 4.2 3.3 2.6 2.1 1.8 1.5
    1,750 22.1 10.7 6.9 5.0 3.9 3.1 2.6 2.2 1.9
    2,000 25.4 12.4 8.1 5.9 4.5 3.7 3.1 2.6 2.2
    2,250 28.6 14.0 9.1 6.7 5.2 4.2 3.5 3.0 2.6
    2,500 31.9 15.6 10.2 7.5 5.9 4.8 4.0 3.5 3.0
  • Obtain information on conserving water from your water supplier.
  • Check your toilet for leaks periodically. Add a water-based dye to the flush tank and see if the dye appears in your toilet within 10 minutes (without flushing the toilet).


  • Build over any part of your on-site sewage disposal system. Examples of items not to construct over your system: driveways, barns, storage buildings, sidewalks, and patios.
  • Add chemical additives or the so-called enzymes into your OSSF. Some of these additives may even be harmful to the tank's operation.
  • Use the toilet to dispose of cleaning tissues, cigarette butts, or other trash. This disposal practice will waste water and burden the treatment system with an undesirable load of solids.
  • Drive or park vehicles over the OSSF.

First, determine what is causing the failure. Common causes are:

  1. Hydraulic overloading
    • To determine if your system is hydraulically overloaded, check your water usage records and compare the average gallons used per day with the amount specified in the system design.
      • If you are using more than what was designed, your system is hydraulically overloaded. You will need to reduce the amount of water being discharged into your OSSF.
      • If your water usage is less than the design, procedure to the next item.
  2. Misidentification of soil or site conditions
    • Before February 4, 1997, the most common way an OSSF was designed was based on percolation tests. Unfortunately, the percolation test did not address any limiting factors to a depth of two feet below the bottom of the drainfield or address the soil texture in the disposal area.
    • Subsurface water flow within the disposal field, subsurface restrictive horizons below the disposal field, or seasonally saturated soils will cause OSSF failure and requires corrective action by the property owner.
  3. Organic overloading
    • This most commonly occurs where food is prepared. A five-day biochemical oxygen-demand test would need to be run on the effluent (wastewater leaving the septic tank).
      • The rules assume the five-day biochemical oxygen demand (BOD5) of the effluent to be 140 mg/l.
      • If there is a large amount of food, grease, or the like leaving the facility and entering the septic tank, the disposal field is most likely organically overloaded.
  4. Poor maintenance
    • A septic tank should be pumped every three to five years.
    • A system using secondary treatment or drip irrigation must be inspected by a valid maintenance company once every four months, or be maintained by the single family homeowner, where allowed.
  5. Age
    • If your OSSF is more than 15 years old, the system may need to be replaced.

If an existing OSSF, regardless of the date of installation, is required to have a tank replaced or a drainfield repaired (or replaced), a permit is required by 30 TAC 285.3

If the tank can be repaired without having to remove the tank, the work is considered emergency repair and a permit is not required. However, the work must be reported to the permitting authority within 72 hours after repairs have begun. For a disposal area, any work would require the system to meet the current standards.

Your mortgage company may require an evaluation of your OSSF before completing the sale. This type of evaluation is not required or regulated by TCEQ. If you have a problem with the inspection, contact your mortgage company or the Texas Real Estate Commission.

  • Your mortgage company may require an evaluation of your OSSF before completing the sale. This type of evaluation is not required or regulated by TCEQ. If you have a problem with the inspection, contact your mortgage company or the Texas Real Estate Commission.
  • Once you purchase the home, notify the local permitting authority that you are the new owner of the OSSF and ask about the proper startup procedures for the OSSF.