It is vital that people who have OSSFs or plan to buy property that has or will have an OSSF understand the type of system, how it works and how to properly use and maintain it.  Our inspectors have provided answers to the frequently asked questions listed below.

Who inspects or approves my OSSF?

The entire state is under the authority of the Texas Commission on Environmental Quality (TCEQ) and they delegate authority to local governments.  In Tarrant County the only authorized people are Tarrant County (we have contracts to do the work for most of the cities in the county), the Tarrant Water Improvement District (only within 2000 feet of Lake Eagle Mountain) the City of Arlington and the City of Fort Worth Lake Management in certain areas around Lake Worth.

What does an OSSF do?

Any sewage treatment facility must receive the wastewater and sewage from the source (a home, business, etc.) and dispose of it in a safe and sanitary fashion to prevent the spread of diseases or other negative health effects.  Sewage consists of liquids and solids with liquids making up the majority. In its simplest form, a disposal system does two things: 1) the solids are removed and 2) the liquids are disposed of by soaking into the soil or evaporating into the air.  How well the solids are removed, how much liquid is left and how well the soil can dispose of the liquid are the vital criteria for determining the type of system to be used.

Do all systems dispose of liquids into the soil?

No.  Some special designs and recent technology allow alternatives.  If it doesn't go down into the ground it probably evaporates into the air.  That is where technology can help by treating the water to a point where it can be disposed of at the surface.

If I can flush my toilet does that mean the system is working?

That is only one piece of a working system.  After the sewage leaves the house, is it disposed of properly?  Unfortunately, many people have had systems that "worked" only to find that the pipe ended in the creek and their sewage was creating a health hazard.

I can flush and no sewage comes out on the surface, is it working?

Those are two of the three factors that are needed for a standard septic system to be "working properly."  If there is groundwater very close to the bottom of the system or if there is a way for the sewage to reach the groundwater (through cracks or fissures in rock under the system) the system could still be polluting ground water.

How do I know what is happening underground, I can't see where the sewage goes?

A lot of research has been done through the years that let us understand what happens to the sewage once it enters the ground.  Under current regulations, before any sewage is disposed of into the soil, tests must be performed that detail the soil conditions for at least two feet below the bottom of the disposal system.  Unfortunately, a lot of older systems were put in without adequate knowledge, so it is difficult to tell.

What do I have to do to put in a system?

Basically, you get a site evaluation performed and submit the report with an application and fees.  We will set the minimum specifications.  Then you (or your installer) will submit a plan, we approve it (hopefully), it gets constructed, we inspect it and you are done.  For more details, see the OSSF Permit Packet on the main page.

Who can install an OSSF?

A state licensed installer or a homeowner, provided that it is a single family residence.  For multi-family, rental property, or nonresidential property, the licensed installer is required.  A copy of OSSF Rules and Regulations is available on our main OSSF page.

What is an aerobic system as compared to a septic system?

An aerobic system is different from a septic tank.  In a septic tank, the bacteria use up any dissolved oxygen in the water and then get oxygen by breaking down the sewage.  Septic means no dissolved oxygen and that the bacteria are making their own oxygen.  At the same time they make other gases that smell, hence the characteristic odors.  In an aerobic tank, air is forced into the water and a whole different group of bacteria are able to exist.  These aerobic bacteria don't give off odors, are generally not as dangerous and do a much better job of "eating" the sewage solids.  The effluent is much cleaner coming out of an aerobic system, but it is still not safe.  Because it is cleaner, we can treat the effluent to kill any dangerous organisms and then dispose of the treated effluent in a variety of ways.

Can I dispose of aerobically treated effluent on the surface?

Not without some additional steps.  If you use an approved unit (they are very thoroughly tested) and you add a disinfectant stage (probably a chlorinator) you can dispose of it on the surface of your property.  The system must be designed for this purpose and it must have an on-going maintenance contract that includes periodic testing to be sure it is operating properly.

What should I do to maintain my septic tank?

You should: 1) make sure you don't waste water, check for water leaks, don't leave water running, 2) don't use the toilet as a trash can and minimize the use of a garbage disposal - if you can't digest it neither can your septic tank, 3) make sure you keep the disposal field free of excess runoff water, fill in low spots, redirect drain spouts, 4) have the tank(s) pumped out every two to five years.

What about additives for the septic tank?

Don't waste your time or money.  People put yeast, cow manure, or various compounds bought at the store in their system, but they don't do much of anything.  Remember, every time you send waste to the tank you are sending bacteria.  These bacteria have established a very concentrated mixture in the tank(s) and you aren't going to change it easily.  Any chemicals that are strong enough to change your system may cause damage or build up in the soil and cause long term problems.

What about additives for an aerobic tank?

Under no circumstances should you add anything other than standard household waste or manufacturer approved products.  An aerobic tank is very carefully designed and chemicals or additives can completely destroy the bacterial culture that is the essential treatment element.

How much land do I need to put in my sewage facility?

This is not an easy question to answer.  Our experience shows that anything less than an acre can be difficult (that's a recommendation, not a requirement).  The general state minimums are one acre for land with a water well and sewage facility, or 1/2 acre for land with only a sewage facility.  The size requirements of a piece of property apply when it is divided.  If you have an existing piece of land smaller than the above, then you must submit a professional design showing how you can get a legal system on your property.  No matter how big or how small, each piece of property will be evaluated individually.  A person with 2 acres might not have enough if they have a well, stock pond, creek, big house, garage etc.  Be sure to read the next question.

I'm splitting up a piece of land, how small can I make it?

If you will have On-Site Sewage Facilities, the state law has two possibilities -- you will need one acre if you might have a well, or one half acre if you will only have a public water supply.  However, you must have enough land to meet the requirements for the system you need.  Now to make it even more involved, cities can have requirements outside their city that may affect the minimum size.  These city rules exist under the authority of Extra Territorial Jurisdiction.  Most of Tarrant County is covered by Fort Worth's ETJ and they make it simple by requiring a minimum of one acre.  Remember, old, existing, recorded property is treated on an individual basis.

I want to subdivide some land, who do I need to talk to?

If you are within a city, then that city will have authority.  If you are in the unincorporated area of the County you will deal with the Health Department, Transportation Department (817-884-1250), and if you are within the Extra Territorial Jurisdiction (ETJ) of a city, they will also be involved.  Fort Worth's ETJ covers most of Tarrant County but call us if you are not sure.  The City of Fort Worth Development Department can be reached at 817-392-2497 should you have any questions.

What is the On-Site Sewage Facilities Fee Schedule?


Application and Permit (includes State fee)                             




Repar Permit




Affidavit (filed at County Clerk’s Office)


   $19 for the 1st page

$4 for each additional page