Septic Systems

Expert Design Saves, Initially and Over Time.

Tejas Designs & Septic Systems specializes in the design of commercial and residential wastewater systems of less than 5,000 gallons per day.

Services Provided



Frequently Asked Questions

Does the system designer make a difference?

Yes! A more experienced designer will best determine the optimal system at the
most reasonable cost for each site. Similar designs for the same site can have very different
performance records and useful life spans. One system may experience problems in as little as two years while a more appropriate, better designed system can easily provide useful service for 15 years or more. If the price point system costs $8,000 and the better designed system costs $15,000 then the more expensive system costs only $1,000 a year while the poorly designed system costs $4,000 a year. Therefore you are then looking at a full replacement cost which will undoubtedly exceed the cost of a better designed system initially.

Doesn't the regulatory process insure that all Septic systems being installed are up to code?
All systems are reviewed and inspected for minimum regulatory compliance by the State Designated Representative (jurisdictional authority). Unfortunately, this does not assure that the best possible system for a particular site is installed. A system can meet regulatory compliance and still be a very poor septic system. Typically, poor design equals unplanned and possibly major expenses for correction or replacement.

How much does a septic system cost?
Cost varies tremendously with the soil conditions, topography, and amount of use. Residential systems in Central Texas can range from $6,000 to $60,000 in extreme cases. There is no such thing as one size fits most or even an average cost. The current range for installation cost for residential systems in the Central Texas area is $10-20,000 with certain difficult areas routinely exceeding this price range. A replacement system is typically more costly than the original system or a comparable new system. Commercial systems vary even more in cost. Beware: If a cost is quoted prior to having an approved design, then it is only a guess or a generic figure.

What is a septic tank?
A septic tank is a wastewater receptacle to provide settling and anaerobic treatment to the effluent (waste water). Septic tanks were first invented in the 1,600s by a Franciscan monk. "Septic tank" is used generically (and wrongly) to describe all on-site systems. See OSSF.

What is an OSSF?
OSSF stands for on-site sewage system facility, a term which covers all types of systems. OSSF basically means any waste water system that is located on the same property as the waste water source. An OSSF is a combination of both treatment and disposal.

How many different OSSF systems are there?
There are numerous types with many variations of each type. The main treatment processes are aerobic and anaerobic. These two main systems may be combined with other processes and multiple types of disposal. Common types are: Conventional pits or trenches, Low Pressure Dose Trenches, Drip Emitters, Surface application, Mounds, Evaporates, Sand Filters, Artificial Wetlands, Bio-Filters and many others.

What type system is the best?
There is no set answer for this question. Each site can have one or more types of systems which may be suitable. The choice of system type is where an experienced designer can add critical value to making the proper selection. In general, the least complex design is the best starting point. All design possibilities should be considered and evaluated by the design professional on their individual merits, prior to making a final choice.

What is the process for getting a septic permit?
The first step is to select a designer/site evaluator. Then, exploratory holes are excavated in promising areas. The best location regarding soil and drainage is selected. A site plan and survey is needed; the more detail the better. Once this information is gathered and the use of the system or size of the house is defined, the design process begins.

When the design and associated planning materials are complete, an application is made to the regulatory agency. The review process is thirty days (for Texas) and often final revisions are required prior to approval. During this time preliminary bids for installation may be sought. Final bids are submitted once permitting is approved.

How is the OSSF sized?
The size of the system varies with type of soils, type of system, location, and waste water generation. Residential systems are based on the potential number of people in the house, which is determined by the heated and cooled square footage and the number of bedrooms (any room with a door and a closet), whichever is the greater number.

Commercial systems are based on both the volume of waste water and the strength of the waste water.

What does the "R.S." credential stand for?
R.S. stands for Registered Sanitarian. An RS is a Texas Department of Health Services registered public health professional qualified by specific education, specialized training and field experience to protect the health, safety and general welfare of the public from adverse environmental determinants. The scope of practice of an R.S. in Texas includes on-site wastewater treatment and disposal.