Site Evaluation

The site evaluation is the second step in the septic design process which is usually done in conjunction with the consultation for cost savings. Site evaluations are not only needed but they are also required by Texas law and must be performed by a site evaluator or professional engineer that is licensed by the state of Texas. The site evaluation plays a very important role in determining the potential limiting characteristics of the property such as the lot size or the soil type since they both play a major role in determining the type of septic system that might be allowed. The purpose of the site evaluation is to limit or prevent certain types of septic systems although the reason isn’t always clear. The purpose of the site evaluation isn’t to inconvenience the property owner or cost them more money but rather to protect the safety of the public and the neighbors that might be negatively affected. This same process is what protects you and your property from the neighboring properties that surround you.

Lot characteristics are somewhat complicated. Different lots have different critical characteristics. For instance a small lot may have the most critical parameter be that of size which may influence the type of system that can be utilized. For other lots that are large but that partially or entirely lie within the flood plain it may be the flood plain elevation that may dictate which type of septic system can be used. In certain cases it might even be the neighboring lots that dictate the type of septic system since state and local authorities often specify separation distances that must be maintained between the feature and septic system components. One item at the top of the list is a water well. Even if the water well resides on the neighboring property there is still a minimum separation distance that must be met which will also depend on the type of well.

There are many factors that influence the design of the septic system.  The site evaluation form has several items such as these listed below that are a big factor in the design:

  • The size of the lot.
  • The slope or grade of the lot.
  • If the lot is covered by woods or if it is covered by vegetation.
  • Whether or not there is access to city water or if the lot does or will have a private water well.
  • If there are pre-existing items that require separation from the septic tanks or the effluent field such as:
    • Pools
    • Ponds
    • Creeks or water ways
    • Driveways
    • House(s)
    • Outbuildings
  • Property easements.
  • Flood zone status.
  • Wells on neighboring properties that are within 150 feet.

There are many types of things that need to be documented in the site evaluation. You can find the minimum requirements on the Texas Commission of Environmental Quality (TCEQ) website.