There are several different types of septic systems in use today.  The characteristics of your property determined what type of septic system was installed. The soil conditions; such as absorption rate, type of soil and how much soil is present, were a major factor in deciding what type of system was installed.  In addition, the water table level and the grade elevations of the property also played a role in that decision. Knowing what type of septic system you have, as well as it’s location is an important part in your responsibility to keep the septic system running efficiently and effectively. Following the  “Septic Dos & Don’ts  and performing the   “Maintenance and Pumping”   at the appropriate intervals, will reduce the chances of septic system failure which can be very costly.

The content on this page will be better understood if you are familiar with the operation of a  basic septic system. If you haven’t done so, please visit our  “Septic Systems”    page and take a couple of minutes to familiarize yourself with the 3 main components of a basic septic system.

A Standard Gravity System is used when you have ideal conditions. Effluent from the Septic System gravity flows directly from the septic tank to the drain field without the aid of any pump. The soil has very good absorption characteristics and can handle the effluent from normal use being introduced into the drain field. The soil also has good treatment quality, in a sufficient amount above the water table to effectively purify the waste water before it enters the water table.

An Evaporative System is used when the soil cannot treat the waste water before it percolates to the water table. This occurs usually in rocky or sandy soils which drain to fast or where the soil absorption is very poor as you would find in heavy clay soils. An evaportanspiration (ET) bed treats the water by using evaportranspiration, which is the loss of water in the soil by both evaporation and transpiration from the plants growing there. The evaportranspiration bed is shallow and can be lined with a liner or unlined. A liner is required if the soil drains so fast the water can’t be treated before it hits the water table. In clay soils the ET can be unlined which also allows disposal through some absorption in the soil. These are often called evaportransition/absorption beds (ETA)

A Sand Filter System uses a bed of sand between the septic tank and the drain field. Sand filters have been used where conventional septic tank/absorption field systems have failed. They are a good option for sites with high groundwater, shallow bedrock, poor soils, or other restrictions. A typical sand filter is a line watertight box filled with sand. The effluent from the septic tank is introduced into the sand bed uniformly through controlled doses through a network of distribution pipes placed in a gravel bed located above the sand filter. As water trickles through the sand bed, it is filtered and collected at the bottom. The sand bed also is a biological filter using micro-organisms to decompose the waste water (a type of aerobic system) This water is then sent to the soil absorption field either through standard gravity or a pump system. The discharge pump chamber may be located in the sand filter.

A Dosing System introduces the effluent waste water from the septic tank to the drain field in intermittent intervals (doses) throughout the day. This allows the soil to absorb the “dosed” water in the drain field before more water is introduced.   These types of systems are used in soils with poor absorption rates or shallow soils.  There are two common types of dosing systems: The Siphon Dose and the Low Pressure Dose.  A siphon dose system (not pictured) does not use an electrical discharge pump. It uses a siphon bell ( an inverted bell that is open on the bottom and traps air) that cycles as the water level rises and cause the effluent to dose into the drain field by a siphon action  (Click on the link  ◄ to the left to see how it actually works). A low pressure dosing system uses a pump in a pump chamber (as shown in picture on the left). The pump turns on intermittently through electronic controls  and sends the effluent  to the drain field in intervals throughout the day.

Orenco Systems has a Textile Filter System call Advantex®. This type of treatment system has advanced secondary waster water treatment using Orenco’s textile filter technology. The effluent is pumped to a filter chamber in periodic intervals that are configured within the controller to meet the owner’s typical usage. The effluent is uniformly sprayed over the filter media. The effluent out a AdvanTex® System is so clean and odorless that in some jurisdictions it can be used for drip irrigation.  Once the water is treated it is sent to the drain field in doses. Advantex® Treatment Systems can be provided with Orenco’s  Vericomm ® Control Panel.  Vericomm® is a secure Web-based 24/7 monitoring system with automatic communication of all alarms and system status. Foothill Sanitary is a Certified Orenco Provider for AdvanTex® and Vericomm® Systems. Click on the video link on the left to see how the  AdvanTex®Treatment System works. The pdf link will open up the Vericomm® Monitoring Brochure

Aerobic Treatment Systems (ATS) or Areobic Treatment Units (ATU) are often incorrectly called an “Aerobic Septic System”. An Aerobic Treatment System is actually a small sewage treatment plant which uses an aerobic process for digestion. Septic tank systems utilize an anaerobic process. To put it in simple terms: Aerobic bacteria requires oxygen to thrive and remain alive while anaerobic bacteria does not rely on oxygen for metabolic processes and survival. The Aerobic Treatment Systems/Units are typically comprised of 3 chambers. The first chamber, (commonly called the pre-treatment or storage tank) collects the solids and paper products. The second chamber is called the aeration chamber. Air is forced into the chamber and mixed with the waste water. The oxygen breaks down the organic matter rather quickly. The third chamber is the pumping or dosing chamber that removes the treated liquid for dispersal to the soil. ATUs require electricity 24/7 to power the aeration system (typically air pump).

A good site to visit for several educational videos regarding septic systems can be found on Washington State’s Department of Health On Site Sewage Systems Home Owner Education Page. The Full video course is 5 chapters and runs 19:02 minutes. You can watch the individual chapters by themselves which range from 2:29 to 6:57 minutes in length. Chapter 3 – Types of Septic Systems is 6:57 minutes and goes over most of the systems described on this page.

Septic Systems are Engineered by a Licensed Engineering Company. We at Foothill Sanitary Septic highly recommend Cal State Engineering in Jackson, CA as they are the best. Please feel free to click on the link to their website for further information
” Tell Them Kevin of Foothill Sanitary Sent You ”