Wastewater Disposal Facts


When a septic system, pressure dosing system, or an aerobic spray irrigation system is installed, it is not wise to add softener backwash to the sewer system. Water is what causes septic systems to fail in most cases. The septic system does not need the extra burden of this backwash. In addition, all of the available literature suggests softener backwash not be added to a septic system. The manufacturers of aerobic systems all state that water softener backwash should not be put in this type of sewage treatment system. The bacteria in an aerobic system are required to recycle wastewater, and they do not thrive well in salty environments. Therefore, adding salty backwash to an aerobic plant reduces its capacity and may lead to odor problems.


So, what should be done with the backwash from a water softener? The backwash from a water softener does not cause a health hazard when discharged on the surface or in a drainage ditch. Some people even dig a pit to discharge this salty water under ground. We recommend that this water be disposed of by some means other than through a home sewer system.



On humid days each air-conditioning unit can add 15+ gallons to an on-site sewage facility (OSSF). For an aerobic spray irrigation system, about the only evidence of this load will be a little more water on the grass. It is our professional opinion that this extra water will actually benefit the grass with no downside. However, any additional water into a conventional septic system will shorten the overall life of the field in proportion to the percentage increase of water into the system.



The TNRCC allows the water from a washing machine to be discharged without treatment (even surface discharged). Diverting this water from a septic system can have a major positive affect on the life of the system. For aerobic spray irrigation, we recommend putting this water through the sewage treatment plant and spraying it on the yard.



Grey water is defined as wastewater that does not contain human waste or food particles from food preparation areas, i.e. bath water from a shower/tub, lavatory water, etc. Water from a kitchen sink or dishwater is not considered grey water. Grey water, other than that from washing machines, must be disposed of in the same manner as "black" water.