Onsite Septic



Distribution box

Soil Scientist examines the soil



Frequently Asked Questions*

1. How often should my tank be pumped? Is there a difference between pumping and cleaning?

As a rule, tanks should be checked for solids buildup every year and pumped every three years to five years, more often if you have a garbage disposal. It is best not to wait until the plumbing system begins to back up in your home. If solids overflow from the tank, some very expensive damage can be done to the soil absorption system.

In practice, however, how often solids should be removed depends on the lifestyle of the family using the system and the size of the tank. For example, a garbage disposal can result in a rapid buildup of solids. Many homeowners have installed risers with child-proof caps on their tanks to simplify removal of solids and they routinely have their tanks cleaned every three to five years.

When choosing a company to remove solids from your tank, ask if they thoroughly clean the tank and remove all solids. It is not very useful to just pump the liquids without removing the solids from the tank. Reputable companies flush removed liquids back into the tank to thoroughly agitate and remove settled solids. In addition, they check the baffles on the tank to make sure they are functional and clean the tank’s effluent filter (if installed).

If your tank has an effluent filter installed, inspect it via the riser every 6-12 months for fouling. If buildup on the filter becomes substantial, have the tank cleaned. A properly functioning tank effluent filter protects the soil absorption field much more effectively than a baffle. If your tank does not currently have one, consider installing one the next time you have your tank cleaned.


2. Do I really need to protect the area where the septic system will be before constructing my home, as well as after installation?

Soil is the most expensive and important part of the septic system. As such, a homeowner should protect the soil absorption field before and after installation.

All Indiana septic systems must discharge into the soil. For soils to be suitable for a septic system soil absorption field, they must not be compacted. Compaction reduces the ability of a soil to disperse and treat wastewater effluent and can lead to system failure, and a costly repair. The more natural and undisturbed the soil on your lot, the better your septic system is likely to perform. Do not put any structure on top of or 50 feet downslope of the soil absorption field either. It is also a good idea to maintain another area on the lot for another soil absorption field in case the system fails.


3. How can I prevent system failure?

If the system has been properly sited, designed and installed, the rest is up to you, the homeowner to see to the maintenance.

In addition to routinely having solids removed from the septic tank, the soil absorption system can be damaged by excess water wastage in the home, exceeding the soil’s ability to absorb it. Either situation can result in long-term damage to the system.

Homeowners with septic systems must also be more careful about what they flush down the drain than their urban neighbors. Never pour substances such as motor oil, gasoline, paints, thinners, or pesticides down the drain. These materials pollute the groundwater and are often toxic to the organisms in your tank and soil that breakdown your wastewater. Likewise, fats, grease, coffee grounds, paper towels, sanitary napkins, disposable diapers, and other such items can clog your septic system. Moderate use of household cleaners, disinfectants, detergents, or bleaches do little harm to the system, but avoid excess use.


4. How long will my system last?

Many septic systems in Indiana last 20 years or more. On the other hand, if the system is not properly sited, designed, installed and maintained, it may have a life of only a few months or years, and be very difficult and expensive to repair or replace. Septic system failure can also result in a public health and water quality threat. Consequently, there are regulations in place at both the county and state level in Indiana that are intended to minimize septic system failures.

5. If I have a problem, what repairs can be done and who should do them?

If you have a septic system problem, you should contact the county health department. They should have a list of professionals who work in your county. You can also check the Indiana Onsite Wastewater Professionals Association. This organization lists the contact information of professionals throughout the state.

6. Will trees and tree roots affect my system?

Roots from trees and shrubs can invade and plug sewer lines. Wastewater effluent is full of plant nutrients including nitrogen and phosphorus. Roots are attracted to leaking septic tanks and to absorption fields to obtain these nutrients. Roots can seriously damage septic tanks and distribution pipes resulting in significant repair costs.

If you do have trees near your soil absorption field, they should be as far away as possible from the entry point of effluent to the drain field. Trees should be planted at least as far away as their estimated root spread at maturity. One way to estimate this is by the ultimate height of the mature tree. For example, a weeping cherry may be expected to grow about 25 feet tall, and should be planted a minimum of 25 feet away from the drain field. A mature oak might need to be 60 or 70 feet away.

While trees do remove a significant amount of water from the area, avoid planting water-loving trees such as willow and poplar near the soil absorption field. If you are willing to risk some root intrusion, non-aggressive species can be placed near to the drain field (although closer than 10 feet is not recommended). Although the root spread of non-aggressive species trees may eventually encompass a portion of the drain field, the roots are not likely to cause serious damage to the distribution lines because the
lines are surrounded by gravel. Still, the potential for damage to the system exists. 

* Adapted from a Purdue publication.

For more information, contact  Randy Pease at (317) 346-4371 or rpease@co.johnson.in.us .