Septic System Backs Up

Problem: Wastewater from on- site sewage system backs up into home sewer lines or seeps to the ground surface.

Background: Common problems in private sewer systems are under sized drain fields, undersized septic tanks, and poorly maintained septic tanks (which cause clogged dry- wells or drain fields). Adequate drain field size depends on soil type and amount of sewage treated. If the ground above the drain field is especially wet or soggy, or if the capacity of the tank is too small, the system may be inadequate. A 1,000-gallon septic tank is considered a minimum for 3-bedroom homes; 1,250 gallons for 4-bedroom homes, and 1,500 gallons for 5-bedroom homes.

 

What to do: All septic tanks periodically need to have sludge and scum solids removed, depending on their tank size and the daily load discharged into them. Some tanks need to be pumped out every 2 years, but others may need it only once every 10 years. (Homeowners who claim they never have pumped out their septic tanks probably have an in complete system that doesn’t have a leaching field and discharges directly into ditches, streams, lakes, or agricultural drain tile lines.) Tanks should be inspected annually to see if pumping is necessary. A probe with a 3-inch square-shaped foot can be used to check the level of the scum layer. If the bottom of the layer is within 3 inches of the bottom of the outlet tee, or baffle, the tank should be pumped out. A pole with an old bath towel wrapped around the bottom 3 feet can be used to measure the sludge depth. Pump out tank if sludge is within 12 inches of outlet tee, or baffle. Note: Chemical additives are not needed for proper sep tic tank operation and, in some cases, can harm the tank.

Special advice: After pumping out, the condition of the tank’s inlet and outlet tees, or baffles, should be inspected and replaced if damaged. Never enter, or allow anyone else to enter, a septic tank unless a continuous supply of fresh air is pumped into the tank and a strong rope is attached to the person entering the tank. Adequate help should be available at all times in case it becomes necessary to lift a person out of the tank. Maintenance of the leaching field is limited to checking the distribution box or drop boxes twice a year. (Drop boxes provide a simple method of distributing flow on sloping sites. If used, inlets to the most heavily loaded trenches can be blocked off for 6 to 12 months to overcome effects of unbalanced loading.) There is no need to wash or disinfect a tank after pumping. It is also not necessary to leave some sludge in the tank, or add special chemicals, to get the tank started after pumping.

Helpful hint: Septic tanks are de signed to trap and store solid materials, not carry them away. To avoid sludge build-up or clogged sewer lines leading to the tank or the tank’s inlet and outlet parts, do not flush items such as cat litter, rags, sticks, plastic disposable diaper linings, high-strength paper products, and other nondecomposable products into the system.