Septic tanks may have one or two compartments. Two compartments tanks do a better job of settling solids & may be required for new systems. Tees or baffles are provided at the tank's inlet & outlet pipes. The inlet tee slows the incoming wastes & reduces disturbance settled sludge. The outlet tee keeps the solids or scum in the tank. All tanks should have accessible covers for checking the condition of the baffles & for pumping both compartments. If risers extend from the tank to or above the ground surface, they should be secure to prevent accidental entry into the tank.

Solids that are not decomposed remain in the septic tank. If no removed by periodic pumping, solids will accumulate until they eventually overflow into the drainfield, leading to costly repairs or replacement. Remember that retention time, or the time available for solids to settle out of wastewater, decreases as the sludge layer increases in your septic tank.

Maintenance
Most septic tanks must be pumped once every three to five years, depending on tank size, number of persons in the household & whether or not occupants are minimizing release of unnecessary solids into the wastewater.

How do I determine when to pump?
Many homeowners prefer to give this responsibility to a reputable septic tank pumping firm. They will periodically check your system to determine the rate of solids accumulation & proceed w/ a pumping schedule designed for your specific situation. Some homeowners may wish to measure sludge depth & scum thickness themselves, using a homemade probe. Guidelines for performing this messy operation may be obtained from your local sanitarian in the county health office. The tank requires pumping if: a) the top of the sludge deposit is w/in 12 inches of the outlet baffle; b) the bottom of the floating scum mat is w/in three inches of the bottom of the outlet baffle; c) top of the floating scum mat is w/in one inch of the top of the outlet baffle or; d) the floating scum mat is more than 10-12 inches thick.

Should I use any special products to enhance the operation of my septic tank?
Many products which claim to improve septic tank performance or reduce the need for routine pumping are available. These solvents, yeast, bacteria, & enzymes have not been found to make a significant difference.

Some can even cause solids to be carried into the drainfield, causing early clogging & repair. Some products contain organic solvents which contribute to groundwater pollution.

Where is my tank located?
If you do not know where your septic tank is located, you can find it by gently tapping a steel rod into the ground starting about 10 feet from the point where the sanitary drain leaves the house. Another method is to wait for a light snowfall. The snow is likely to melt first directly over the septic tank.

THE DRAINFIELD
The drainfield receives septic tank effluent. It has a network of perforated pipes laid in gravel-filled trenches (two-three feet wide) or beds (over three feet wide) in the soil. Wastewater trickles out of the pipes, through the gravel layer, & into the soil. The size & type of drainfield depends upon estimated daily wastewater flow & soil conditions.

The soil below the drainfield provides the final treatment & disposal of the septic tank effluent. After the effluent has passed into the soil, most of it percolates downward & outward, eventually entering the groundwater. A small percentage is taken up by plants through their roots, or evaporates from the soil.

The soil filters effluent as it passes through the pore spaces. Physical & biological processes treat the effluent before it reaches groundwater, or a restrictive layer, such as hardpan, bedrock, or clay soils. These processes work best where the soil is somewhat dry, permeable, & contains plenty of oxygen for several feet below the drainfield.

Warning Signs of a Failure

• odors, surfacing sewage, wet spots or lush vegetation in the drainfield area
• plumbing or septic tank backups
• slow-draining fixture, not due to local clogging
• gurgling sounds in the plumbing system

If you notice any of these signs or if you suspect problems w/ your septic tank system, contact your local health agency for assistance.

Recommendations to prolong the life of your septic system to minimize maintenance costs:

Do
1) Inspect for scum & sludge depth once each year & never allow sludge or scum to escape from the septic tank into the drainfield.

2) Pump tank at proper intervals (usually every three to five years).

3) Limit water entering your tank:

• use water-saving fixtures (faucets, showers, toilets)
• prevent basement sump pump connection to tank
• drain appliances one at a time
• spread clothes-washing over the entire week & avoid half-loads
• prevent roof, foundation, driveway & basement drainage from entering tank or drainfield area
• minimize amount of water used for bathing & dishwashing
• fix all faucet & toilet float valve leaks

4) Keep soil over your system slightly mounded to help surface water run off.

5) Landscape your system properly. Dense grass cover & other shallow-rooted plants are beneficial over a drainfield.

6) Keep automobiles, all heavy vehicles & livestock off the drainfield.

7) Mark the boundaries of your drainfield as a reminder.

8) If your system is equipped w/ a diverter valve between the septic tank & soil absorption field, allow one side of your system to "rest" at one-year intervals.

9) If your system is equipped w/ a dosing chamber, be sure the submersible pump is operating & properly maintained for uniform discharge of effluent into the absorption field, followed by drainage between doses.

Don't
1) Use chemicals to clean or "sweeten" your system except on the advice of your local health department.