SEPTIC DO'S
SEPTIC DO NOT'S
Do keep your septic tank cover accessible for tank inspections and pumping.
Do Not Flush sanitary napkins, tampons, disposable diapers, condoms, wipes, or cat litter.
Do have your tank pumped regularly and checked for leaks and cracks.
Do Not dump solvents, oil, paints, thinners, disinfectants, pesticides, medicines, or poisons down drains.
Do divert down spouts and other surface water away from your drain field.
Do Not dig in drain field or build anything over it.
Do call a profesional when you have a problem.
Do Not drive over your drain field or compact the soil in any way.
Do conserve water to reduce the amount of waste water that must be treated and disposed.
Do Not plant anything over you drain field except grass.

Common Septic Problems
1. TOILET GURGLING OR FLUSHING SLOW
A. TOO MUCH PAPER AT INLET BAFFLE
B. TANK IS OVER FULL
SOLUTION: HAVE SEPTIC TANK SERVICED
2. WATER COMING OUT OF MY VENT PIPE ON THE TANK
A. LINE FROM THE TANK TO DISTRIBUTION BOX PLUGGED
SOLUTION: DO BOX AND BAFFLE REPAIR.
B. SEPTIC FIELD IS BACKING UP
SOLUTION: REPLACE FIELD
3. WATER IS STANDING IN THE YARD
A. SEPTIC FIELD IS OVER FULL
SOLUTION:REPLACE SEPTIC FIELD

Estimated Septic Tank Pumping Frequencies (In Years)*
Tank Size (Gal.)
Household Size (Number of People)
1
2
3
4
5
6
7
8
9
500
5.8
2.6
1.5
1.0
0.7
0.4
0.3
0.2
0.1
750
9.1
4.2
2.6
1.8
1.3
1.0
0.7
0.6
0.4
1000
12.4
5.9
3.7
2.6
2.0
1.5
1.2
1.0
0.8
1250
15.6
7.5
4.8
3.4
2.6
2.0
1.7
1.4
1.2
1500
18.9
9.1
5.9
4.2
3.3
2.6
2.1
1.8
1.5
Note: More frequent pumping is needed if garbage disposal is used.
*Data provided by Oregon State University Extension Service

A septic tank is a concrete, steel, plastic, or fiberglass tank that is buried in the yard. A tank can hold 1,000 gallons of water or more, depending on the size, which is generaly determined by the number of bedrooms in your home. Wastewater flows into the tank, where scum and sludge seperate, and cleaner water leaves the tank on the other side. Below is a split-section diagram of a septic tank:

A - Wastewater in B - Scum Layer
C - Water D - Sludge Layer
E - To Drain Field  

There are three layers in your septic tank. The scum layer is made up of anything that floats. The sludge slayer is made up of anything that sinks. In between the scum and sludge layers is water free of solids. The water contains bacteria and chemicals like nitrogen and phosphorous that act as fertilizers.

The wastewater from your home goes down your drains and comes into the septic tank from sewer pipes:

A - Toilet B - Sink
C - Bathtub D - Vent Stack
E - To Septic Tank  

A septic tank naturally produces gases (caused by bacteria breaking down the organic material in the wastewater), and these gases don't smell good. Sinks therefore have loops of pipe called P-traps that hold water in the lower loop and block the gases from flowing back into the house. The gases flow up a vent pipe instead -- if you look at the roof of any house, you will see one or more vent pipes poking through.

As new water enters the tank, it displaces the water that's already there. This water flows out of the septic tank and into a drain field. A drain field is made of perforated pipes buried in trenches filled with gravel. The following diagram shows an overhead view of a house, septic tank, distribution box and drain field:

A drain field pipe is 4 inches in diameter and perforated and is buried in a trench that is a maximum of 3 feet deep and is 3 feet wide. Gravel fills the bottom of the trench and dirt covers the gravel.

Water is absorbed and filtered by the soil in the drain field. Drain field size is determined by how well the ground absorbs water. If the ground is hard clay that absorbs water slowly, the drain field has to be much larger.
A septic system is normally powered by gravity. Water flows down from the house to the tank, and down from the tank to the drain field. It is a completely passive system.