Think of your system in four parts.

1. Fixtures (sinks, tub, showers, toilets, washing machine,
dish washer)
2. Inlet line or main line
3. Tank (usually 1000 gallons)
4. Field lines (125’ per bedroom minimum)

First let’s ask a few questions.

Did the backup occur very suddenly, or have you been experiencing sluggish drains, or “gurgling” for sometime? These are not hard fast rules but generally speaking, a sudden backup is going to be a blocked inlet line. You may have had some warning, but once it backed up you are very limited to the amount of water you could use in short periods of time. Inlet lines can become completely blocked. Some type of drain cleaning will probably be necessary.

Field line problems tend to be more forgiving. Many times you can continue to use the system with a reduced flow. Field lines rarely become completely blocked and water will keep passing through albeit slower than what you normally use. This is particularly true with the amounts of water the clothes washer and shower use. On sloping lots full-blown field line problems may not cause any backup at all. The water may erupt in the yard as fast as it is being used in the house.

Many people do not realize that a septic tank stays “full” all the time. A tank pumped on Monday is probably “full” by Friday. As you can see in the illustration a “full tank” is below the inlet, and approximately 8-12” below the lid. If high water usage causes sluggish drains or even backups more than likely there is a field line problem. The field lines are supposed to take water as fast as it is used. It is possible to saturate a system, which it can recover from with time. However, repeated problems with water usage, indicates that there is a blockage between the tank and the field lines or the field lines are working at minimal absorption.

When the field lines fail, the water level in the tank can remain higher than normal. If this level reaches the inlet, the inlet can remain full and cause sluggishness or back-ups. At this point you are using water faster than the field lines can take it. This water may fluctuate several inches in the tank but if the inlet stays full for long periods of time it may build up a blockage and need to be snaked out.

Now back to our question. “My toilet is backing up do I need to have my tank cleaned?” The tank is rarely the problem. If you have a blocked inlet line pumping the tank will not help at all. It will however confirm where the problem is, the inlet line or the field lines.

If your tank is flooded, pumping will give you immediate relief. This will last at least as long as it takes you to refill the tank (3 to 7 days). It can last even longer since the field lines have had some time to dry. Daily flow is estimated at 75 gallons per person.

Cleaning the tank is maintenance, it is one of the most important things a homeowner can do to insure the life of their onsite system.

• Do it as needed
• Do it to help identify a problem
• Do it for relief