Septic System Repair

Uh-oh! Smells like trouble with the septic system! This Fix-It Guide on septic system repair tells how a septic system works, what often goes wrong and how to identify the septic system problem. It then directs you to instructions for clearing a main drain.

How Does a Septic System Work?

Septic System Repair

Components of a typical septic system.

A septic system transfers liquid and solid household wastes to a holding tank for treatment. A house’s sewer line delivers the waste to a septic tank buried nearby. Solid wastes settle to the bottom of the tank where microorganisms digest it. Waste water flows to distribution boxes that release it through drain pipes for dispersal in the drain field. The septic tank should be pumped of accumulated solids as needed. Some plumbing codes require that water from sinks and showers (called grey water) is distributed in a separate system that doesn’t require a chemically active tank.

How often should you have your septic tank pumped? It depends on the capacity of the tank and the number of people who live in the house. A household of two with a 1,000-gallon tank may need to have the tank pumped only about every six years. But a household of six with a tank of 2,000 gallons may need to have it pumped about every three years. You can call a septic pumping service for additional guidelines; some will come check the level of your tank once a year and advise you.

What Can Go Wrong with a Septic System?

The main drain from the house to the septic system may become clogged. Pipes in the drain field may be broken. The septic tank may overflow. In many cases, the problem is caused by damage to the surrounding soil (heavy equipment) or the lack of periodic pumping.


If your home is on a septic system, don’t dispose of any chemicals that may kill the bacteria, such as paint thinner or photographic chemicals, by putting them down the drain. Also avoid flushing anything that won’t dissolve in water. At the least it won’t dissolve and you’ll have to have it pumped out. At worst, it will clog the system and cause bigger problems. And make sure that your garbage disposer is rated for use with septic tanks; the owner’s manual will tell you.

How Can I Identify a Septic System Problem?

  • If all the drains in the house work sluggishly or don’t drain at all, check and clear the main drain.
  • If you smell sewage around the septic tank or the drain field, or if you see black or gray water oozing up from the drain field, call for professional septic system service.

Fix-It Tip

When you purchase a home with a septic system, make sure you get a plot map that shows the location of the septic tank and drain field. In the future, don’t plant any trees or large shrubs near the septic tank or on top of the field because roots can interfere with the tank and pipes.