Spring is in the air. Hopefully in your yard, the fragrance of lilacs is not overwhelmed by the aroma of a failing septic system. Other signs of a septic system problem include a toilet or sink backing up when you flush or do laundry, sewage ponding on the surface of your yard or even backing up into your home (hard to miss), or patches of lush green grass atop your leaching field.
The U.S. EPA estimates that, nationwide, at least one out of every 10 septic systems is failing. This can threaten your family and neighbors' health, reduce the value of your property, and cost a lot of money to fix. It can also contaminate drinking water, lakes, and streams with nutrients like nitrates or phosphorus, chemicals and chlorides, and pathogens like bacteria or viruses.
Here’s how a septic system is supposed to work. Wastewater goes down the drain into a tank, where the solids are digested or settle out. The liquid overflows through a distribution box into a drainfield, also called a leaching field. Submerged baffles keep floating scum from being discharged. The water trickling out of the leaching system is eventually purified by biological, physical and chemical processes, and returns to recharge the groundwater.
A conventional septic system should last about 30 years. Here are some things that can cause the system to go bad.
- Neglecting to regularly inspect and clean the septic tank. If sludge or scum is allowed to escape into the distribution box and from there into the leaching field, the soil will quickly become clogged. If this happens, the liquid will no longer be able to percolate into the soil. Broken baffles in the septic tank can cause this condition. Failure to have the tank pumped regularly (e.g., every 3-5 years) can also lead to a situation where the sludge and scum overwhelm the baffles.
- Improper use of the system. A leaching field is not designed to handle solids. If solids do overflow from the tank into the leaching system, they will clog the holes. If toxic chemicals like solvents and pesticides are poured down the drain, they can destroy the bacteria that break down solids in the septic tank, and pollute groundwater. Using recommended quantities of laundry soap, detergents, bleaches, toilet bowl cleaners and caustic drain cleaners should not adversely affect the system.
- Poor soil conditions and/or faulty design or installation. A leaching system placed in unsuitable soil, a system that is too small for the house it serves, or an improperly constructed system can all lead to early failure. Driving heavy machinery over it can compact the soil or damage the system.
- High Water Table. During really wet weather, groundwater may rise into the leaching field and force sewage upward to the ground surface. This may mean the system needs to be re-installed at a higher level. It may also be possible to intercept the high groundwater with a series of “curtain drains” around the system. Leaking fixtures or overuse of water can also overtax the system. One leaky toilet can add as much as 200 extra gallons of water per day to your tank.
Just because your septic system is out of sight does not mean it should be out of mind. Most problems can be prevented by having it inspected and the tank pumped regularly by a licensed inspector/contractor. (One of whom has the motto “We’re #1 in the #2 business.”) A regular cleaning costs about $130 to $200. For more information on how to avoid problems with your septic system, see www.woodstockconservation.org/septic.htm.