Septic system maintenance

Q: We just bought a home out in the country that uses a septic system rather than sewer service. The seller said that all we need to do to keep the system working well is to put an additive down the toilet once a month. Is there anything else we need to know? — Sarah and Calvin Y., Gadsden, Ala.

A: There are a few things you need to know, and a few things you need to do immediately, to make sure the septic system is really working as efficiently as the former owner claims it is.

First, a quick course on septic systems. In a home that isn’t hooked up to a municipal sewer system, liquid and solids drain from the home’s central drain waste vent into a submerged tank, located outside the house and ideally at a higher level than the ground beyond it. This tank is a very efficient primary waste processing unit.

Wastewater and solid waste “rest” in the tank, separating into three distinct tiers: solids in the bottom, liquids in the center and a crusty, funky foam at the top. Bacteria at all three levels consume and digest the waste products, dissolving them further and adding to the strata.

Meanwhile, the liquid in the middle (effluent) drains into wastewater pipes that feed into drainage lines, located down the slope in a prepared field. Layers of gravel and dirt are in place below the sod, and the effluent filters down through these layers, which purify the liquid before it reaches the water table.

Bacteria play a huge role in maintaining a “healthy” septic system, and biological additives are designed to give these bacteria extra “stuff” to munch on in a ploy to increase their productivity. However, too much of a good thing isn’t good at all, and in this case, excess additives can disturb the bacteria-to-waste balance.

Sludge can build up much faster than normal, blocking the drain pipe or seeping into the field (something the drainage lines can’t handle). In severe cases, the sludge or foam layers can block the gas vent pipes that normally keep methane gas from building up in the tank, creating a potentially explosive situation.

Rather than continuing to put additives into the system and hoping that does the trick, have a septic tank technician come out, inspect the tank and the drain field, and pump the tank if necessary. Ask him how often a biological additive should be put in — many technicians don’t recommend it at all.

Home Tip

To keep a septic system working at peak efficiency, limit use of biological additives and watch what you put down the drains. Put kitchen scraps on the compost pile and throw away grease. Don’t put chemicals of any kind down the drain — including drain cleaners, bleach and antibacterial soaps.