(Image provided by Cornell Cooperative Extension Publication FS-1)

Septic systems are used to treat and dispose of wastewater. When properly used and maintained, they safeguard human, animal, and plant health by breaking down wastewater and removing potential contaminants. It’s a two-step process.

The septic tank allow solids in the wastewater to separate from the liquid. Heaver solids settle to the bottom, forming a sludge layer. Lighter solids (e.g. grease, hair) float to the surface, forming a scum layer. Although some of the solids are broken down by bacteria, most remain in the tank until the tank is pumped out. Inlet and outlet baffles enhance storage and treatment.

The liquid waste, called effluent, flows out of the tank into a distribution box, and through a soil absorption or ‘leach’ field. A typical leach field consists of a series of perforated pipes buried in gravel-filled trenches. As effluent seeps through the trenches, it’s filtered by soil particles and broken down by soil bacteria. A failing or malfunctioning septic system can allow disease-causing organisms and other pollutants into the environment.

Unless the sludge and floating scum are periodically pumped from the tank, even a properly designed septic system can fail. But, for most homeowners, checking sludge and scum build-up is too objectionable a task. They choose, instead, to simply have the tank pumped out, cleaned, and inspected by a professional at 3- to 5-year intervals, depending upon the size of the tank, the number of people using the system, and the amount and quality of solids entering the tank.

It’s sometimes surprising to see what some people put into their septic systems: fats, grease, coffee grounds, cigarette butts, sanitary napkins, cat litter, just to name a few. All of these will, most certainly, clog a septic system.

Even heavy paper items, such as paper towels, should be avoided. Believe it or not, accumulations of facial tissue can cause problems. The safest and best approach is to use only easily decomposed, one-ply toilet tissue.

You can further reduce or minimize the amount of solids put into the system by avoiding the use or installation of garbage disposal units. Almost all of the food waste put into garbage disposals can be composted anyway.

Then there are the yeasts, enzymes, bacteria, and chemicals that are sold with claims that they improve septic system performance. These additives are not an alternative to proper maintenance, and do not eliminate the need for routine pumping of septic tanks. In fact, there’s no scientific evidence to support claims that any of these additives are effective. And some of them can actually suspend; clogging drainage lines and leach fields when they do.

Claims that commercial biological additives are needed to begin decomposition after pumping are not supported by science, either. The sludge residue that’s left behind contains more than enough active microorganisms to restart the decomposition process.

Try to limit and reduce the volume of wastewater put into your septic system. Repair or replace leaky fixtures and, if at all possible, install low-flow toilets and inexpensive faucet and showerhead aerators. Wash only full loads of dishes and laundry. And spread your clothes and dishwashing out over time, instead of washing several loads at once. Not only will these practices prolong the life and improve the performance of your septic system, they’ll reduce hot water consumption, conserving energy and saving you money.

Sensible use of detergents, soaps, bleaches, disinfectants, etc. will not harm your septic system. Excessive use will. And it’s extremely important to recognize that in areas where there’s a high density of septic systems, there’s an increased impact on groundwater from the disposal of household cleaners.

It’s important that you know the location of your septic system. Finding this out may require going into the basement, cellar, or crawl space to find where and in what direction the sewer pipe goes out through the wall. You can then check that area of the yard for a spot where the grass either doesn’t grow or grows quite well. This will most likely also be an area that is either slightly depressed or slightly mounded over. When a likely site is found, probing it with a thin metal rod will help to determine if, indeed, the tank is there. Once the tank is found, its location can be marked with a stake, statue, etc. Or consider drawing a map showing the house, septic tank, and leach field.

Never plant trees over leech fields and prevent tree roots from growing into them. Don’t pave, build, or drive heavy vehicles over them. And always divert gutters, drains, and other sources of water runoff away from them.