And now, a few words on a topic that might have slipped your mind: your septic system.
Despite the temptation to treat your septic system as “out of sight, out of mind,” you need to pay occasional attention to make sure your system is functioning properly, both for your own health and safety and for the sake of the water quality of everyone (and everything) living downstream.
The workings of a septic system are no big mystery: in general, a system consists of only two components. Directly connected to the house is the septic tank, essentially a storage box holding upwards of a thousand gallons of effluent. The function of the tank is to allow wastes to separate into three layers. Substances heavier than water sink to the bottom and become “sludge.” Above that is a watery middle layer, laden with dissolved waste substances, such as phosphates and nitrogen-rich urea. Topping it off are the substances lighter than water, such as oils and fats, which float as a scum layer.
Each time we flush, shower, or otherwise run water down the drain, the incoming waste stratifies into these three layers in the septic tank. The incoming waste also causes some of the liquidy middle layer to be forced from the tank, where a pipe drains it out to the septic system’s second component, the leachfield.
The leachfield is a series of perforated pipes buried not too far below the ground’s surface, in a soil of high porosity. The leachfield’s function is to distribute the liquid from the tank over a large area, allowing the soil to filter and cleanse the liquid and the soil microbes to complete the breakdown of wastes.
This is only possible, however, if the septic tank is cleaned regularly. If not, the sludge layer fills the bottom of the tank and starts to ooze out through the middle layer’s exit pipe, with bad consequences for the leachfield downstream.
When the sludge hits the leachfield, it blocks up the tiny soil pores that are intended only to filter water. (This can also happen in a house where excessive grease is flushed down the drain, causing the grease layer in the septic tank to grow thick enough to reach the middle layer exit pipe.) Either way, sewage will back up into the house.
The crucial piece of septic system maintenance, therefore, is pumping out the septic tank regularly. For most households, every three years will be sufficient. Households with many residents should consider a two-year schedule, while seasonal dwellings might get by for four or five years between cleanings. Ask your local tank pumper for advice the next time he or she is in the neighborhood.
It follows that practices that increase solids in the tank should be avoided. Don’t install a garbage grinder in the kitchen sink, as this will double the amount of solid waste reaching the tank. Cloth, plastics, diapers, feminine hygiene products, and cigarette butts simply don’t belong in a septic system. Neither do toxic chemicals such as herbicides, pesticides, disinfectants, paint thinner, solvents, and oils. Bacteria lack the means to break these substances down, so these toxins will eventually percolate into the groundwater.
Surprisingly, washing machines are one of the chief causes of leachfield failure. The vigorous cleaning generates lint: tiny fibers that don’t settle out of the water but instead make their way into the pores of the soil and clog them irreversibly. This problem is bigger than it seems since an average family’s clothes produce enough lint in a year to carpet the living room. And nowadays, much of that lint is non-biodegradeable polyester and nylon.
Crude washing machine filters, such as lint screens, allow 95 percent of the fibers to pass through; however, special, reuseable filters that effectively remove lint and fit to the washing machine outlet hose are now available. Multiple, back-to-back laundry loads can overwhelm septic systems with the sheer volume of water, preventing sludge from settling and sending it to the leachfield instead. Spreading laundry loads over several days also helps avoid septic overloading.
Above ground, the crucial maintenance is to let the leachfield do its job. Refrain from driving or parking on the field, since compaction makes the soil non-porous. In fact, it is best not to disturb the leachfield at all, apart from planting grass on it and keeping it mowed. Trees and shrubs with their big, clogging roots should not be allowed nearby. Finally, divert rain runoff from nearby roofs or driveways, lest it take up the leachfield’s precious filtering capacity.
Management of a septic system is an easy but often-overlooked task. A few hours and a few hundred dollars in maintenance per year can avoid tens of thousands of dollars in costs to clean up and repair a failed system, along with significant health risks and environmental damage.