After putting it off for years, I finally got our septic tank pumped out.

It felt a bit like it does when you reach an age when it might be a good idea to undergo some mildly invasive medical test. After all, it’s a relatively painless exercise that will either provide reassurance or spur you to some form of self-preservative action.

I’d decided not to tempt fate any longer.

I set to work with a shovel, occasionally using a length of steel rebar for exploratory probing, and before long, I located the concrete tank. Exposing the access hatch, however, required a great deal of digging.

The local septic guy I chose at random from the phone book came in his pumper truck and lowered a fat hose into the opening. He emptied the contents, amid a suitably impolite slurping noise. To my great relief, he said the system appeared to be functioning as it should.

In addition to providing peace of mind for a few years, this modest investment set us up well for regular pump-outs in the future.

Knowing the tank’s location was a good start, but since it was buried so deep we also took the opportunity to fit it with a riser—essentially a concrete cylinder a couple feet in diameter that is installed upright on the access opening, topped with its own tight-fitting hatch that comes close to the grade of the lawn. This means very little excavation will be required the next time the tank needs attention.

And when will that be? Regulatory bodies generally recommend an assessment every three years, and a pump-out every three to five years. They also warn that this is not a job for the do-it-yourselfer. You can do the digging, but resist the temptation—if you’re that kind of person—to open the hatch and stick your head in there for a look. The gases accumulated in the tank can kill you before you have a chance to remark on the olfactory effects.

Septic basics

To understand the importance of the pump-out, it helps to have a basic idea of how a septic system works. For roughly a quarter of Canadian homes—and closer to half in the Atlantic provinces—the absence of municipal services makes on-site sewage treatment a necessity. The first stage of these systems is the septic tank. Tanks were once made with wood, which rotted in short order, and for a time the preferred material was steel, which would eventually deteriorate due to rust. Today they’re made of concrete, fibreglass, or polyethylene.

Everything that gets flushed down the toilet or poured down the drain empties into the septic tank, where organic matter is broken down by natural bacterial action. Heavier solids settle to the bottom, and this accumulation is known as sludge. Lighter material, such as fats, form a layer on the surface that is called scum. (Yes, this is the correct technical term.)

The leaching bed

Through the separation process the wastewater is clarified, then it flows out of the tank through an opening at the far end. An underground drain pipe carries the water further away from the house to the leaching bed. Ideally this occurs by virtue of gravity, but on sites that lack natural gradient an automatic pump does the job.

The leaching bed—also known as a drain field or a tile field—comprises a series of perforated pipes buried in gravel-lined trenches, arrayed over a large area to allow the partially treated water to seep out and disperse gradually in the soil, which serves the purpose of filtration and further bacterial decomposition. Before plastic pipe was adopted, clay tiles were used, laid end to end in such a way as to allow wastewater to trickle out at the open joins. These terracotta pipes were phased out because they proved vulnerable to damage or deterioration over the years, but the term “septic tile” has stuck.

Old or new, the leaching bed in your yard should be topped with sod to prevent erosion. It’s a perfectly suitable place for a game of croquet or bocce, but it should not be covered over with pavement, patio stones, or a shed, which would prevent evaporation. Do not drive or park in this area, and keep it clear of trees or shrubs whose roots could damage the drain field.

System maintenance

The rule of thumb for septic system professionals is to pump out the tank when it’s about one third full of solids. What you want to avoid is having those solids accumulate to the point where they flow out into the leaching bed, because they will clog the pipes and back up the system—and that leaves you no choice but to excavate the yard. A device called an effluent filter can be installed at the tank outlet to prevent this from happening, but it’s not a substitute for timely pump-outs.

Regular inspections are recommended because it’s hard to estimate how full the tank is. Today there are code specifications requiring larger tanks for larger households, but in some cases extra bedrooms and bathrooms may have been added to a house without a corresponding expansion of septic capacity.

If you want to keep your septic system working well you should avoid overloading it. This sounds simplistic, but it’s your best and easiest defence against a meltdown. The amount of water that goes down the drain corresponds to the amount that flows out of the septic tank. Running a lot of water in a short period of time is particularly risky, because the flooding effect may carry solids out of the tank before they have time to settle, or the leaching bed may just become saturated, in which case it could freeze.

In addition to spreading out water use as much as possible, make sure rain runoff from your house is not being directed into the septic tank or onto the leaching field.

The same goes for backwash from a water treatment system, or water being emptied from a swimming pool or hot tub.

Safe dumping

The other main precaution has to do with what gets dumped into the septic system. If you’re a gardener, it may be helpful to think of things you would avoid putting in the compost. Does plastic garbage break down readily to create rich, healthy soil? No, it does not. What about medications, paint, and other chemical products? Definitely no. Kitty litter, cigarette filters, condoms, diapers? That just wouldn’t be right.

In fact, a septic system is actually less forgiving than a backyard composter. Kitchen waste like grease, coffee grounds and egg shells should not go down the drain. And sending organics through a garburator is not recommended unless your septic system was designed to accommodate this extra source of solids. Toilet paper is of course factored in as part of the normal waste stream, but you should not burden your system with additional fibre such as paper towels and facial tissues.

When it comes to cleaning products, use discretion. I’m kind of a zealot for vinegar and baking soda and elbow grease, but some people feel the need for a fresh scent and a fast-acting formula. Just remember, if it’s poisonous, it’ll kill some of the bacteria that are taking care of your business in the septic tank. A little bit of bleach is not going to cause your system to fail, but the watchword is moderation. There are biodegradable products available. Check the manufacturer’s label for septic-friendly credentials. Chemical drain openers are especially hard on septic systems, so it’s better to attack clogs with boiling water or a mechanical snake.

You’ve probably heard the sales pitch for septic tank additives that are supposed to boost microbial activity, to compensate for the disinfectants and detergents you send down the drain, but the provincial departments that regulate septic systems do not recommend performance-enhancing products of any kind. Naturally occurring microscopic critters will do the job just fine if you refrain from assaulting them with chemicals.

A leaching field is not meant to last forever. Eventually it will lose its absorptive capacity and you will have to dig it up and lay new pipes, but with proper use and regular pump-outs it should last 20 to 25 years or even longer. That’s lot of flushing.