Coffee Grounds & Your Septic System

Though they are always listed among the items you should never flush, coffee grounds don’t get a lot of attention—certainly not nearly as much as they should—when we talk about the proper care and maintenance of your septic system. We understand how convenient it may be to wash your old brew (grounds and all) down the drain, but read on to learn the many reasons you should never flush coffee grounds into your septic system and to discover some alternative uses for coffee grounds in and around your home.

Why You Should Never Flush Coffee Grounds into Your Septic System

There are several reasons you should never flush coffee grounds into your septic system. Some of them, you’ll probably expect, but you may be surprised by one of the most significant reasons they are on the septic system blacklist of “unflushables.”

Coffee Grounds Add to the Solids in Your Tank

In soil, coffee grounds can take as long as three months to break down. In your septic system, it takes even longer. When you consider adding grounds to the tank on a daily basis, these solids can quickly add up. As you know, adding solids to your septic tank can overwhelm the bacteria in the system allowing a build-up of solids over time. Eventually, your septic system can become overwhelmed by the solids in the tank, causing sewage to backup into your home or flow out into the drainfield, where they can cause catastrophic system failure. The only solids you should be flushing into your septic system are human waste and septic-safe toilet paper. Everything else—feminine hygiene products, “flushable” wipes, and even coffee grounds—adds to the solids in the tank. This increases how frequently you need to have your system pumped and has the potential to cause whole system failure.

Coffee Grounds Can Cause Plumbing & Septic Clogs

Anytime you put solids down the drain, you risk a plumbing clog somewhere within your pipes. But coffee grounds, in particular, are prone to clumping together and collecting in the pipe bends. Stray grounds here and there won’t create a problem in your plumbing, but a daily habit of rinsing the grounds down the drain can lead to a major clog—and headache! Once the coffee grounds make their way to your septic tank, similar clogs can build up at the intake baffle, which could allow sewage to backup into your home.

Coffee Grounds Can Upset Your System’s pH Levels

While adding to the layer of solids or causing plumbing clogs are both fairly serious problems, upsetting the pH levels of your septic tank is possibly the most significant risk you take whenever you flush coffee grounds down the drain. When used coffee grounds enter your septic tank, they effectively continue to brew. Though the brew from used grounds is much less potent, it still has the potential to throw off the chemical balance within your septic tank. The bacteria in your septic tank are responsible for breaking down solids that collect in the bottom of the tank as well as those that become suspended in the effluent. These bacteria thrive in a relatively neutral pH level between 6.5 and 7.5. Coffee is fairly acidic, with a pH level between 4.85 and 5.1. Flushing coffee grounds into your septic system not only means adding significantly to the solids in the tank, but it also means lowering your bacteria’s efficiency at breaking down solids. Anytime we interfere with the bacterial functioning of our septic system, we risk whole system failure.

Alternative Uses for Used Coffee Grounds

Alternative uses for Coffee grounds include using them as fertilizer

When the cost to replace a septic system averages between $13,000 and $25,000, the convenience of rinsing used coffee grounds down the drain just isn’t worth it. Toss them into the garbage or give some of these alternative uses a try instead.

Repel Insects Around Your Home

Because of their acidity, coffee grounds make for a pretty effective insect repellant, both in your garden and around your home. Sprinkle them around your plants in the garden to repel slugs and snails (being careful not to spread too closely to plants that do not like acidic soil). You can also scatter them near your home’s thresholds or windows to help prevent ants, stink bugs, and other creepy crawlies from venturing inside. Replenish insect-repellant coffee grounds every couple of weeks during the “high bug” months (spring, summer, early fall).

Enrich Your Compost Bin

Coffee grounds are rich in nitrogen, which is another reason they’re bad for your septic system. Added to your compost bin, used coffee grounds not only add massive levels of nitrogen to your soil, but also other minerals like magnesium, potassium, and calcium. Soil enriched with coffee grounds provides better food for your plants and also encourages worm activity, which aerates the soil and creates an ideal environment for plant growth. Adding coffee grounds to compost and soil is so beneficial and so popular that many coffee shops already offer dried coffee grounds for free to gardening enthusiasts.

Use as a Deodorizer

Because coffee has such a strong aroma, people are often surprised to learn that used coffee grounds are a fairly powerful deodorizer. But the truth is, coffee beans (and grounds) attract and absorb the smells that surround them. In fact, this is a big reason people keep their coffee beans in an airtight container. Keep a jar of dried, used coffee grounds in the back of your fridge to keep unwanted odors at bay.

Trust Supeck Septic to Set Your System Right

If you’ve made the mistake of flushing things that you shouldn’t into your septic system, the best thing to do is schedule a septic service appointment with a trust septic provider. As Northeast Ohio’s largest septic provider, Supeck Septic has made it our mission to provide exceptional routine and emergency septic care. We are an approved provider for all makes and styles of septic and aerations systems, regardless of age or complexity. Set your mind at ease and contact Supeck Septic today to schedule a service visit.

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