Septic systems and sewer systems operate differently. But there’s one golden rule when it comes to flushing: don’t flush anything other than waste and toilet paper.
The reasons behind the rule are different for each type of system.
In a septic system — which consists of a septic tank and a drainfield that typically services a single home on private property — things you flush collect in pipes and in the septic tank and can cause clogging or spillage.
For a sewer system — a municipal system that gathers and treats all the wastewater for an entire community — things you flush end up in pipes, sewer mains, or at the treatment plant, causing clogging, contamination, or worse.
Let’s take a closer look at the differences between septic and sewer systems and where things go when you flush them down.
What Happens To Things You Flush In A Septic System?
In a septic system, anything you flush just sits in your septic tank. If you make a habit of flushing non-biodegradable wipes, floss, feminine hygiene products, tissues, or other products (with the exception of toilet paper), you can end up with clogged pipes and a too-thick layer of sludge in your septic tank that can lead to stoppages or overflow. It can even keep professionals from being able to empty your system properly, leading to expensive repairs.
Do not flush:
- Disposable wipes, including “flushable” wipes
- Floss
- Paper towels
- Tissues
- Feminine hygiene products
- Hair
- Cotton balls or other swabs
You also need to be careful about harsh cleaning products and liquids such as paint and paint thinners, oils, and degreasers. These can disrupt the balance of good microbes in your system.
These kinds of products kill off the naturally occuring good microbes that break up waste and eat bad bacteria. If you use a harsh drain cleaner, it might clear the clog in your drain, but it can also cause backups or lead to spillage and groundwater pollution.
Do not use:
- Chlorine bleach
- Ammonia
- Antibacterial soaps
- Conventional drain cleaners
- Conventional toilet bowl cleaners
- Conventional oven cleaners
- Solvents, such as nail polish remover
- Bath oils
One more thing. Food scraps can clog your septic system — even something seemingly innocuous, like coffee grounds. The wastewater from your sinks, showers, washers, and tubs goes to the same place as the wastewater from your toilet: the septic tank. Don’t put anything down your sink that you wouldn’t flush. If you have a garbage disposal, avoid using it. All food waste should go into the compost or trash.
What Happens To Things You Flush In A Sewer System?
Houses on municipal sewer systems aren’t quite as prone to clogging and backups as septic systems. That said, your sewer-connected toilet is not a trash can.
Anything other than toilet paper, like floss and other nonbiodegradable products, can get stuck in pipes, causing blockages. If they make it through your pipes, they can still end up causing problems in the sewer system or at your wastewater treatment facility. According to LOTT Clean Water Alliance, a Thurston County-based organization, you should never flush anything other than human waste and toilet paper. (Here’s a visual of some of the things that have ended up in our wastewater, right in Thurston County. To see this display for yourself and learn even more, visit LOTT’s WET Science Center.)
Disposable wipes and personal hygiene and first aid products clog pipes and end up at wastewater treatment centers, where they have to be fished out. Wastewater treatment plants aren’t designed to remove compounds in medications or to treat pet waste. And things like grease, personal hygiene products, and chemical-heavy cleaners and body care products can cause problems, too. According to LOTT, these items can introduce harmful chemicals into our wastewater system and could even reach Puget Sound or groundwater aquifers.
Do not flush:
- Disposable wipes, including “flushable” wipes
- Medicines
- Pet waste
- Fats, oils, and grease
- Hygiene products
- Household products