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Toilets and drains

What is okay to flush or pour down the drain?

As discussed on Flood Facts and Tips, sewage backups can occur for a number of reasons. There are many ways a homeowner can reduce their risk. One very important way is to know what is and isn’t acceptable to flush down a toilet or pour down a drain.

Here are some things that definitely should not go into the sewer system!

Fats, oils, and grease

Any and all cooking oils, grease, fats and other similar products should not be poured down the drain! While they may be liquid while being poured, they will very soon cool down and solidify, and this usually happens somewhere within your own plumbing, or your own sewer lateral. While it may make sense that flushing it down with hot water will help, it doesn’t – it might just make it a bit further down the drain before it solidifies and plugs up your own plumbing, or the municipal sewer system.

Pour cooled cooking grease, fat, or lard into a paper cup. Let the material solidify and then place in your Green Bin. Small amounts of cooking or vegetable oils, should be poured into a small plastic screw-top bottle. Seal the lid tightly and place in your garbage.

Feminine hygiene products

Feminine hygiene products generally do not breakdown quickly and tend to plug up pipes and cause problems for sewage pumps located within the municipal sewage collection system. Even if the packaging claims they are biodegradable, that doesn’t mean they are suitable for toilet flushing!

Disposal should be in the garbage, even if the packaging suggests otherwise.

Reduce single-use plastics with Sustainable Kingston!

Flushing plastics and other garbage creates health, safety and environmental risks when equipment fails. Sustainable Kingston hosts an annual Plastic-Free Summer Challenge to reduce or eliminate single-use plastics, such as tampon applicators and plastic dental floss. Check it out here

Sustainable Kingston logo

Paper products

The only paper product suitable for flushing is toilet paper.

Other paper products, like facial tissues, paper towel, newspaper, cardboard, and wipes of any kind are simply not suitable for flushing. When items like these are flushed, they don’t break down quickly, and can cause buildups of material and blockages that may cause a sewage backup.

Some paper products belong in your recycling grey box (like newspapers and clean cardboard), some should go into your Green Bin (such as parchment paper and soiled pizza boxes), while other items belong in the garbage (wipes of every kind).

do not flush wipes of any kind


There are many different kinds of wipes available today, including baby wipes, feminine hygiene wipes, and antibacterial wipes. Generally, these do not degrade quickly and will cause blockages in the sewer system. Many of them have packaging that claims they are biodegradable, or even flushable, but they are not. (For example, see this CTV news story on wipes).

Wipes are better off in the garbage.


Large masses of hair from haircuts or cutting a pet’s fur often stay clumped together and do not break apart into loose materials quickly. Large masses of hair are sometimes found in lift station pumps and stuck in sewer mains.

Hair should be swept up and placed in the Green Bin for composting.

Dental floss

While it might seem insignificant, dental floss in the sewer system creates a risk, mainly at municipal pump stations. It is usually a fairly tough and tear-resistant product that gets caught up in pump impellers.

Used dental floss should be disposed of in the garbage.

Disposable diapers and cloth diaper liners

Diapers are large enough that they can’t be flushed. Lo and behold, they have been found lodged in sanitary laterals as the cause for a home’s sewage backup. They are simply too big for the sewer.

Disposable diapers and cloth diaper liners are not flushable and need to go in the garbage. This applies to all types of diapers and cloth diaper liners, biodegradable or not. 

Food scraps and “garburators”

Food grinders in sinks are illegal in Kingston.  See City of Kingston By-law No. 2008-192 (“The Sewer By-law”).

Why? Food scraps and grinds that make their way into the sanitary sewer put additional stress on the treatment process and also add solids to the sanitary sewage stream that compromise the flow in the sewers.

There is a better place and use for food scraps: the Green Bin. The City of Kingston Green Bin program accepts all your food scraps or compostable items you don’t want to use for your own composter. This is the best avenue for all your food scraps.


Pharmaceuticals are a very big problem in that sewage treatment systems are not designed to deal with the myriad of chemicals that are in them.

These items can be brought to local pharmacies for disposal. Visit the Ontario Medications Return Program website.


Some people mistakenly dispose of hypodermic needles into the sewer system.

Since all hypodermic needles are classified as biohazard risks, their presence in the wastewater collection system presents special problems and dangers for wastewater collection and for wastewater treatment employees.

Never flush needles down the toilet.

All hypodermic needles should be treated as Household Hazardous Waste and that includes having special disposal instructions. Refer to the City of Kingston’s Waste Sorting Look-up tool for advice.


The treatment process is designed specifically to treat domestic sewage and human waste. It is not designed to treat the huge variety of chemicals that are present in other day-to-day products.

You should never dispose of the following materials down a drain or your toilet:

  • Oils, greases, anti-freezes and fuels from cars, lawnmowers, bikes, etc.
  • Pesticides and herbicides
  • Paints and paint thinners, solvents, turpentine and nail polish remover
  • Cleaning products
  • Flammable or corrosive products

 See the Hazardous Waste section in Recycling/Special Diversion at the City of Kingston’s web site.

Pet waste

The treatment process is not designed to handle some of the unique pathogens that may accompany pet waste.

Pet waste should be disposed of in the garbage. This includes kitty litter - even kitty litter marked 'flushable'!

What about storm sewers?

Your street’s storm sewers are never the right place to dispose of any of the above things either.

Any waste that’s not appropriate for the sanitary sewer is not safe for the storm sewer. The storm sewer is for storm water runoff only. Everything else should be being disposed of elsewhere.

Responsible waste disposal

When disposing of household waste, please recycle what you can and dispose of the rest in a responsible manner. Use common sense to help protect the environment, as well as our sanitary sewers, storm sewers, water treatment facilities, and our operators.

When in doubt about waste disposal, use the City of Kingston’s terrific online resource: Waste Sorting Look-up.

Additional information