Why Your Drains Keep Clogging (and When to Call a Plumber)

Cooking grease, oil and fat go down the drain as a liquid, then cool and stick to the pipe walls. Food scraps, coffee grounds and rice catch on that sticky layer, and over months it narrows the pipe until water barely moves.

• Wipe greasy pans with a paper towel before washing them, and put fat in the garbage or green bin once it cools.
• Scrape plates into the bin, even if you have a garbage disposal. Disposals grind food but don't make grease disappear.
• Keep coffee grounds, eggshells, pasta and rice out of the sink. They expand or settle into heavy sludge.
• Running hot water after washing dishes helps a little, but it won't remove buildup that's already there.

In showers and bathroom sinks, hair combines with soap scum and toothpaste to form stringy clumps that trap more of the same. A simple hair catcher over the drain prevents most of this. Clean the stopper and drain cover regularly.

Toilets clog for a different reason: things that shouldn't be flushed. Only human waste and toilet paper belong in a toilet. Wipes, even those labelled flushable, paper towels, cotton swabs, dental floss and feminine products don't break down the way toilet paper does. They snag in pipes and are one of the most common causes of the clogs we clear. If a toilet clogs often even when used properly, there may be a problem with the toilet itself or the drain line. Our clogged toilets and sinks service covers both.

One slow drain usually means a problem near that fixture. Several slow drains at once point further down the line, to the main drain that carries everything out of the house. Warning signs include:

• Toilets gurgling when you run a sink or the washing machine drains.
• Water coming up through the basement floor drain.
• Sewage smells in the basement.
• The lowest fixtures in the house, like a basement shower, backing up first.

In older homes, tree roots are a frequent cause. Roots are drawn to moisture and can work their way into small cracks or joints in older sewer pipes, then grow and catch waste. Other causes include pipes that have shifted or sagged, buildup over decades, or a foreign object stuck in the line.

A main line problem needs professional drain cleaning. Stop using water as much as possible until it's cleared, because everything you send down will look for the lowest way out, often the basement.

For a single slow sink or tub drain, these are worth a try:

1. Remove and clean the stopper or drain cover. You'll often find the clog right there.
2. Use a plunger. A cup plunger for sinks and tubs, a flange plunger for toilets. Block the overflow hole on a sink or tub so the pressure goes down the drain.
3. Try a small hand drain snake for hair clogs in a bathroom sink or shower.
4. Clean the P-trap under a sink. Put a bucket underneath, unscrew the trap, and clear it out. Only do this if the fittings are plastic and in good shape.

We don't recommend them. Harsh chemical cleaners often don't clear the full clog, can damage older pipes and fixtures, and create a hazard for you and for anyone who has to open the pipe afterward. If a chemical cleaner doesn't work, you're left with a sink full of caustic water. Tell your plumber if you've used one so they can take precautions.

Call a professional if:

• A drain is still slow after plunging and cleaning the stopper.
• The same drain clogs again within a few weeks.
• More than one fixture is affected, or the floor drain is backing up.
• You notice sewage smells, gurgling or water where it shouldn't be.

A plumber can clear the full length of the pipe and, if the problem keeps returning, run a camera to see what's going on inside. That's especially useful in established neighbourhoods like Rougemount, where mature trees and older sewer laterals make root intrusion more likely. If you have a finished basement and have ever had a backup, our backwater valve guide is worth a read too.

Is baking soda and vinegar safe for drains? It's gentle and won't hurt your pipes, and it can freshen a drain. It isn't strong enough to break up a real clog, though. If water is standing in the sink, a plunger or snake will do far more.

How often should drains be professionally cleaned? There's no fixed schedule for most homes. If a drain keeps slowing down, or you've had a main line backup before, regular cleaning may be worthwhile. A camera inspection can show how much buildup is in the line and help you decide.

Can tree roots be removed from a sewer line? Yes. A plumber can cut roots out and clear the line, which restores flow. Roots tend to grow back if the pipe is cracked or has open joints, so a camera inspection helps you decide whether to keep clearing it periodically or repair that section of pipe.

Is a garbage disposal bad for drains? Not if it's used properly. Run plenty of cold water while it's on, feed scraps in slowly, and keep grease, fibrous peels, bones and coffee grounds out. Even with a disposal, scraping plates into the bin is the safest habit.

Why does my drain smell? A bad smell often comes from food or hair buildup in the trap, a dry trap in a drain that's rarely used, or a venting problem. Run water in rarely used drains every so often, clean stoppers and traps, and call a plumber if the smell persists.