Why toilets clog
The trapway inside a toilet is a curved channel about two inches across. Too much paper at once, wipes, paper towels, cotton swabs, dental floss and children's toys are the usual culprits. Low-flow toilets installed decades ago used less water but sometimes struggled to clear, and older models clog more easily than modern ones. Hard water scale can also narrow the trapway and the holes under the rim over time.
When it's not the toilet
If the toilet clogs repeatedly, or water appears in the tub or shower when it flushes, the problem may be in the branch line or the main sewer line rather than the toilet. Toilets are often the first fixture to show a main line problem because they send a large volume of water at once. A plumber will test other drains before deciding where to work.
What a plumber does
- 1
Plunge properly
A flange plunger with a good seal clears many clogs that a cup plunger can't.
- 2
Use a closet auger
A short cable designed for toilets reaches through the trapway without scratching the porcelain.
- 3
Pull the toilet if needed
For objects stuck in the trapway, removing the toilet allows access from below.
- 4
Check the line
If the toilet is clear but drains are still slow, the plumber moves to the branch or main line.
Typical costs
| Job | Typical range |
|---|---|
| Toilet clog cleared with an auger | $125–$250 |
| Toilet pulled to remove an object | $200–$400 |
| Main line cleared through the toilet flange | $300–$650 |
Preventing toilet clogs
- Keep a trash can in every bathroom for wipes, swabs and hygiene products
- Teach children what can and can't go in the toilet
- Flush twice for heavy loads rather than once
- Consider replacing an old low-flow toilet that clogs often
Toilet clog: common questions
Should I keep plunging if it isn't working?+
If ten or fifteen firm plunges don't help, stop. More plunging can push a clog further or splash contaminated water.
Can I use a regular drain snake on a toilet?+
A regular snake can scratch porcelain. A closet auger is designed for toilets and is safer.
Are flushable wipes really flushable?+
They pass through the toilet but don't break down like paper, and they're a leading cause of main line clogs.
Why does my toilet clog every week?+
It may be an obstruction in the trapway, a partial clog in the line, or an older low-flow toilet. A plumber can tell which.