Toilets are the most under-appreciated fixture in your house — until one clogs. Toilet clogging happens for two very different reasons: something got flushed that shouldn’t have, or there’s a structural issue in the toilet itself, the vent, or the line beyond it. Below, the plumbers at The 5 Star Plumbing break down the ten most common items that clog toilets, the less obvious structural causes, and what you can safely try before calling for help.
A Note on Low-Flow Toilets
Low-flow toilets are a great way to keep water bills down, but we frequently see them contributing to clogging issues, especially on older units. Toilets manufactured between 1994 and 1997 — often called first-generation low-flow toilets — use too little water pressure to fully clear waste from the drain line. If your toilet is from that era and clogs often, the toilet itself, not your habits, may be the real problem.
10 Common Household Items That Clog Toilets
1. Bathroom Wipes
Bathroom wipes have become a popular alternative to toilet paper, but even wipes labeled “flushable” can still cause clogs. The EPA has documented that these wipes don’t break down the way toilet paper does, even after they successfully flush. Solution: throw wipes — bathroom, baby, or face — in the trash instead.
2. Hair
Hair is natural, but that doesn’t make it safe to flush. It clumps together in pipes and forms blockages over time, the same way it does in a shower or sink drain. Solution: throw loose hair in the trash rather than flushing it.
3. Fats, Oils, and Grease
Fats, oils, and grease flush as liquids, but they cool and harden inside your pipes, building up into blockages over time. Solution: pour FOG into a disposable container and throw it in the trash once it’s full.
4. Disposable Diapers
Diapers are made of absorbent plastic material designed to expand when wet — exactly what you don’t want inside a pipe. Solution: dispose of diapers in the trash. If one does go down, shut off the water to the toilet and call a plumber.
5. Prescription Medication
Flushing medication seems convenient, but it dissolves into wastewater and can contaminate groundwater and harm wildlife downstream. The FDA recommends using a take-back program or your pharmacy’s disposal guidance instead. Solution: ask your doctor or pharmacist for the correct disposal method for your specific medication.
6. Condoms
Condoms seem small enough to flush safely, but the latex doesn’t break down and can cause real problems for septic systems and treatment plants. Solution: wrap discreetly in toilet paper and dispose of in the trash.
7. Cotton Balls and Swabs
Cotton doesn’t break down when flushed. Instead, it absorbs water and can get lodged in pipe bends, creating significant blockages. Solution: throw cotton balls and swabs in the trash after use.
8. Paper Towels
Paper towels are built to absorb spills, not to break down in water the way toilet paper does. Flushing them is one of the fastest ways to create a clog. Solution: throw used paper towels in the trash, and call a plumber if one is already stuck.
9. Dental Floss
Dental floss isn’t biodegradable, and it tangles around other debris in your pipes, making clogs larger and harder to clear. Solution: throw used floss in the trash immediately after flossing.
10. Cigarette Butts
Cigarette butts contain chemicals that can end up in the water supply, and like floss, they don’t biodegrade. Solution: dispose of cigarette butts in a proper receptacle, never the toilet.
Toilet Clogs Caused by More Than What You Flush
Not every clog comes from something that went down the drain. A few structural issues cause recurring clogs even when you’re careful about what you flush:
A Blocked Toilet Trap
The S-shaped section between the bowl and the drain, known as the trap, is designed to catch objects before they travel further into your plumbing. Non-flushable items that make it this far often get stuck here first — an auger can usually clear it.
A Blocked Vent Pipe
Every home’s toilet connects to a vent that runs to the roof, letting air into the system to keep flushes at full pressure. A blocked vent quietly reduces flushing power and causes clogs that have nothing to do with what’s been flushed. Checking it means climbing to the roof and clearing any debris from the vent opening — if that’s not something you’re comfortable doing yourself, a plumber can check and clear it safely.
A Clog in the Sewer Line
When an item makes it past the trap and the drain without stopping, it can end up lodged in the sewer line itself — the worst-case version of a toilet clog, since it can affect every fixture in the house rather than just one toilet. This almost always requires professional diagnosis and repair.
How to Unclog a Toilet Yourself
For a straightforward clog, a few DIY methods are worth trying before calling for help:
- Plunger and dish soap — pour about half a cup of dish soap into the bowl to act as a lubricant, wait a few minutes, then plunge.
- Hot water — if soap alone doesn’t work, add hot water from waist height; the force can help dislodge the blockage.
- A straightened wire hanger — if you don’t have a plunger handy, a straightened wire hanger can serve as a makeshift drain snake for a solid blockage.
- Baking soda and vinegar — one cup of baking soda with two cups of vinegar, left to fizz for about half an hour, can loosen milder clogs naturally.
If none of these clear it, or the clog keeps coming back, that’s a sign of one of the structural causes above rather than something you flushed — time to call a professional rather than keep trying DIY fixes.
Prevent Toilet Clogs Going Forward
The only things that should go down a toilet are human waste and toilet paper — everything else risks a clog sooner or later. If one of the items above does end up flushed, or you’re dealing with a stubborn clog that won’t clear, The 5 Star Plumbing is ready to help.
Frequently Asked Questions
Why does my toilet clog even though I only flush toilet paper?
A low-flow toilet, a partially blocked vent, or early sediment buildup in the trap can all cause recurring clogs even with normal use. If it keeps happening, it’s worth having a plumber check for one of these structural causes.
Is it safe to use a chemical drain cleaner in a toilet?
We don’t recommend it. Chemical cleaners are harsh on older pipes and porcelain, and they’re generally ineffective against solid blockages like wipes or foreign objects. A plunger, auger, or professional visit is safer and more effective.
How do I know if my toilet clog is actually a sewer line problem?
If more than one drain in the house is backing up at the same time — not just the toilet — that’s a strong sign the issue is in the sewer line rather than the toilet itself, and it needs a professional inspection.
