Why does my toilet keep clogging?
Think about it in two groups. The first group is the toilet itself: what you flush, and how well it flushes. The second group is the pipe behind it. A toilet that clogs only now and then, and clears with a plunger, is often in the first group. A toilet that clogs every few days, or only after something else in the house runs, is more likely in the second.
Is it what goes down the toilet?
Start with the simplest. Toilet paper is made to fall apart in water. Little else is.
- Wipes labeled flushable. They hold together far longer than paper. They snag at the bend in the trap, and everything behind them catches.
- Too much paper at once. A big wad can overload even a healthy flush.
- Cotton swabs, floss, dental picks and hair. Floss and hair wrap around rough spots in the pipe and make a net.
- Feminine products, diapers, paper towels and tissues. None of these are designed to break down in a drain.
- Small objects. Toys, bottle caps and brushes find their way into toilets and rest in the trap.
If the clog was a one-time event that cleared with a plunger, this is the likely cause.
Why does my toilet clog every time I poop?
When it only happens with a bowel movement, the load is usually more than the flush can carry, and the flush may be weaker than it should be. Add a lot of paper to that and the trap fills before the siphon can pull it through. Check the tank water level and the rim holes in the next section, flush twice for a large load instead of once, and use less paper per flush. If it happens even with a small load and little paper, a partial blockage in the trap or line is likely, and the sections after the next one apply.
Is the flush too weak?
A toilet clears itself with a rush of water that siphons the trap clean. If the siphon is weak, solids and paper only get part of the way.
1. Check the tank water level. Lift the lid. Many tanks have a waterline mark molded or printed inside, and the toilet maker's guide says to adjust the water level to match it. If yours has no mark, fill valve instructions commonly put the level a little below the top of the overflow tube, around half an inch. A low tank means less water per flush. Adjust the fill valve or float to raise it.
2. Check the rim jets. Under the lip of the bowl are small holes that feed the swirl. Mineral from hard water can build up inside them, and the USGS lists hardness among the common problems in mineralized groundwater in northern Ada County. Hold a mirror under the rim. Blocked holes can be scraped with a stiff wire or an unfolded paper clip, and the passages can be soaked in white vinegar afterward, which dissolves mineral scale.
3. Check the siphon jet. This is the larger hole near the bottom of the bowl. Scale there weakens the flush too.
4. Consider the age of the toilet. The EPA says the former low-flow toilets of the 1990s were sometimes associated with performance issues, such as requiring double flushing. If yours is from that era, replacing the toilet may be the long-term answer, and our toilet, faucet and sink repair page covers that side of the work.
Why is my toilet clogged with nothing in it?
A bowl that fills and sinks slowly even when almost nothing went down is not being overloaded by what you flushed. The usual causes are a trap with a film of paper, hair and mineral on its walls, a weak flush from low tank water or blocked rim holes, a vent that is not letting air in, or a narrowing somewhere behind the toilet. Look at the flush first, because it costs nothing. If the tank and rim holes are fine, treat it as a partial blockage.
Is there a partial blockage in the trap or the line?
This is the cause people miss. A trap with a stubborn film of paper, hair and mineral on its walls can look clear and still catch things. A branch line with a small restriction behind the toilet can do the same. The signs:
- The toilet drains, but slowly.
- The water rises, then sinks over a few minutes.
- It clogs with only normal use.
- A plunger clears it every time, and every time it comes back.
A closet auger helps with a trap that has built up. Our guide to how to unclog a toilet shows the steps. If the auger clears a good amount of material and the toilet works for a while, the trap was the issue.
Why does my toilet keep clogging after snaking?
An auger clears the trap and the first stretch of pipe beyond it. If the toilet clogs again within days, the restriction that is catching paper is farther along than a closet auger reaches, or the line has a problem such as roots, a low spot or scale that rebuilds the blockage. An auger that passes through easily and a toilet that still clogs puts the trouble past the toilet.
Could a blocked vent make my toilet keep clogging?
Every drain line needs air. The vent pipe through the roof lets air in behind the water as it leaves, and without air the flush can slow, gurgle, or leave water in the bowl. A vent can clog with leaves or debris, a bird or small animal nest, or frost and ice in cold weather, which the North Dakota State University Extension notes can form a layer thick enough to close off the end of the stack.
Signs of a blocked vent: gurgling from the toilet or other drains when something runs, a slow-draining bowl that comes and goes, and sewer smell in the house. A vent opens on the roof, so this one is not a casual homeowner job. Roof work carries a real fall risk, and an icy roof is the worst case.
Could it be the main line or the septic tank?
Several things in the pipe past the toilet cause repeat clogs. Tree roots can enter a joint and catch paper. A section of pipe can settle into a low spot that holds water. Old iron pipe can narrow inside from scale. If a house is on septic, a tank that is full or an outlet that is blocked backs up into the lowest fixture first, often a ground-floor toilet.
How this shows up:
- More than one fixture is slow, or the tub gurgles when you flush. That means the problem is shared between fixtures, in the drain line or its vent.
- The toilet acts up when the washing machine drains.
- Water or sewage rises in a tub or shower. Stop using water and call.
- The house is on septic and it has been a while since the tank was pumped. See signs your septic tank is full.
How do I stop my toilet from clogging?
- Flush only toilet paper and waste. Put wipes, floss, swabs and hair in the trash.
- Use less paper per flush and flush twice for a heavy load.
- Check the tank water level and the rim holes once a year.
- Fix a slow bowl early. A toilet that drains slowly for months is a pipe that is closing.
- If you rent, tell the property manager in writing the first time it happens, and again if it returns.
Where this goes wrong
- Plunging the same clog again and again. If you have to do it every week, plunging is treating the symptom.
- Chemical openers. Some drain opener labels say not to use the product in a toilet. Never mix products, and protect your eyes and skin if you must plunge or snake through one.
- Ignoring a slow drain. A toilet that is slow for months is telling you the pipe is closing.
- Replacing the toilet to cure a line problem. A new toilet on a restricted line will clog too.
When should I stop and call a plumber?
Call if:
- The toilet clogs again within days of clearing it.
- More than one fixture is slow, gurgles, or backs up.
- Sewage comes up in a tub, shower or floor drain.
- The auger goes in without meeting a clog and the problem continues.
- You smell sewage inside the house.
- The house is on septic and the tank has not been pumped in a long time.
See our clogged toilet page for the service, recurring drain backups for lines that keep returning, and sewer line backing up if the signs point to the main. If you are already at the plunger stage, the guide to a plunger that is not working has the order to try things in.
What it costs to have us do it
We do not publish a number for a clogged toilet, because the honest answer depends on what is wrong. What moves it: whether the clog is at the fixture or out in the line, whether the toilet has to come off the floor, whether a usable cleanout exists or has to be created, how far out the blockage sits, cable versus jetting, and city sewer versus septic. Our drain cleaning special is $59 and a 1,000-gallon septic pump-out is a flat $395. Everything else is quoted on site, in writing, after we look. Estimates are free.
How do I tell whether it is my toilet or my main line?
If more than one fixture is slow, a tub gurgles when you flush, or the washing machine sets the toilet off, suspect the line.
Can a full septic tank clog a toilet?
Yes. A full tank backs up into the lowest fixture first, often a ground-floor toilet.
Why does my toilet keep clogging in an apartment or rental?
The causes are the same, but the repair is the landlord's call. Report it in writing the first time, and report it again if it returns within days, since that suggests the line and not the fixture.
What do I do when a toilet keeps clogging with no clear cause?
Check the tank water level, look under the rim for blocked holes, and cut back on paper and wipes. If it still clogs within days, the cause is past the toilet and needs a look.
Where we work
American Rooter & Drain was established in Caldwell, Idaho in 1945 and has worked the greater Treasure Valley since 1945. We clear toilets and drains in Boise, Nampa, Caldwell, Meridian, Kuna, Eagle, Star, Middleton, Garden City, Emmett and the rest of the valley, plus Ontario, Nyssa and Vale in Oregon. See what we do in Boise, Nampa, Caldwell and Meridian. Call (208) 366-5771, days, nights, weekends and holidays.
