Toilet keeps clogging

How a toilet flush clears the bowl

A toilet doesn't push waste out with pressure from the supply line. When you press the handle, the chain lifts the flapper and the tank water drops into the bowl in a few seconds. Part of it pours out of the small holes under the rim to wash the sides. On many toilets, part shoots out of a larger hole near the bottom of the bowl, called the siphon jet. That rush fills the curved trap built into the porcelain and starts a siphon that pulls the bowl empty. The vent pipe lets air into the drain so the water can move freely.

Each part needs to do its job for a clean flush. If the tank holds less water than it should, or the flapper drops shut early, the siphon is weak and paper gets left in the trap. If the rim holes and siphon jet are crusted with minerals, the water comes in slowly instead of in a rush. If something solid is lodged in the trap, it can catch paper again and again. And if the vent or the drain line past the toilet is blocked, a stronger flush won't fix it. The trick is to find which one you have.

Why a toilet keeps clogging

Let's fix it

1. Find the pattern firstBefore fixing anything, think about when it clogs. Does it clog after big loads, or even with a little paper? Is it one toilet, or do other drains run slow too? Ask everyone in the house what goes down it. "Flushable" wipes, paper towels, tissues, cotton swabs and hygiene products are common culprits. If the clog only follows large loads, try flushing twice, once partway through. If it clogs with light use, something may be stuck in the trap (Step 5). If other drains gurgle or back up, go to Step 6 before plunging again.
   Done

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2. Fix a weak flush in the tankTurn the shutoff valve behind the toilet clockwise until it stops, then flush once to see the parts. Lift the lid and set it on a towel. With the water back on, the tank should fill to the line marked inside the tank. If there's no mark, aim for about 1 inch below the top of the overflow pipe. To raise it, turn the adjustment screw or slide the clip on the fill valve to raise the float, as its instructions show. Next, check the chain. It should have only a little slack, about 1/2 inch. Hold the handle down and watch the flapper. It should stay up until the tank is nearly empty. If it drops shut early, check for an adjustable flapper with a dial or float and set it to stay open longer, or replace a waterlogged flapper. Keep about 1/2 inch of chain slack.
   Done

   Something went wrong?

   • Now the toilet runs nonstop The chain is too tight or the water is too high. Give the chain a link of slack and lower the float slightly. See the guide for a running toilet.
   • The flapper is soft, warped or slimy A new universal flapper usually costs about $5 to $15. Match the size (2 or 3 inch) to the old one.

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3. Clean the rim jets and siphon jetFlush and watch the bowl. A healthy flush swirls fast and drops in a rush. If the water trickles down in streaks, the rim holes may be crusted. Hold a small mirror under the rim and look with a flashlight. White or brown crust around the holes means mineral buildup. Turn off the shutoff valve and flush to empty the tank. Pour about a quart of white vinegar slowly into the overflow pipe in the tank, so it runs out through the rim holes. Let it sit for an hour or more. Then poke each hole gently with a straightened paper clip, and clear the siphon jet at the bottom of the bowl the same way. Turn the water on and flush a few times.
   Done

   Something went wrong?

   • Crust won't come loose Repeat the vinegar soak overnight. Don't scrape with a screwdriver; it can chip the glaze and give new crust a place to grab. Don't mix vinegar with bleach cleaners.

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4. Plunge the clog the right wayFor the clog in front of you, use a flange plunger, the kind with a rubber sleeve that folds out of the cup. A flat sink plunger can't seal in a toilet. If the bowl is very full, turn the shutoff valve clockwise first and bail some water into a bucket. You want enough water to cover the cup. Fit the sleeve into the drain hole, then press down slowly the first time to push the air out. Pump firmly in and out about 15 to 20 times without breaking the seal, then pull up sharply. Test with a bucket of water poured into the bowl, not a flush. See how to unclog a toilet for more. If plunging hasn't helped after a few rounds, stop and use the auger in Step 5. More plunging can push a solid object deeper.
   Done

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5. Auger out a stuck objectIf the toilet clogs with light use, or a child may have dropped something in, use a closet auger. It costs about $15 to $40 and is made for toilets. The rubber or vinyl sleeve at the bend protects the porcelain. Put on gloves. Pull the cable back so only the tip shows. Set the bend in the bottom of the bowl, pointing into the drain hole. Crank clockwise while you push the cable in slowly, until the handle meets the tube. That reaches through the trap. Crank as you pull it back, since the tip often hooks what was stuck. If you feel something hard you can't hook, stop. Don't force it, since a cracked trap means a new toilet. A plumber can pull the toilet and push the object out from below.
   Done

   Something went wrong?

   • The auger stops at the same spot Try turning the crank the other way to free the tip, then go again at a slightly different angle. If it still won't pass, it's likely a solid object; call a plumber.

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6. Check the vent and main lineRun the bathroom sink and the tub for a minute while you watch the toilet. If the bowl bubbles, bobs or gurgles, the vent pipe may be blocked, or the drain past the toilet is partly clogged. See the guide for a gurgling toilet. Vents exit on the roof, so leave that work to a plumber rather than going up on a ladder. Now flush and watch the lowest drains in the house, like a tub or a basement floor drain. If water backs up there, or several drains are slow at once, the main sewer line is likely clogged. Stop using water and call a plumber. Don't keep plunging, since the water has nowhere to go and can come up the lowest drain.
   Done

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Watch it done

Toilet Clogs All the Time? Here's the Real FixBy Ace Hardware on YouTube. Their method may vary a little from ours.

Watch on YouTube

If it keeps clogging

If the tank is full, the jets are clean, the auger comes back empty and it still clogs, the toilet itself may be the weak link. Some early low-flow toilets from the 1990s were known for weak flushes. Toilets with the EPA WaterSense label use 1.28 gallons or less and must pass a flush test. Replacing may be worth it, but have a plumber rule out the drain line first. See how to fix a weak flush.

If the toilet gurgles or the bowl water drops between uses, the vent or the drain past the toilet is the likely problem. See the guide for a gurgling toilet and low water in the toilet bowl.

If you raised the water level or shortened the chain and now the toilet runs or refills on its own, the flapper isn't sealing. See how to fix a running toilet.