How To Fix A Slow Draining Toilet?

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Last Updated on August 26, 2022 by acechapman

Toilets rely on gravity to create a suction/siphon effect that pushes the waste out of the bowl and up the trap. To allow this to happen, both drainpipe and trap must be free from blockages. Continue reading to find out how to fix a slow-draining toilet.

A partial clog in the drainpipe or toilet trap is usually what causes slow draining toilets. A clog in the toilet trap or drainpipe can cause waste to not flow as quickly as it should. If this isn’t fixed, it could even become a complete clog. A clogged toilet could be a problem in some cases.

You can tell if a clogged vent stack is causing a slow-draining toilet. Clogged vent stacks can also cause other fixtures to drain slowly. You will also notice slow draining bathtubs and sinks.

Drain the toilet completely and then add 1 cup baking soda and 2 cups vinegar to fix it. After 15 minutes, add a gallon of hot water to fix a slow-draining toilet. You can also plunge or snake the toilet with a toilet auger. You can also unclog the vent stack.

What causes a slow-draining toilet?

Let’s now take a closer look at the causes of a slow-draining toilet.


Toilet traps are the U-shaped bend at bottom of the toilet that looks like an inverted p. This is what most people call as a “P-trap”. There are 2 reasons why every fixture in your home has a P-trap.

  • It retains a constant amount of water in the bowl, which acts as a barrier to prevent sewer gases from getting into the bathroom.
  • It traps potential clogs and prevents them from blocking the drainpipe below where it would be much more difficult to unclog.

This is why the toilet trap, unlike other drain traps, has one more important function. It is what allows the toilet to flush which is then where the siphoning effect occurs.

It has both a short and a long leg. When you flush the toilet, water quickly fills the bowl. This also fills up the trap’s shorter leg. The long leg is also filled with wastewater when this happens.

The water in the long leg will pull water from the bowl and short legs until the wastewater is siphoned off. This is how a basic siphon works.

You may notice a clog in your toilet trap and that the siphon is less powerful than it should or used to be. In this case, you might need to flush the toilet two times.


Each fixture in your home has its own drainpipe. These separate drainpipes connects further down to the drain to the main house drainage pipe, which then drains back to the septic tank or to the city’s sewer line.

A slow-draining toilet will occur if the drainpipe of your toilet has a partial blockage. The toilet bowl will fill with water when it is flushed. This causes a slow draining toilet.

Check to see if there are multiple toilets in your house. You should also check whether other fixtures, such as sinks or tubs/showers, are draining slowly.

Tree roots can sometimes cause slow draining fixtures. Tree roots in sewer lines can be fatal if they are not removed before they become too large. This will make it expensive to replace the pipes.


Vent stacks are vertical pipes that run from the drain pipe to the roof of your house. It allows sewer gases to flow from the drainpipe, and also allows for free circulation of air through the drain pipe.

Pressure buildup inside drainpipes can cause slow draining toilets. You can also see other signs of a blocked vent stack:

  • Toilets bubbling after being flushed.
  • When the toilet is flushed, the bathtub/shower drains gurgle.
  • The toilet is bubbling after the shower is finished.
  • There is a sewer smell in the home.

A clogged vent stack can’t affect just one toilet unless the problem is widespread.

slow draining toilet


It is easy to fix a slow-draining toilet. In most cases, you won’t even need to call a plumber. There are many ways to fix a slow-draining toilet depending on the cause.

These are the top five ways to unclog slow-draining toilets.


Baking soda can be considered an alkali, white vinegar is a weak acid. Both products are inexpensive and easily available. They react quickly together to produce a fizzing reaction.

This is what helps to break down the blockage in the drain line or P-trap. This works well if the blockage is caused by soap, toilet paper, or calcium deposits.

Use borax instead in place of baking soda if you don’t have it. Baking soda is weaker than borax.


  • Drain the toilet bowl. To ensure that the solution works directly on the clog, drain the entire bowl.
  • Place 1 cup of baking soda in the bowl.
  • Slowly add 2 cups vinegar.
  • Allow the solution to work for 15 minutes. Once you have done this, boil some water.
  • Place 1 gallon of hot water in the bowl. The hot water will flush out the clog and dissolve any remaining solids. It can crack the bowl so make sure to use hot water, not boiling.


Another good way to unclog slow-draining toilets without using a plunger or snake is this. Here’s how you can proceed:

  • To absorb the water from the bottom of your toilet bowl, use a sponge. Always wear gloves.
  • Place about half a cup of dish soap in your toilet bowl.
  • Bring about 1 gallon of water to boil in the kitchen.
  • Put the water in the bowl, and let it work its magic.
  • After 30 minutes, flush the toilet and see if it is draining faster.
  • This may be necessary several times to fix the problem completely.

Use hot water to unclog a toilet trap or drain pipe if toilet paper or soap is blocking it.


To break down materials in pipes, you can mix Epsom salts with warm water. You can also use drain cleaning chemicals to fix a slow-draining toilet. 

However, you should make sure to use a noncorrosive cleaner and avoid bleach. Bleach can react with other substances in the pipes and cause damage to your plumbing system.


Toilet plungers are a great tool to remove clogs from drainpipes or traps. The toilet plunger creates a pressure difference between the top of the clog and the bottom, so the pressure at its top is higher than that below.

This will force the clog to move down the drainpipe, restoring your toilet’s drainage rate.

Make sure you choose the right plunger to fit your toilet. There are two types of plungers. There are two types of toilet plungers: flat-bottomed and bell-shaped. The bell-shaped toilet plunger is the best option.

The plunger seals around the opening of the toilet bowl, allowing maximum pressure to be sent down the drainpipe. Here’s how to fix slow-draining toilets using a toilet plunger.

  • You can add water to the bowl. To plunge effectively, you must fully submerge the plunger in water.
  • Place the plunger on the toilet bowl’s opening gently and make sure it seals around it. To seal the plunger better, some people apply Vaseline to the rim.
  • Begin plunging. To ensure a tight seal, the first plunge should be gentle. For a few minutes, you can start to plunge aggressively after the first plunge.
  • Flush the toilet, father lifting the plunger.


Toilet augers, also known by the name “plumber’s snake”, are used to unclog toilets. They can either shred the clogs into smaller pieces or pull them out. It features a flexible cable, a cranking handle, and a hooked and helical head.

Toilet augers can cause serious damage to your toilet bowl if you don’t use them carefully. It comes with a guide to protect your bowl from scratches.

This is how to unblock slow-draining toilets using a toilet auger.

  • Place the cable in the tube so that the head is towards the bowl guard.
  • Slowly insert the auger into the bowl and place it in the bowl’s opening.
  • Push the cable through the trap until it becomes stuck.
  • Turn the handle counterclockwise until the restriction is gone. If the restriction feels too difficult, turn the handle in the opposite way and try one more time.
  • Once you have gotten past the restriction, or if it feels too difficult, pull the tube cable from the tube. Then remove the bowl guide and tube.
  • Once you have cleared the clog, flush it and make sure that it drains properly. If it is not, you can try again.


It is easy to unclog a vent if your toilet or other fixtures. This is how to unclog your vent stack.

  • With a garden house in your hand, climb up to the roof.
  • You can check if you have any blockages at the vent’s top that you can remove easily with your hands.
  • Use the garden hose’s end to poke the vent. It is possible to remove the clog.
  • Turn on the water supply to the garden hose. It is often possible to unclog the hose by using water weight.
  • Upgrade to a plumber snake if the water is not enough.
  • Push the snake into the vent until you encounter a restriction. Grab the handle and remove the blockage. To check for additional clogs, pull the snake out and push it back.
  • Check the water pressure in the toilet.
slow draining toilet

Slow Flushing Toilets Confusion With Slow Draining Toilets

People often confuse slow-flushing toilets with slow-draining toilets. Slow/weak flushing toilets can be caused by many factors, including clogged siphon jets and rim holes.

People who live in areas with hard water are more likely to experience this problem. Calcium and minerals, especially calcium, block the siphon jet and rim holes. This means that water from the tank can slowly enter the bowl and cause a weak flush instead.

You can solve this problem by cleaning the siphon jet and the rim holes.

A loose lift chain could also be a reason for slow flushing. The lift chain connects the toilet handle to the flapper. It should not be too loose as it can cause the flapper to fall down during flushing. The water will then drain slowly from the tank into the bowl.

Wrapping up

You’ve tried everything we have listed and your toilet still drains slowly. What should you do? You can only do one thing: Call the plumber.

Drainage companies can handle even the most difficult blockages. It is worth entrusting the problem to their skilled hands.

The professionals are experts in unblocking sinks and toilets and will be able to offer support and empathy. A blocked drain is more than just unpleasant. It can also be frustrating.

You shouldn’t leave it untreated. A blocked toilet drain can cause damage to your home or worse, your health.

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