Toilet Water Rises Then Slowly Drains- Causes and Fixes

Toilet issues are common, and you cannot call a plumber every time you face any issue. One of the issues people face often is a toilet that drains slowly. If your toilet water rises and then slowly drains, it can be a frustrating experience. And it can be more worrisome if you are not aware of the cause.

A toilet drains slowly when something is stuck inside the toilet causing it to clog, the vent is blocked, or when the water inside the tank is not adequate to flush. Moreover, the build-up of sediment along the rim of the toilet may block the water entrance, causing a slow drain.

Further, in this article, we will discuss the causes of the slow draining toilet and provide solutions that will help you get your toilet back to working order!

4 Reasons why the Toilet Drains Slowly

Before we jump into the solutions, let’s take a look at the reasons that may cause your toilet to drain slowly:

  • Something is stuck inside the toilet causing it to clog
  • The vent is blocked
  • The water inside the tank is not adequate to flush
  • The build-up of sediment along the rim of the toilet may block the water entrance

#1 Blockage in the Toilet

One of the primary reasons for a slow draining toilet is a blockage. And you would be surprised to know that it is quite common for the toilet to clog. In fact, on yearly basis, 20% of Americans have to deal with clogged toilets.  

When something is stuck inside the toilet the exit is blocked. When you flush, the water doesn’t suddenly drain. First, you notice a rise in water level, and then it slowly begins to drain.

too much toilet paper in the toilet

Toilets usually clog when you throw non-flushable items into them. The objects that commonly cause toilets to clog include sanitary napkins, wipes of any kind, paper towels, too much toilet paper, toys, hair, etc.

The best way to check if a toilet has blockage is to throw a bucket full of water into it and see if the water drains or not. If it doesn’t that means something is stuck inside the drain.

#2 Blockage in the Air Vent

Another common cause of a slow draining toilet is a vent blockage. The vents in your home allow air to enter the sewer system. When these vents become blocked, it can cause the water in your toilet to drain slowly. This is because the air pressure in the sewer system is not able to equalize correctly.

There are a few signs that will indicate that your vents are blocked. If you hear gurgling noises coming from your toilet when it drains, and a foul smell spreading in your bathroom. Then, probably the drain vent has been blocked.  

You may also notice that the toilet water level fluctuates and other drains in your home are draining slowly as well.

#3 Low Water Level in the tank

The third common cause of a slow draining toilet is inadequate water in the tank. When there is not enough water in the tank, it can cause the toilet to clog. This is because the water is not able to flush all of the waste out of the toilet bowl. Consequently, waste will build up in the bowl. The water will normally flow, although at a slower rate than usual.

low water level toilet tank
Image from Smithys Plumbing

To check that, first, you need to take off the toilet tank’s lid and see if it has an adequate amount of water needed to flush. Sometimes, the float ball isn’t properly adjusted causing the water to stay low, or the refill may be ruptured.

#4 Build-Up of Sediment Along the Rim

One potential cause of a slow draining toilet is a build-up of sediment along the rim holes.

Inside every toilet, you will find rim jets, that are tiny holes around the bowl’s circumference. The water from the tank enters the bowl through these holes to create a swirling motion for pushing the waste down the toilet.

But over time, these holes can become clogged with mineral deposits and other debris. As a result, water may not be able to flow freely through them and into the bowl. Consequently, you will see the bowl filling first, then draining slowly.

How to fix a toilet that drains slowly?

Now that you have come across the major causes of why might your toilet drain slowly, let’s move on to how you can fix each of these issues.

Plumber using a hand auger to snake a toilet

Fix #1: Unclog the Toilet

For unclogging the toilet, you can use a variety of tools such as a toilet plunger, toilet auger, baking soda, and cleaners.

Toilet Plunger

A plunger is a common tool that is available in most homes. So, it is a priority for clearing the blockages in the toilet.

For unclogging the toilet with a plunger insert it into the bowl. Make sure that it seals the hole and is fully submerged in water. Add more water if the water is not enough to cover the plunger.

Use Toilet Plunger to unclog the toilet

Push and pull the plunger back and forth in the bowl’s opening. Be patient and keep doing this step until the blockage is cleared. 

Toilet Auger

Another option for unclogging your toilet is to use a plumber’s snake also known as a toilet auger. This is a long, flexible piece of metal that can be inserted into the drain to remove the blockage.

use Toilet Auger to unclog the toilet

For cleaning the toilet with an auger, insert one end of the auger into the bowl. Push it down until it reaches the obstruction. Twist it and try to pass it through the obstruction. You can use the auger’s handle for twisting it.

Vinegar and Baking Soda

If you are looking for a natural way to unclog your toilet, you can try using vinegar and baking soda. This method may not work for all types of blockages, but it is worth a try.

Take one cup of baking soda and two cups of vinegar. Pour them into the toilet. Now, add half a gallon of hot water to that mixture. Let it stay in the toilet overnight. The baking soda and vinegar mixture will dissolve organic clogs. However, if any solid object is stuck inside, this method is not helpful.

Chemical Cleaners

Many chemical cleaners are also available in the market for cleaning toilets. You will easily find these in grocery stores. They can remove small clogs by chemically dissolving them. However, for bigger obstructions, you will need an auger or plunger. 

roof vent stack

Fix # 2: Clear the Air Vent

The second cause we discussed a for a slowly draining toilet for an obstructed air vent. So, if you want that the toilet keeps working smoothly, make sure the plumbing vent is fully open.

Air vents usually have an opening on the rooftop, and that’s from where they get clogged. A bird may have created a nest on the vent, or a plastic bag may have closed the vent’s opening.

So, the first thing to do is clear the vent’s opening. Next, check if the vent is clogged from the inside. If it is, you will a plumber’s snake to clear the obstruction. Follow the same steps, as you did while clearing the toilet clog with an auger.   

Fix # 3: Adjust the Toilet Float

Open the toilet to see if the water inside is adequate to flush. If it isn’t that means the toilet’s float isn’t adjusted properly.

Toilet float is usually attached to the fill tube, you can adjust its arm so that it reaches the marked height in the toilet.  However, if the float is properly adjusted, that means the fill tube is at fault, you will need to replace it.

cleaning the toilet rim

Fix # 4: Clean the Toilet Rim

The next fix you can do is clean the holes in the toilet rim. For that pour a cup of cleaner into the toilet bowl, and then scrub the holes with a toilet brush. Flush the toilet a couple of times to make sure any clog in the holes of the rim has been cleared. 

Final Words

With just a few simple steps you can fix a toilet whose water rises and then drains slowly. However, if you regularly clean the toilet properly and don’t use it as a garbage can, there’s no chance it will get clogged.  

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