The toilet is an incredibly important element of any home. After all, an average human goes to urinate at least four times a day and to void their bowels at least once within 24 hours. So, it’s only natural that there will be some problems with the toilet every now and again. Maybe it runs randomly, or gurgles during a flush, or, in relation to the topic of this article, the water in it rises but slowly drains later. 

So, why does that happen, exactly? Well, there are multiple reasons behind this occurrence, and we will cover them in the paragraphs that follow. In addition, you will learn how to unclog your toilet if anything similar is going on in your bathroom.

What Causes a Toilet to Slowly Drain?

There are four main causes behind slow drains:

  • Blockage or build-up in the drain
  • Low water levels in the water tank
  • Mineral and/or sediment build-up along the rim
  • Cracked toilet bowl

Blockage or Build-up in the Drain

Clogged toilets are a lot more common than you think. According to one survey, almost 20% of Americans have to deal with this issue on a regular basis. And generally speaking, everyone knows what a clogged toilet looks like. You don’t exactly need to know your toilet inside and out to see that the water is overflowing and not going away.

This type of clogging usually occurs within the bowl, maybe a few centimeters down the drain. However, if the blockage happens further down the drain, within the system itself, it can become a major issue. Generally speaking, the reason behind such blockages is waste and toilet paper, among other things, building up within the pipes and preventing the water from going through fully. That actually results in the water not draining away any faster, even after days of flushing.

There’s a straightforward method of checking whether your drain system is clogged or not. Simply take a gallon of water and pour it into the bowl. If the water goes down without any issue, then your system is fine, or maybe it has just a small clog. On the other hand, if the water doesn’t sink or if its level immediately rises, you need to call an expert or, alternatively, try to unclog the toilet yourself.

Low Water Levels in the Water Tank

Interestingly, slow drainage isn’t necessarily related to the toilet bowl or the drain system. In fact, it might have to do with the water tank. More specifically, it could be related to the amount of water that the tank contains.

When you notice a slow draining of water after flushing, wait for the tank to stop refilling, then open the lid. Pay close attention to the inside of the tank. Is the water level higher or lower than usual? If the answer is the latter, then you’ve located the problem.

Without sufficient force, water is simply not reaching the bowl fast enough to push the waste down the drain. For that reason, waste will accumulate in the bowl until the toilet stops flushing properly. And since the problem is not related to drain clogging, the water will naturally go away but slower than usual.

Now, solving this issue can be rather simple. Maybe it will be as simple as adjusting the water level manually. Of course, there are some water tank issues that are beyond the homeowner’s control. After all, as is the case with every other item in the house, water tanks break down. Therefore, you will either have to replace certain parts or buy a new water tank altogether.

Regarding this problem specifically, slow draining from the water tank can be the result of several issues:

  • Broken refill tube
  • Damaged fill valves
  • Cracked tank.

More often than not, you will be able to handle replacing these parts yourself. However, we still recommend calling an expert plumber to do the job properly.

Mineral and/or Sediment Build-up Along the Rim

Every single toilet bowl has something called rim jets. Simply put, they are tiny holes that are located on the underside of the toilet bowl rim. Water from the tank actually runs through these holes in order to create a swirling motion, which helps push the waste down more effectively. So, keeping them well maintained is just as important as keeping the tank and the drain in working condition.

More often than not, the water you flush down the toilet will be hard, i.e., it will have lots of minerals like calcium and magnesium. Over time, these minerals will accumulate in and around the rim jets. The more they do, the more they will obstruct the water and prevent it from passing. For that reason, water will flow more slowly than usual, resulting in the bowl water level rising and subsequent slow drainage.

Cracked Toilet Bowl

Interestingly, toilet bowls do not crack as often as you might think. In fact, out of all the problems we’ve listed in this article, spotting a crack within the lower section of the bowl is the rarest. But it does occur, and once it does, you will have to tackle the issue head-on.

Still, how does a cracked bowl factor into slow water drainage? Well, the water from the tank will slowly drip away through the bowl’s crack and straight into the lower bowl. This will keep happening until the water level in the lower bowl increases. You will also see a lot of water around the base of the bowl, which is an issue in and of itself. Namely, the more moisture you get, the higher the possibility of mold and mildew growing around the toilet base, as well as within both the bowl and the tank.

How to Fix a Toilet That Drains Slowly

As we stated earlier, the best possible option is to call a professional plumber who can pinpoint the exact problem with your slow-draining toilet. Of course, if you’re set on fixing the toilet yourself, there are certain steps you can take to prevent water build-up. Naturally, you’ll have to learn everything you can about a basic toilet and its working parts before you do anything major.

Replace the Cracked Bowl

In order to handle the problem of bowl damage, lots of people tend to somehow seal the crack. However, any method of sealing will be temporary at best. And yes, that also includes using waterproof epoxy, which is an option many different articles across the internet recommend.

Still, if you need a temporary solution, you can try and utilize the epoxy. Nevertheless, there’s no real method of permanently fixing a crack. In other words, you will have to buy a new toilet bowl and replace the current one.

Remove a Damaged Refill Tube

We’ve already mentioned refill tubes earlier. In a nutshell, they are small, black, and rubbery tubes that are easy to spot in every tank. They are always connected to a big, wide vertical tube called the overflow tube. 

The job of the refill tube is to transfer water from the tank to the bowl. And considering how many times you flush a day (and assuming more than one person lives in your home), these tubes will eventually show signs of wear and tear. The damage can cause the tube to unclip, which will lead to the tank filling up and the valve shutting off.

When this happens, water will slowly start filling up the bowl, at which point you will want to inspect the refill tube. If it looks decent enough, you only have to reattach it onto the cylinder, and it will resume working just fine. However, if the tube looks worn beyond repair, you will want to replace it. They usually don’t cost a lot, and you can buy them from any online retailer.  

Use a Plunger

Moving away from the tank to the bowl, the reason behind the slow drain might simply be clogging. In order to get rid of stubborn clogs, you will need a decent plunger that’s appropriate for your toilet. And remember, not all plungers are the same. So, you will need to find the right one if you don’t want your unclogging to be messy.

First and foremost, position your plunger in such a way that the rubbery section covers the opening completely. You will want a good tight seal when you plunge. Furthermore, don’t forget to wear gloves, just in case something goes wrong.

Your first plunge will have to be slow and gentle. After all, the plunger is full of air, and if you try to force it down the toilet bowl opening, you risk spraying water and waste all over yourself or any nearby objects. Of course, once that initial plunge is over, you can thrust faster, but don’t go overboard.

One of the key points of plunging is that you must not break the seal once you have it. In addition, you will need a lot of patience. Stubborn and massive clogs can take up to 30 minutes of solid plunging to clear. And more often than not, even that won’t work, so you might have to move to different unclogging methods.

Handle a Blocked Sewer Line Vent

Sewer line vents, also known as plumbing vents or vent stacks, play a key role in your home’s plumbing system. First and foremost, they make sure no gas or odors stay within your home. However, their secondary role is to allow fresh air to enter the plumbing system. Said air then helps the water flow smoothly down the drain pipes during a flush.

Because of its role, a sewer line vent is usually located on the roof, exposed just enough to let the air in and out. Sadly, that will often result in various debris, such as dust, dirt, twigs, branches, rocks, and even dead animals, entering the pipe. No matter what the obstruction is, it will prevent air from flowing into the drain system, thus making the water in the bowl run slower than usual.

If you prefer the DIY method of doing things, the first thing you’ll want to do is access your rooftop and inspect the top of the vent. If the obstruction, like a plastic bag or a piece of cloth, is on the surface, simply remove it and try flushing again later.

Of course, the clog could be deeper in the vent. So, we advise you to take a flashlight and a plumber’s snake with you when performing the check. If you can see the obstruction down the vent, use the snake to dislodge it. Should that not work, call a professional as soon as possible.

Unclogging with Chemicals Found Around the Home

Some households don’t have a plunger available when their toilet has a clogging problem. Instead, you can use different chemicals, such as drain cleaners and dish soap, that you can find around your home. However, the way you use them will vary depending on your situation.

Before starting the procedure, you will need the following:

  • A decent drain cleaner for toilets
  • Any dishwashing soap
  • Hot water

If you happen to have a new toilet bowl, you will first want to pour in a gallon of hot water and let it sit there for a while. Oftentimes, the hot water itself will dissolve the obstruction, and all you have to do is flush afterward. However, if you have an old toilet made of porcelain, hot water might cause it to crack, so we recommend using lukewarm water instead.

If the water itself doesn’t do the trick after some time, take a small amount of toilet drain cleaner and pour it into the bowl. Depending on the product instructions, you will either flush immediately or wait for a specific amount of time. 

After doing all of that, take a tablespoon of dishwashing soap and pour it down the overflow pipe in your water tank. It should take about 10 minutes for the soap to seep down the pipe. During that time, it will remove small sections of calcium deposits that were building up due to excessive use. Once the 10 minutes have passed, you can flush the toilet safely.

Replacing the Fill Valve

Out of all the issues mentioned in this article, a damaged fill valve will probably cause the most problems in your home. Namely, it can lead to excessive flow of water down the drain, making your water bills skyrocket. So, before you do anything related to the fill valve, you will first need to shut off the water supply to your toilet.

Your next step is to drain the remaining water from the tank by flushing the toilet. Use an old cloth or a rag to mop up any remaining liquid in the tank. Once you’re done, unscrew the nut that connects the fill valve to the water hose. Next, pull the old valve up from its base and insert a new one in.

Finally, your valve will need to be secured. Using a wrench, secure the nut under the valve and reattach both the refill tube and the water supply hose. Just to be on the safe side, turn your water supply back on and test the flushing system a few times. If the problem persists, call the plumber.

Final Thoughts

As you can see, more often than not, the slow draining issue can be resolved with a simple DIY trick. However, the key takeaway is that you should address the problem as soon as possible.

Quite often, people let the water stay in the bowl in hopes that it will unclog itself over time. And while that might work for some toilet models and drain systems, it’s not a perfect solution, and you’ll have to try one of the other methods this article covers.

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