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Toilet Flushes Slowly and Incompletely (This will FIX it!)

Toilet Flushes Slowly and Incompletely (This will FIX it!)

Toilets are a crucial part of any home. That’s why it’s fundamental to always have a well-functioning toilet. But sometimes, even with the best care, our toilets can develop flushing problems, often leaving us frustrated. So, what could be the reason your toilet flushes slowly and incompletely?

A toilet that flushes slowly and incompletely can be due to a clog, component failures, or a problem with the water supply. Try to pinpoint the source of the problem immediately after you notice the problem. Only after you identify the cause can you determine the best way to fix it. Otherwise, the situation may worsen over time.

Slow and incomplete toilet flushes aren’t uncommon. It’s a problem thousands of homeowners all over the world have to deal with each day. So, don’t panic. Herein, we’ll examine the possible causes and suggest a way out. And just so you know, there’s a lot to learn here, so you can’t afford to miss a thing.

Reasons Why Toilet Flushes So Slowly and Incompletely

The reason your toilet flushes so slowly and incompletely can be either low water level in the tank, drain blockage, or clogged rim holes. These three are the most likely suspects. So, take time and go through each of them to see which one is your case.

Let me take you through each of these causes one by one.

1. Partial Drain blockage

It’s the most common reason behind a toilet flushing slowly and incompletely. The S trap, the section of the drainpipe under your toilet, has a curved design, making it easy for objects to get stuck in it. And yes, the “objects” in this case can really be anything, from toys your kids flushed by mistake to large wads of toilet paper.

But again, the S trap isn’t the only likely problem area here. Blockage could also occur deeper in the drain system. So, if you’ve checked the trap and found it clear, but your toilet is still flushing slowly, a blockage could have occurred elsewhere.

And just so you know, draining slowly is a sign of partial blockage. A wholly blocked drain won’t drain at all. So, if your toilet is flushing but draining slowly, if the problem has anything to do with blockage, then it’s partial.

2. Low Water Level in the Tank

Yes, inadequate water in the tank could be the reason behind the weak flushes you’ve recently noticed in your toilet. Your toilet uses a certain amount of water and gravity to generate enough power to clear the bowl. If there’s insufficient water, the toilet can’t flush as it should.

So, if toilet flushing slowly is your current problem, first inspect your toilet tank. And don’t worry – it’s easy; remove the toilet tank lid and check the water level. If your tank has a water-level line, check to see if the water has fallen below it.

If the tank doesn’t have this line, it’s still okay. Check the water level relative to the top of the overflow pipe. A healthy water level should be between 1/2 an inch and an inch below the overflow pipe. If it’s below that, you probably have already diagnosed the problem.

Now, there are several reasons why the water in your tank could be low, but that has much to do with faulty tank components, but more of that will be coming later.

3. Clogged Rim Holes

The rim holes are the small holes around the toilet bowl’s rim that help flush water into the bowl. And when these get clogged, they’ll impede the water flowing from the water tank into the toilet bowl, resulting in a weak flush.

Let me use a classic kitchen example. If you’ve ever filtered tea into a cup or flask, you know how a partially clogged filter slows down the filtration process. Clogged rim holes have the same effect on toilet flushing. They don’t filter in this case, but they sit between the tank and the bowl. So, if they’re clogged, they’ll weaken the flush.

Now, there are two common causes of clogged rim holes;

  • Mineral deposits arising from too much hardness in your water supply. Over time, the minerals build up and clog the rim holes. Usually, mineral deposits will appear scaly.
  • Bacteria buildup It emanates from poor hygiene around the toilet bowl. If you don’t clean the bowl and the rim regularly, bacteria will build up and clog the holes. As for bacteria buildup, it appears as black spots beneath the rim. However, it can also have a dark orange color.

So, if the cause isn’t low water level or clogs, the little jets underneath the toilet bowls could be the culprits. Take time and scrutinize them. You can use a mirror for a better view. If you find them clogged, then that could be the reason your toilet flushes slowly and incompletely.

4. Faulty Parts in the Flushing Mechanism

Mostly, this problem will correlate with low water levels in the tank. So, if you’ve been noticing that your toilet flushes slowly and incompletely, and you’ve checked the water level and found it to be low, then faulty parts could be the actual cause.

The thing is, proper water level regulation requires all the tank parts to be in good working condition. And if any of these parts is faulty, the first thing you’ll notice is the low water level in the tank. It’s from there that you can do those slow and incomplete flushes.

Here, begin with the most critical components; the fill and the flush valve. If either is faulty, it can cause your toilet to flush slowly and incompletely. Other parts to examine here include the flapper valve and the ball float.

If they all seem to be in good working condition, but the water level suggests otherwise, divert your attention to the tank itself. It could have cracks that allow water to escape.

How To Fix a Toilet That Flushes Slowly?

How you fix a toilet that flushes slowly will depend on what you found to be the problem. The solution could be as easy as plunging or as demanding as replacing faulty parts. Whatever the problem is, don’t worry! You can fix it quickly if you know what to do.

Here is a summary of some of the most effective fixes for toilets that flush slowly;

1. Use a Plunger

If the problem has anything to do with partial obstruction, a plunger should fix it. Plungers aren’t the best for shower clogs but believe me, it’s an entirely different story when it comes to toilets.


1.    Ensure that the water in the bowl covers the plunger’s cup

2.    Place the plunger over the drain hole

3.    Pump for about 15 seconds without lifting the tool from the hole

4.    Lift the plunger and check to see if water is draining from the bowl

5.    Repeat if necessary

2. Replace the Faulty Parts

Where the problem is with a faulty part in the flushing mechanism, your best bet would be to replace that part. The most common culprits include the fill valve, flush valve, ball float, and flapper valve.


1.    Disconnect the main water supply

2.    Empty the tank by flushing what’s already there

3. Replace the faulty part: You may need a screwdriver depending on the component you’re replacing.

4.    Turn your water supply back on

5.    Flush the toilet

3. Clear the Clogged Jet Holes

Suppose the problem has something to do with clogged jet holes, the only way to have a well-flushing toilet is to clear those holes. Here, the procedure you use for clogs caused by hard water deposit is slightly different from that for clogs caused by bacteria buildup.

For deposits:

1.    Heat 15 ounces of vinegar to about 120 degrees Fahrenheit.

2.    Pour it into the overflow tube in the water tank

3.    Wait for at least an hour

4.    In the meantime, try to poke the holes with a wire to loosen the deposit.

5.    Flush the toilet

6.    Clean the underside with a toilet cleaner

7.    Flush again

For Bacteria:

  1. Add bleach solution into overflow tube: Use 1 part of bleach for every 10 parts of water.

2.    Wait for about 15 minutes

3.    As you wait, use wire and mirror to clear the holes

4.    Flush

5.    Work on the underneath using toilet cleaner

6.    Flush again

How Do You Unclog a Slow-Draining Toilet?

You can unclog a slow-draining toilet using a plunger, plumber’s snake, standard household products, or even a power flush. And as usual, you can always involve a professional if you think the problem is out of your league.


1. Yes, Plunger Again

This is probably the most common way to unclog a toilet. All you need is a toilet plunger, and you’re good to go. As for the procedure, it’s similar to what we discussed earlier on. Just ensure that you don’t pump too hard. Otherwise, the water may splash out of the bowl, and you definitely don’t want that.

2. Use a Plumber’s Snake

If a plunger doesn’t seem to do the job, you may need a toilet auger or plumber’s snake. This is just a long, flexible wire with a handle. The wire comes in varying lengths for different applications, but the standard cable length is 25 feet long.


1.    Insert the auger into the drain

2.    Push it down

3.    Twist until you feel resistance

4.    Retract the snake to bring up the stuck debris

5.    Repeat until you’ve removed most debris

6.    Flush the toilet

3. Deploy Hot Water Bucket Method

It’s one of the most common and straightforward methods. You need a bucket of hot water, dish soap, and you’re good to go.


1.    Using a bucket, pour hot water into the toilet bowl.

2.    Pour dishwasher soap into the overflow tube

3.    Add drain cleaner into the overflow tube

4.    Wait for 15 minutes

5.    Flush the toilet

4. Use Baking Soda and Vinegar

These two staple household items can also come in handy when unclogging a toilet. The duo will produce a foamy mixture to help push the clog down the drain.


1.    Start by pouring a cup of baking soda into the bowl

2.    Follow that up with a cup of vinegar

3.    Wait for a few minutes until you see the foamy mixture

4.    Flush the toilet

5.  Perform a Power Flush

Sometimes, a simple flush isn’t enough. In such cases, you may have to do a power flush. This procedure involves holding the flush handle for longer periods than usual to ensure enough water enters the bowl to push the clog down the drain.

Of course, doing so won’t save you water. But if you have to flush your toilet a couple of times every time you use it, that’s neither efficient. But then again, a power flush will serve as a temporary solution as you find one for the long term. Otherwise, you may expect to spend more time and money on your toilet than you’d like.

6. Call a Professional

Lastly, you can always involve a professional when you think the problem demands professional intervention. Plumbers have the necessary tools and experience to diagnose and quickly solve any issues arising from your toilet.

Why Does The Water in My Toilet Bowl Slowly Go Down?

The water in your toilet bowl may slowly go down because of partial blockage or improper venting. When there’s partial blockage, the water you flush faces much resistance as it tries to go down the drain. This is because something is blocking the way.

As for improper venting, it occurs when the vent pipe that goes to the roof is blocked. This blocks the flow of air and slows down the water drainage. In some cases, it may even cause complete drainage stoppage.

As for the partial blockage, you already know what to do. But if it’s due to improper venting, then still don’t worry. This article will guide you on checking if the vent pipe is the problem and what you can do about it.

Final Verdict

If your toilet flushes slowly, it really could be anything from a simple partial clog to a faulty part to a low water level. Though there are many potential causes, thankfully, there’s usually a simple solution. How to go about it depends on the cause of the problem and its severity. But you can often fix the issue without calling a professional. So, save time and money, and try one of the solutions above.