Here’s Why Your Toilet Is Not Flushing All the Way

If you’re like most people, you hardly give your toilet a second thought. You use it daily and clean it regularly, but other than that, your toilet should do its job, without fail, whenever you need it to. 

Unfortunately, your toilet isn’t infallible. It has mechanical parts that can and do wear out from time to time. When they do, it can leave you with an embarrassing, and sometimes messy, problem on your hands. 

One common problem is when a toilet is not flushing all the way. This can happen for several reasons including weak water flow or worn parts. I’m going to go over the causes of a toilet not flushing fully and what you can do to fix the issue once and for all. 

Most of the solutions I’m going to talk about aren’t difficult to implement, so you should be able to complete them yourself and get your toilet back up to full flush. 

How To Fix A Toilet Not Flushing Fully

For this article, I’m going to assume you don’t have an outdated low-flow toilet. These toilets often have incomplete flushing problems simply because they are designed to use as little water as possible to get the job done.

Having established that, let’s move on to the most common reason a toilet doesn’t flush fully: a clog. Of course, there are other reasons your toilet may not be flushing completely, but removing a clog is the easiest and quickest resolution, so that’s where I’ll start. 

Is Your Toilet Is Clogged

The most common reason a toilet doesn’t flush properly is a clog. Most toilet clogs occur in the trap, which is the curved part of the toilet drain that holds a tiny bit of water to keep sewer gases from rising up and into your home. 

Because of the shape of the toilet trap, many things can get caught there including waste, toilet paper, and other materials that might get flushed either on purpose or accidentally. Toilet paper is designed to dissolve in water, but most other things are not, and they end up trapped in the trap. 

The easiest way to coax a clog along is with a plunger. Plunging the toilet pushes down anything in its path, clearing the way so the toilet can return to full flush. If a plunger doesn’t work, you may need to use more aggressive means such as a toilet auger to remove the clog.

The Toilet Won’t Flush and It’s Not Clogged

Sometimes a toilet won’t flush even though no clog is present. This means something else is wrong, and it is most likely to be a result of worn parts or some sort of mechanical issue in how the parts are functioning within the water tank. The flush components of a toilet header tank are made of plastic, metal, and rubber – all of which can deteriorate and wear out over time. When this happens, you could end up with weak water flow in your toilet that doesn’t fully remove waste with a single flush. There are several areas to check for wear inside the tank. 

Worn Flapper Seal

The flapper is that large, round rubber piece you see at the bottom of the toilet tank. Its job is to allow water to pass from the tank to the bowl when the handle is pushed down. When closed, it forms a watertight seal. If the flapper becomes damaged or deteriorated, it can leak, which results in low water pressure when the toilet is flushed. The good news is, replacing the flapper is a cheap, and simple fix. 

To diagnose a worn flapper, take the top off the tank and listen closely. If water is leaking from a worn flapper, the toilet may run more often or constantly. If this is the case, you need to head to your local home improvement store to pick up a new flapper and follow its directions to install it. 

schematic showing flapper  Toilet Is Not Flushing All the Way

Flapper Chain To Long

The flapper chain connects the handle to the flapper. While you are inspecting the flapper, make sure the chain is the right length to allow the flapper to open and close properly. 

The chain should be long enough that it allows the flapper to close completely at the end of each flush, but short enough that it pulls the flapper up to allow water to flow through. If the chain is too long or too short, the toilet won’t be able to flush properly. With the tank cover removed, flush the toilet, and observe how the chain lifts the flapper. If its length isn’t allowing the flapper to open and close fully, adjust the length of the chain. 

Note: Flapper chains are usually made of metal or plastic, which means they can deteriorate over time. They may break and need to be replaced to return the toilet to full-flush capacity. 

Problem With The Flush Handle Fitting

Toilet handles get a lot of use, so they can become loose or broken. If the flush handle on your toilet is loose, it may not be lifting the flapper fully. Tighten the handle fitting. If it won’t tighten or won’t stay tightened, you can find replacement handles at your local hardware store. 

Fill Float Not Set To Correct Position

When you flush your toilet, the fill float tells the toilet when to stop filling. This float often looks like a ball, which is why it is also called a ball float. When the float reaches the fill line, it stops the water flow into the tank. Sometimes, however, this float can become damaged or misaligned, causing it to shut the water fill off too soon. If there isn’t enough water in the tank, your toilet will have weak water pressure and won’t be able to flush all the way. 

Again, if the float is damaged, your local home improvement store will have replacement parts. If the float is just misaligned, simply adjust it to allow more water to flow into the tank before the float shuts the water off. 

Clogged Rim Inlet Holes

The rim inlet holes are located inside the toilet bowl just under the rim. They allow a concentrated flow of water to enter the bowl from the tank to swirl the contents of the bowl and flush it away. The holes can become clogged with mineral deposits, waste, and other debris, which causes the water flow to be weaker than normal. 

Keeping to a regular cleaning schedule for your toilet can help keep the rim inlet holes clear, but if you suspect this to be your issue, use an old toothbrush and some undiluted white vinegar to clean the jets so water can flow freely. 

Verdict: Toilet Won’t Flush All The Way

Most of us don’t give our toilets a second thought. That is until they stop working correctly for some reason. As you can see, a toilet that doesn’t flush all the way can be frustrating, but there’s often a simple fix that almost any homeowner can do themselves. 

The first thing to do is figure out why your toilet is not flushing all the way. The culprit could be a simple clog, or it could be something more involved such as a worn flapper, flush handle and chain issues, clogged rim inlet jets, or a misaligned or worn fill float. Hopefully, the information I provided above helps you diagnose your toilet flush issues and gives you direction on how to resolve these issues. If none of the things I’ve mentioned above fixes your incomplete flushing problems, you may need to call in a professional or replace your toilet. 

How Do I Make My Toilet Flush Stronger

A properly functioning toilet should have a flush strong enough to move toilet paper and waste adequately. If your toilet used to flush well but now it doesn’t, there are a few things you can do. 

  • Check for and clear any clogs.
  • Increase the tank’s water level by adjusting the fill float.
  • Check for and clean mineral deposit buildup.
  • Clean waste and/or other debris from the rim inlet jets.
  • Check for and replace any worn or damaged parts inside the tank.
  • Call in a plumber to diagnose and fix the incomplete flushing issue. 
  • Consider upgrading your toilet, especially if your old toilet is an outdated low-flow model.

You may also like to read Toilet Leaking From Water Supply Line | Here’s The Fix

Plumber and HVAC Technician | Website | + posts

As a retired Master Plumber Jamie has over 30 years of hands-on experience, making his plumbing knowledge second to none. He has also worked on both residential and commercial HVAC installation and repair projects.