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Toilet Running at Random? 7 Causes and Fixes

Toilet Running at Random? 7 Causes and Fixes

A toilet that runs at random can be a real nuisance. Not only do running toilets render a toilet un-flushable, but the intermittent whistling sound also is bothersome, and the unnecessary amount of water being used hikes up your water bill. While toilets only amount to 30% of home water usage, that number can increase if a toilet isn’t functioning properly. So…why is your toilet running at random, and how can you fix it?

The reasons why your toilet runs at random can stem from malfunctioning parts, such as:

  • Refill tubes
  • Flush valves
  • Flappers
  • Flush valve chains
  • Wax gaskets

Fixing a running toilet typically requires replacing some of these parts.

There’s no need to pay for excessive amounts of water you aren’t using, nor is there a need to go batty from the constant trickle of water. With that said, below is a comprehensive guide listing the seven most common causes of running toilets and how to fix them.

How Toilets Function Normally

Most people have a general concept of how toilets work. They are connected to a water and sewer line; you do your business, flush, and voila! However, many people who use them daily don’t know the exact operation and components of a toilet.

When one flushes a toilet, the handle, push-button, or pull chain motion causes a flapper component located at the bottom of the toilet to rise. This action releases freshwater into the bowl of the toilet. This is what we know as a “flush” as it flushes the bowl clean.

After the flush occurs, the flapper component will return to its original position, and the water flows into the tank (instead of into the bowl). The fill valve, which looks like a small tower, has an arm with a float attached. This float is what signals the water to stop running. When the float reaches a certain level, the tank is “full,” and the running water should cease.

Pretty simple and genius—especially considering the alternative to this was chamber pots. What a step up! However, despite how simple a toilet is, it can still easily develop problems, and often those problems result in—you guessed it—running toilets.

What Does it Mean to have a Running Toilet?

So now we know the gist of toilet function. But what does it mean when a toilet is “running” intermittently?

A running toilet refers to a toilet that allows water to flow into the tank for a longer period than is necessary or normal continually. A normal period for a toilet to refill its tank is anywhere between 15-90 seconds. If your toilet is continually allowing water to flow for longer than 2-3 minutes, you have a “running” toilet and need to investigate the cause.

How to Tell My Toilet is Running

 If the constant running of water isn’t a hint enough, you can always try this fun little trick. Add a few drops of food dye into your toilet’s water take. Don’t flush yet! Wait about 15-20 minutes. If you return to your toilet after this increment of time and notice colored water in your toilet, then this is proof you’ve got a leak!

Can I Fix it Myself or Do I Need a Plumber?

 Fortunately, not all ‘running toilet’ problems merit calling in a professional. However, as there are many causes of faulty toilets, the aim of this article is to better assist you in knowing when you can D.I.Y it and when you need to call your local plumber. If you’re more of a visual learning, House of Progress made this excellent video for the three most common causes of leaky toilets, how to fix them, and the tools you need.

If you have been fiddling around inside your toilet, altered things, removed them, or replaced them, and the toilet is still running and/or not working–then it’s time to call a plumber.

What Tools Do I Need to Fix my Toilet?

 The exact tools you need to fix your toilet will vary depending on the cause. However, there are four tools/tool kits you can guarantee will be helpful in the process of repairing your leaky toilet. Fortunately, they are simple, easy to source tools that you likely already have in your toolbox! If you don’t have them, we’ve provided some purchasable links.

Adjustable Wrench

You simply must have a wrench if you are looking to fix a running toilet. If the tank or bowl needs to be removed, an adjustable wrench will permit you to easily and successfully loosen the bolts to remove either compartment. Why adjustable? It’s important to have a wrench whose jaws can adapt to any necessary size.

This WORKPRO 4-Piece Adjustable Wrench Set is also heat-treated, chrome-plated, drop-forged carbon steel.  Each adjustable wrench has precision-machined jaws. The assorted sizes start at 6 inches, 8 inches, 10 inches, and 12 inches. The set of four is less than $25.

Long Nose Pliers

It’s likely your tool kit already has at least one size of long nose pliers. This is a useful tool, especially if the cause of the running toilet is something like a broken chain on the toilet flusher. Chains easily come undone or get unhooked from the handle levers. Long nose pliers make re-attaching the chain a cinch!

 This Long Nose Plier Set comes with heat-treated pieces. Each plier is made of drop forged high carbon steel and has comfort cushion grips. The complete set is under $25!

Galvanized Wire

A thick pliable wire, like galvanized steel, allows for you to make interim repairs to things like a toilet chain–in the event that it breaks off.  Galvanized wire is also a convenient tool to have around should the seat break, as you can push the wire through the bolt hole to reattach the seat in a matter of minutes. Of all the tools in your toolbox, this may be the one you’re less likely to have.

Not to worry! This 200-foot Galvanized Steel Wire is both tough and pliable and under $10!.

 All in One Toilet Repair Kit

Often, it’s good to have an entire kit on hand.  For one thing, you may discover that several things are causing the problem.  Or your fix might work for 6 months, and then something else needs adjusting.

This Fluidmaster Universal Toilet Fill Valve and Flapper Repair Kit is crazy convenient and crazy cheap! For $10 or less, it comes with: an anti-siphon toilet fill valve, a flapper with Microban to prevent bacteria buildup, and a five-year warranty!

Rubber Gloves

For sanitary and safety reasons, you should wear rubber gloves while fixing your toilet. To risk stating the obvious, toilets are riddled with bacteria. There is no need to shove your bare hand in any part of a toilet during an easy repair. You can purchase rubber gloves at any local grocery store or hardware store.


 Now that you know how a toilet should function, what tools you need to fix your toilet, let’s asses the various causes of running toilets, and the easy solutions to these problems.

The Toilet Refill Tube is Malfunctioning

What is a refill tube? A refill tube is a small flexible tube that replenishes the tank with water. A functioning refill tube will always remain above the water level. If it is sinking and sagging below the water level, however, it may be the source of your intermittent running water. Likewise, if the tube completely falls off, then the toilet bowl will not fill.

How Do I Fix It?

Firstly, empty the tank of water to properly asses your refill tube. To do this, you connect the toilet from the water line and flush the toilet until it drains the tank. This will allow you to better view your refill tube. If the tube has dislodged, then reattach the fill tube by pushing it firmly into place on the fill valve.

If the tube is not dislodged, but rather sagging too low, readjust it so that the refill tube is perched 1-inch over the border of the overflow tube. At this point, flush the toilet to see if the water stream from the refill tube goes down the overflow tube correctly.

Faulty Fill Valve

 The source of many running toilets is due to a faulty fill valve. If the water in your toilet is running intermittently but is not flowing to the overflow tube, it is highly probable that the fill valve needs to be replaced altogether. Fortunately, these parts are inexpensive and easy to replace without the help of a plumber.

 How Do I Fix It?

Start by shutting off the water supply valve. Next, disconnect the valve’s refill tube from the top of the overflow tube. Then flush the toilet until the tank is empty. Place a bowl or bucket beneath the water supply valve in case there is leakage. Then use an adjustable wrench on the threaded stem until it loosens. Turn the locknut to the left until it disengages from the stem. You can now lift the entire valve out of the tank for replacement.

Float Ball Malfunctioning

What is a float ball? A float ball is the small ball located inside the tank. The ball floats and sinks depending on the action occurring within the toilet at any given time. When a toilet flushes, the float ball sinks to the bottom of the tank, emptying out the tank and opening the inlet valve on the fill tube. When the toilet tank is re-filling with water, the float ball will rise again. The rising float ball causes the valve to close, which ceases the filling process.

Sometimes a float ball can become misaligned. If it malfunctions in this, or any other way, it might prevent the valve from closing off, which in turn allows the water to continually run.

How Do I Fix It?

If your float ball is misaligned, you’ll want to investigate the tank and check the height of the float. If the float and water are seated more than 1-inch from the overflow tube, the float needs readjusting. If the float will not adjust or it fills up with water, this is a sign of damage, and it needs replacing.

Improper Length of Flush Valve Chain

 What is the flush valve chain? The flush valve chain is the part of the toilet that pulls the flush valve open so that fresh water may fill the tank, while the used water flushes away. When a flush valve chain’s length is incorrect, it can interfere with the toilet’s ability to fill with fresh water and or flush properly.  When it is too long, it can get caught beneath the flapper, causing a poor seal, which in turn makes the toilet run constantly.

How Do I Fix It?

Fixing a flush valve chain is one of the easier toilet-repairs. If the chain is too long, shorten the length between the arm and the flapper.  Then grab some wire cutters and cut the excess chain off. If the chain is too short, you may need to replace the chain or temporarily install some of the galvanized wire to add length.

To install a new chain, you’ll need to shut off the water supply and flush the toilet until the tank empties. Remove the flapper. Then remove the chain from the flapper. And then install the new flapper chain. Make sure it is not too long nor too short so that you don’t need to repeat the process.

Worn Down Flapper

 What is a flapper? The flapper is a synonym for the flush valve. It is the part of the toilet that must be sealed completely after each individual flush to keep water from leaking and running. Flappers have a tendency to age poorly. Some are worn down by the mineral deposits caused by the constant contact with water. When these components wear down to the point of malfunction, it can cause that annoying intermittent water running problem.

How Do I Fix It?

Since your old flapper is not going to seal properly, it will need to be replaced with a new flapper. First, drain the water from the tank before you replace the flapper. To do this, shut off the water supply from the toilet and then flush the toilet to drain the excess water.

Then, remove the old, worn-out flapper. To do this, detach the chain and remove the flapper pins on the outside of the overflow tube panels.  Attach the new one by inserting the pins and connecting the flapper chain.

Too Much Water in the Tank

When there is too much water in the tank of a toilet, it will cause a toilet to run due to the overflow of water that is spilling from the tank into the bowl (via the overflow tube.) When there is too much water in the bowl, the water level needs to be adjusted.

How Do I Fix It?

To adjust the water level in the tank, adjust the height of the float. To do this, loosen or tighten the screw on the float arm until the float arm lowers.  If you want to lower the amount of water in the toilet tank, then loosen the screw. If you want to increase the amount of water in the toilet tank, tighten the screw.

Bad Toilet Wax Ring (Gasket)

Every toilet relies on a thick waxy gasket to prevent leaking. This gasket sits between the base and connecting flange in the floor.  The pressure of the toilet expands on the pliable wax until it creates a completely watertight seal. Of course, the downfall of a wax gasket is that the soft, malleable wax can sometimes be too pliable and eventually fail.

How Do I Fix It?

To replace the wax gasket, you must completely lift and remove the toilet from its current position to remove the old wax gasket. To do this, it’s imperative you turn off the water supply, empty the toilet tank by flushing, and get rid of any excess water. Then remove the water line from the tank. Make sure you have a towel handy as water will leak out initially. Next, use your long nose pliers to remove the screws on the bottom of your toilet (there’s two, one on either side.)

Once the screws are loose, take a razor blade and cut through the caulking connecting the toilet to the floor. Then you’ll try to loosen the toilet off the floor till you can pull it off completely. You’ll then remove the old wax seal and put a new wax seal in its place. The gasket will have two holes on either side where the toilet bolts will push through to keep it in place.

The Key Take Away?

You don’t have to be a plumber to fix a simple running toilet. Most of the time, the issue will be a malfunctioning part, many of which are cheap and easy to purchase at a nearby hardware store or online.

There are many excellent video tutorials online to help empower you to fix your own running toilet, but we do hope that we helped you uncover the several causes of running toilets, and enabled you to fix them with relative ease and newfound confidence. All you need are some tools, the knowledge of general toilet anatomy, and a little bit of bravery to dive into that porcelain throne!

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If you are interested, go check out the toilet section on Amazon for any great deals.