Troubleshooting a Toilet That Won’t Flush

Plumber Repairing Toilet
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Since Roman times, the commode, or toilet, has been an important fixture. The modern toilet is one of the most fundamental necessities in your home, and while the design hasn’t changed much, the amount of water required and overall efficiency have. Unfortunately, toilets remain prone to a number of issues which may hinder or even prevent them from flushing properly.

The immediate reaction is to call a professional, although the simplistic design of a toilet means you can usually repair them yourself with little or no experience.

Toilets 101

Toilet Tank Mechanism
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Most issues caused by your toilet are easily fixed without requiring a plumber. In fact, even amateur DIYers can replace a toilet with minimal research or tools. Understanding how your toilet functions is an important part of diagnosing any issues quickly.

Anatomy of a Toilet

There are three major parts of the traditional toilet, along with a handful of sub-assemblies. Modern bidets have a more complicated makeup and are often automated or are only partially visible. For this reason, it is often best to hire a professional if a bidet issue isn’t easily accessible for repairs.

  • Tank: The tank is usually located directly on top of the bowl, although some models have it suspended from the wall. It contains one major sub-assembly that keeps the tank full, as well as a stopper (known as a flapper) for draining water into the bowl. The handle or pull chain is connected to a bar on the inside of the tank, which is attached to the flapper by a chain. Tankless toilets rely upon water pressure to perform this task and may use a pump when pressure is otherwise too low.
  • Bowl: When thinking of a toilet, this tends to be the first image conjured. A bowl has no complex mechanisms or sub-assemblies beyond the toilet seat, and consists of the bowl and an S-shaped drainpipe known as the bowl siphon. The bowl is affixed to the floor using a rubber or wax ring as a seal.
  • Trap: Under the toilet are the sewer line and a valve known as the trap, which is designed to prevent septic water from back-flowing into nearby drains, such as your sink or bathtub. This section of pipe, as well as the bowl siphon are the two most common locations of clogs.

How Toilets Work

While there are some variations in design, the basic functionality of toilets remains the same. When you pull the handle (or chain, for an overhead tank), the handle arm inside of the tank lifts, raising the flapper. This stopper is lightweight and remains floating until the water inside the tank has drained, dropping it back into place.

As the water level lowers, the ball float sinks, triggering a valve which begins refilling the tank. The valve closes when the ball float raises back to a preset angle. In the event of a problem with the float, an overflow tube drains excess water safely into the bowl to prevent flooding.

Meanwhile, the water draining from your tank enters the bowl through small openings under the rim, as well as a larger hole at the bottom of the bowl, known as the siphon jet. Rising pressure from the sudden influx of water eventually pushes the water over the bowl siphon, and suction pulls the remaining water and solid waste down the drain.

As waste is pulled through the bowl siphon into the sewer pipe, a trap valve closes off the connected drainpipes from your sink and tub to prevent any back-flow into those fixtures.

The Toilet Won’t Flush at All

Toilet Handle Being Pushed to Flush Toilet
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One frustrating scenario some homeowners encounter is the complete failure of a toilet to do anything when they pull the handle. This problem may be a simple fix, but often points to one or more of the tank components needing replacement.

Is the Shut-Off Valve Open?

Like most people, you probably haven’t paid any attention to the little valve located behind the toilet. This valve controls the amount of water going to the tank, and can be used to not only stop the flow of water during maintenance, but can also affect the water pressure.

Sometimes, the valve can get bumped or shifted when you’re cleaning or if you keep objects beside it, causing it to partially or fully close. Making sure the valve is turned fully counter-clockwise will ensure that it’s open and not preventing your tank from filling.

Checking the Tank

In most cases, the problem can be found in your toilet’s tank. Problems in the tank can happen because of calcium buildup, corrosion, or damaged parts. Replacing individual parts in the tank can generally be done at low cost with a trip to your local hardware store and the aid of a screwdriver.

  • Flapper Assembly: Perhaps the most common culprit, the flapper is attached to your tank’s handle arm by a chain. This chain can sometimes become unhooked through rough usage. You may also discover the chain or handle arm has broken, which requires that part to be replaced. Finally, the flapper itself may be stuck due to corrosion at the joint or warping.
  • Float: In a case where the tank is empty and the float is up, check for signs of corrosion where the float is attached. As this is the component which causes the refill valve to open and close, it is important to make sure it moves freely and isn’t damaged in any way.

The Bowl Doesn’t Drain Properly when Flushing

Toilet Draining Water
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One of the most common issues with toilets is a failure to drain. This may be caused by a few different issues, each of which has a simple solution.

Check the Shut-Off Valve

The shut-off valve is often your first suspect in a flush failure. Check the valve to make sure it is fully open by attempting to turn it counter-clockwise. A partially closed valve will reduce water pressure to the tank, which in turn can affect the efficiency of each flush.

Check for Clogs

Toilets rely upon gravity to properly drain. When there’s a clog in the line, your bowl will fill and the resulting pressure will wedge the clog further in place. Dealing with clogs is fairly simple and can usually be handled with a plunger.

In the event you’re unable to remove the clog this way, you may need to use an auger. Successfully draining the bowl from plunging should be followed up by a test flush to monitor whether there is still an obstruction delaying proper drainage.

Testing the Flapper

Inside the tank is a rubber stopper known as the flapper. When this becomes warped, it will fail to raise and lower properly, preventing the tank from properly draining. Getting stuck in the open position prevents the tank from filling, while a loose flapper will close before there is enough water in your bowl to complete the flush. Flappers are relatively cheap and easy to replace, and are available at most hardware stores.

Line Clogs and Septic Systems

When the toilet fills and then drains slowly, it can be a sign of a clog further down the sewer line which may be reachable only by an auger or chemicals. In the event you have a septic system instead of being on a municipal sewer line, this can also be a sign that your septic tank is full or needs cleaned. In both of these scenarios, it will be necessary to contact a professional.

The Toilet Doesn’t Flush Waste Completely

Of all the possible flushing malfunctions, perhaps the most dreaded is a toilet which only partially flushes. Large amounts of solid waste can require a second flush to completely clear, but what if the problem is ongoing? There are two major culprits for this problem.

Low Water Pressure

Your toilet relies heavily upon pressure to function, and a large volume of water must enter the bowl at once to fully drain it. If you pour a bucket of water into the bowl and it flushes the solid waste easily, the problem lies somewhere in your tank or the overall water pressure.

As mentioned before, you should check the shut-off valve and the flapper to make sure there are no problems. You may also wish to use a mirror to check the rim holes to make sure they are not partially clogged by calcium or mineral buildup.

Partial Obstructions

A partial obstruction, especially at the trap, can allow water to pass freely while slowing solid waste. Using an auger to break up any blockages will usually work where a plunger might have little or no effect. Small objects, such as pencils or crayons are common culprits. In the event an auger or chemicals fail to remove the obstruction, you will need to contact a professional.

A Quick Note on Tankless Toilets

Tankless toilets save space, but rely even more heavily upon water pressure than a regular toilet. Check neighboring faucets for low water pressure. In most American homes, tankless toilets are assisted by a pump, which may require professional handling in the event your water pressure elsewhere has not decreased.

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