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Why Does My Toilet Flush Twice? Advice From The Pros

Why does my toilet flush twice

Many homeowners have experienced it before: They use the bathroom, press the handle on the toilet to flush and after the first, expected flush, the toilet spontaneously flushes itself a second time. If this is happening in your bathroom, you might wonder, “Why does my toilet flush twice?”

There are several reasons why this might happen, along with some do-it-yourself ways that homeowners can troubleshoot and address the problem. In many cases, however, it is wise to hire a professional plumber for a proper diagnosis of the issue, along with any parts installation or repairs that might be needed.

The two most common issues with a twice flushing toilet are a toilet flapper that is staying up too long or a toilet fill valve that needs to be adjusted.

If the toilet flapper stays up for too long, this is usually because your toilet has been fitted with a generic or universal flapper instead of one that was manufactured for the particular brand and model of your toilet. Generic or universal flappers are often too lightweight to drop securely back into place after a flush. Or they are otherwise unable to create a perfect seal. This means they let too much water through, forcing the toilet to flush a second time.

If the toilet valve isn’t adjusted to hold the correct amount of water, excess water will be allowed into the toilet, forcing it to flush a second time.

The good news is, neither of these issues will affect any other parts of the toilet—meaning, once you figure out what is causing the problem and fix it, that should be the end of it. Until the problem is fixed, however, you’ll probably notice at least a small increase on your water bill, since double-flushing uses more water than a single flush. In a home where the toilet is used many times per day, this extra water consumption can really add up over time. Aside from the expense and waste of extra water consumption, a malfunctioning toilet is an annoyance, plain and simple. This is why it’s smart to tackle problems as they arise and fix them before they get worse.

But to get a thorough understanding of why your toilet is flushing twice and how to fix it, you need to understand more about how your toilet works.

how does a toilet work

How Does A Toilet Work?

Despite the fact that we use our toilets multiple times a day, very few homeowners actually know how they function. Most of us don’t even think twice about how a toilet works before using it—at least, not until it starts to malfunction. Then, and only then, does the functioning of its inner structure become a point of interest.

Currently, most toilets installed in homes are gravity-flush toilets, which are a type of toilet that has been around for over 200 years. Gravity-flush toilets are made up of two main, basic parts: the tank, which holds the fresh water used to flush the toilet, and the bowl, which holds the rest of the water. The hole in the center of the basin of the bowl leads through a section below and behind the bowl called the trapway, or siphon; this leads down into the floor, where it connects to the home’s pipes.

This trapway or siphon works by creating a vacuum when water from the tank, above the bowl, is released quickly into the bowl when someone presses the handle to flush. The flushing handle is connected to a lever inside the tank that is attached to the rubber flapper by a chain. When someone flushes the toilet, the flapper lifts, allowing the water inside the tank to rush downward through the tank’s seat into the bowl.

Depending on the age of your toilet, the tank might hold anywhere from less than two gallons of water to five or even seven gallons. However much it holds, when the flapper goes up, it creates a sudden dump of gallons of water that rush down into the bowl, raising the water level there. This pressure pushes water and waste through the siphon, creating a vacuum that sucks everything down into the pipes and out of the home.

After the water from the tank has released down into the bowl, fresh water travels from the toilet’s supply valve up to the fill valve inside the tank. This is how the tank fills again between flushes, so it is ready for the next flush.

When the flapper, the float, the supply valve or any other part of the toilet breaks or stops working correctly, problems result, such as a toilet that flushes twice.

Toilet fill valve adjustment

What Happens When The Toilet Flapper Stays Up Too Long

When the flapper fits properly into the flush valve and is working correctly, it seals the hole, keeping the water inside the tank until someone flushes it. Then it drops securely back into place after the flush. The most common reason why a toilet flushes twice is because the toilet flapper stays up for too long, leaving the flush valve open and allowing too much water to escape from the tank into the bowl.

Sometimes, toilet flappers need to be replaced, even if they are the correct type for the toilet. If the toilet had a period when it was out of use for a long time, for example, with no water inside the tank, the flapper might have gotten too dry, making the rubber less supple or even subject to cracking. It is also possible for flappers to be improperly adjusted, which prevents them from sealing off the water in the tank between flushes.

You can try to diagnose the problem yourself by taking the lid off your tank and flushing the toilet. Watch what happens next—is the chain from the lever to your toilet flapper too short, making it difficult for the flapper to land back into place? Is the rubber too dry and the flapper isn’t landing effortlessly back onto the valve? Observing your toilet flapper is the best way to determine whether it needs to be replaced or just adjusted.

Homeowners can usually replace the flapper themselves, as toilet flappers are available at hardware and home improvement stores in various styles and weights that might match your toilet. If you’re going the do-it-yourself route, follow these steps:

  • Turn off the water to the toilet by closing the shut off valve.
  • Empty the tank by flushing as many times as necessary.
  • Disconnect your current flapper from the toilet flush valve by unclipping them from each other. When this happens your chain might come off, but your new flapper should come with one.
  • Pull the edges of the flapper free from the tubular overflow valve. If your flapper is made of plastic, it will make a popping noise. If your flapper is made of rubber it should slide right out.
  • Connect the new flapper to the flush valve.
  • Slide the flapper into the tubular overflow valve.
  • Adjust the chain length.

If you can’t quite tell what’s going on or you’re not sure what kind of flapper you will need, an experienced plumber can diagnose your problem and suggest an effective flapper for your toilet.

There are other reasons why a toilet might flush twice, however, that are unrelated to the flapper. Most commonly, if the water level inside the tank is too high. When this happens, it indicates that you have a toilet fill valve problem.

Toilet Flapper Stays Up

Is A Toilet Fill Valve Adjustment Needed?

A toilet fill valve adjustment will be needed if your flush is either too powerful or too weak. If this valve is not adjusted correctly, it will need to be modified so that it will let just enough water through to refill the tank.

When the water level inside the tank is too high, it creates a similar issue to a malfunctioning flapper when the toilet is flushed: Too much water rushes down into the bowl, forcing a second flush after the first one.

When the water level inside the tank is too low, there is not enough water to flush everything in the toilet bowl through the siphon, resulting in a weak flush.

It may also be time to come to terms with the fact that your toilet fill valve is old and needs replacing. How long do they last? This question isn’t as common as when to replace your air conditioner or how long do garbage disposals last, but it is an important one to ask to ensure you’re not wasting water. The unfortunate truth is that fill valves really only last for four to five years, so if you’re getting to that point, it may be time to get a new one.

Adjusting your toilet’s fill valve yourself might be a simple process involving just time and a screwdriver, or it might become more complicated. Homeowners who want to try tackling this issue themselves should research the fill valve component of their particular brand and model of toilet to make sure it’s a project they are ready to take on themselves.

Usually, if you screw your toilet valve clockwise, it will fill with more water, or vice versa. However, the amount of water you will need is going to vary, depending on your make and model of toilet. Or, you can call in a professional to handle the problem quickly and correctly for you.

Toilet Flush Problems

Toilet Flush Problems

While it’s not quite as daunting as your water heater making popping noises, toilet flush problems are still a serious issue. Toilets are used frequently in most people’s homes, even on days when only the residents of the home are using the bathroom. If your toilet is experiencing flush problems, it will be an annoyance at best, and possibly even an urgent problem that must be fixed quickly.

The flapper and the fill valve are just two components inside the toilet that can cause toilet flush problems. Other potential causes include hard water buildup inside the toilet’s pathways and pipes, which limits the amount of water that can rush through on a flush, or clogged pipes or drains due to items such as wipes or feminine products that have gotten stuck somewhere in the plumbing. (By the way, even wipes that are supposedly flushable are better off in the trash than in the toilet!)

In addition to a toilet flushing twice, a toilet that won’t stop running is another frequent problem homeowners encounter. In some cases, the culprit is the flapper, which is letting water continuously leak into the bowl. If replacing that component doesn’t resolve the issue, you may need to replace your entire flush valve assembly.

If your toilet doesn’t flush at all, it may be because the handle needs to be tightened or loosened. To tighten it, turn the nut in a counterclockwise direction. To loosen it, do the opposite. In some cases, the handle lift arm assembly is broken and needs to be replaced. Another possibility is that the lift chain has broken or tangled and is no longer attached to the lift arm or flapper, or needs to be adjusted. If your toilet doesn’t seem to flush completely, it may just be that you need to adjust the slack in the lift chain, that you need to replace the flapper or that you need more or less water in your tank.

If your toilet fills back up very slowly, it could be that your supply valve needs to be fully open. It could also be that debris in your tank is keeping the valve assembly from working properly.

Any type of toilet flush problem that you may be experiencing should be addressed as soon as possible, to keep your annoyance level down along with your water bills.

ABC Can Resolve Your Plumbing Problems

If your toilet is flushing twice, something is malfunctioning. Your toilet may need a new flapper that is designed specifically for your particular type of toilet, or it might need a fill valve adjustment or some other fix. Some DIY homeowners choose to troubleshoot and tackle these problems themselves, but for many of us, it is smarter and faster simply to call in a plumbing professional like the experts at ABC Home & Commercial Services. If your toilet isn’t working properly, we will send an experienced plumber to diagnose the problem, and we can often fix the issue in one visit. With ABC’s help, you won’t have to worry about your plumbing or spending all your free time troubleshooting any issues that might come up with your toilet.

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