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We’ve all experienced it before – flushing a toilet only to have it continue running for what seems like forever. You stand in front of it staring perplexingly ready to jump into action if anything goes wrong. Even if there are no busting pipes or overflowing, this continuous running is still a symptom of a deeper problem which also decreases your home’s water efficiency. Here, we’re going to take a look at some potential causes and provide you with the steps you need to fix it.
What are the key parts of a toilet?
Before you can properly diagnose and fix a running toilet, it’s important to understand the basic anatomy of a tank. Here are the most important parts to know:
Flush Lever – This is what you push down to flush the toilet. It’s connected to an extended arm on the inside of the tank that lifts up the rubber flapper allowing water to flow into the drain.
Rubber Flapper – Located at the base of a tank, this piece prevents water from draining except when the toilet is flushing.
Flapper Chain – This chain connects the flush lever with the rubber flapper. When you push down on the flush lever, the extended arm inside the tank pulls on the flapper chain to lift up the flapper.
Pump – After a tank has been drained from a flush, the pump is triggered to refill it.
Float – This important device tells the pump when to stop filling the tank to prevent overflowing.
4 Reasons Your Toilet Keeps Running
The flapper chain is too short.
The flapper chain needs to be the perfect length to lift the rubber flapper enough for the water in the tank to drain when the lever is pushed. When the chain is too short, it can’t seal the drain properly, causing the water in the tank to drain continuously even when the lever isn’t engaged. A shortened flapper chain can result from entanglement or a design flaw. To diagnose this issue, remove the lid from the tank and inspect the flapper chain. If it’s caught on something, untangle the chain to see if it seals the drain. You might have to get a replacement if the chain is simply too short.
The flapper is compromised.
Even the highest quality and properly sized flappers will eventually struggle to seal the drain due to usual wear and tear. Dirt and other debris can create big enough gaps for water to seep through, and flappers can become warped and damaged from constant use. Fortunately, it’s pretty easy to clean or replace a flapper. Simply drain the tank and unhook the flapper from the flapper chain. If it looks salvageable, give it a good clean and retest it to see if the running stops. If you have to replace the flapper, make sure you get the right kind for your toilet. The majority of toilets use two-inch flappers although three-inch models are becoming more popular for newer toilets.
The flapper isn’t in position.
If your flapper is in perfect condition, the chain looks good, and your toilet continues to run, the flapper placement might be the issue. When the flapper doesn’t properly seal the drain, even the smallest amount of water that slips through can trigger the fill valve to continue refilling the tank. To solve this issue, inspect the inside of your tank when it’s running and see if you can see if the flapper is off-kilter. Sometimes, a simple readjustment is enough to solve the problem. But if the size of the flapper is causing alignment issues, you might have to get a better-fitting replacement.
Getting a new toilet? Read about the best toilet brands to make sure you’re getting the optimal model.
The fill height is off.
The float controls the water level in a toilet’s tank, preventing it from overflowing or underfilling. When your float is set lower than normal, you’ll see a weak flush. Alternatively, a float that’s set too high will cause water to divert into the overflow tube which will prevent the shut-off valve from working properly. Many tanks mark the fill level on the back inside of the tank. Make sure to do a test flush after adjusting the float height to confirm that the water actually reaches your desired level. If you’re not seeing the fill level mark or you don’t want to mess with it, call a professional to get the problem solved. You don’t want to risk an overflow as cleaning your toilet and bathroom can eat up a lot of time.
Is your toilet on the fritz? Whether you need an emergency repair, routine maintenance, or an entire replacement, the experts at Boston Standard Plumbing can help! We’ve proudly served Boston homeowners for years. Contact us today to schedule a booking.


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