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A leaking toilet, one of the most common plumbing problems to plague homeowners, is known to cause house-wide havoc. Not only is it a nuisance, a leak wastes water, increasing your monthly water bill. But, what if you don’t know that you have a leak? How can you detect a silent leak before it causes widespread damage and expensive toilet repairs

Luckily, there are many ways a homeowner can check to see if they have a toilet leak. Here are some clues to look for that may mean you have a toilet leak, as well as a few easy tests you can do to detect a silent toilet leak.

What Causes a Silent Toilet Leak?

Before finding a solution to the problem, it might help to understand where the problem comes from in the first place.

One possibility is an ineffective flush valve system. A flush valve is the mechanism that allows a toilet to flush by releasing water in and out of the tank. This device is comprised of a trip lever, lift rod, tank-ball, flush valve seat, flapper, and an overflow pipe. The flapper is intended to create a watertight seal, but the rubber can deteriorate overtime. As a result, water can slowly leak from the toilet. 

A second cause of a silent toilet leak is an issue with the fill valve. A flush valve allows water to exit the tank, but a fill valve, in contrast, is the mechanism responsible for water entering and filling up the tank. Sometimes, the fill valve mechanism can come out of place or the shut-off valve might not close properly. This leads to a continuous flow of water into the tank, which then leads to slow and silent leaks.

Why Silent Toilet Leaks Are So Damaging

A toilet leak is both taxing for your wallet and the environment. In fact, a silent toilet leak can cost you hundreds of dollars for what could be a simple fix. A running toilet or leak wastes about 25 times more water than a shower leak and about 4 times as much water than a faucet leak, which contributes to the nearly one trillion gallons of water wasted annually by household leaks. In just one day, a silent toilet leak can result in 300 gallons of wasted water.

In addition to the wasted water, a silent toilet leak can reap lasting damages to your home. When a toilet leaks from the bottom, water could seep into the floors. This can damage the structural integrity beneath the toilet, which might in turn lead to additional hazards in your bathroom.

If your toilet is severely leaking, it could be wasting an extremely large amount of water and costing you. Typically, a leaking toilet will waste thousands of gallons of water per month. This could translate to approximately $200 unnecessarily tacked onto your monthly water bill, which adds up to almost $2,500 a year wasted on a toilet leak.

Moderate leaks will not put such a dent into your wallet, though they will still be costly; even minor leaks can set you back more than $1,000 in waste a year. So, for a lower water bill and better environment, it’s important to spot a toilet leak early on.   

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Ways To Detect Silent Toilet Leaks 

Not only are there a few ways to determine if a silent leak is present, but you can do it all yourself without the help of a plumber. Plus, the sooner you catch a leak, the faster you can fix the problem. Here are a few easy ways to determine if you have a silent toilet leak on your hands. 


The first way to detect a silent toilet leak is by taking a look at the toilet and the area surrounding it. When looking in the toilet, you might notice that water is trickling down the sides instead of filling up to a normal level and staying stagnant. Additionally, there might be moisture around the base of the toilet. 

If you notice either of these indicators, try flushing the toilet. When you need to hold the lever down in order for the toilet to flush completely, there is likely a leak somewhere in the system. 

Dye Test

Homeowners can perform a simple dye test that can be bought from a water or plumbing supply company. These toilet leak detection tablets are either blue or red and are extremely inexpensive, as one package contains two tablets.

The test is simple; all you need to do is place a colored tablet into the toilet tank, wait for a period of 10 minutes, and then check to see if there is any color in the toilet bowl. If color shows up in the bowl, then a leak is present, and you need to contact a plumber

Pencil Test 

You only need a pencil with this other easy test to see if you have a leaking toilet. Take your pencil and draw a line on the back wall of the tank, and on the waterline on the interior of the tank. Shut off the water supply and wait for 30 minutes.

The leak is taking place at the refill valve (located on the left side of the tank) if the water is still at the pencil mark. If the water level drops below the pencil mark, then the toilet leak is a result of the flush valve (located at the center of the tank).

Water Leak Sensor

Homeowners can easily detect a leaking toilet by purchasing a water leak sensor. These sensors will inform you as soon as the toilet begins to leak by flashing a red light and making a beeping sound. If the toilet is correctly working, the sensor will flash a green light. These devices are fairly inexpensive, and can be purchased for approximately $20.

Test the Fill Valve

Fill valve leaks are very difficult to detect. To discover these leaks, first begin with a full toilet tank. Then, remove the covering of the tank and determine if water is flowing in the overflow tube. If water is flowing, a leak is present, and you need to contact a professional plumber for toilet leak repair.

When to Call a Sacramento Plumber For Your Toilet Leak

Hopefully, these toilet leak tests will help you catch that annoying leak so you can save water and money! You’ll have to hire a professional plumber to take care of serious leaks, such as a fill valve leak.  Or, if these tests don’t work but you still suspect you have a leak, then you’ll need to hire a plumber to come check out your toilet.

Whatever problems you may have with your toilet, call the most cost-effective and affordable plumbers in Sacramento, Express Sewer & Drain! We offer a wide array of services, including leak detection, with flat rate pricing so we’ll never charge by the hour. So, don’t waste any more water! Call Express Sewer & Drain today.

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Topics: Pipe Leaks and Repair, Home Plumbing, DIY