While plunging the toilet may cause the bowl to overflow, it had no real connection to the tank overflowing. The way to solve the tank overflow, is to replace the float and other parts inside the tank. The tank will over flow if the float is stuck in the down position and the top of the overflow tube is clogged.
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If the fill valve isn’t working properly, the tank will generally overfill through the overflow tube, and the excess water will continue to run into the toilet bowl. This is usually either caused by a waterlogged float or when the water level is set too high.
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As the water leaks out of the tank and into the bowl, it is then replenished by the fill valve, causing a continuous flow of wasted water. To check for this, first shut off the water supply to the toilet. Mark the water level in the tank with a pencil or marker, then check it again in 10 or 20 minutes.
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Inspect water in bowl to see if there any signs of color from fabric softener or food coloring. If so, the toilet has a leak. Shut off water to toilet. Mark water level in tank with marker or a pencil. Check back after 10 minutes to see if water has fallen below mark.
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What Causes a Toilet Overflow. If you have a septic system and your toilet overflows, the first thing to consider is when you last had the system pumped. A system that has filled beyond capacity can cause backups, ultimately leading to the toilet overflowing.
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The most common cause of a leaking toilet tank is when the flapper fails to seat properly and form a tight seal against the valve seat. This lets water leak from the tank into the bowl. It may be caused by the flapper being out of position.
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In most residential septic systems, all the household wastewater runs from the plumbing pipes into an underground storage tank. Heavier solids stay in the tank and settle at the bottom in a layer known as sludge. Grease and lighter solids form scum on the top layer. Liquids flow from the tank into the drain field.
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Another problem with trees is that their roots can grown into a pipe, causing a blockage. The last item that cause the overflow is blockage from items put into the toilet. My three year old daughter, who is learning how to use a toilet, will overfill it with toilet paper. I have seen diapers, toys, and bundles of dog poop stuffed into a toilet. Not a wise idea.
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Only human waste and toilet paper should be flushed. According to the U.S. Environmental Protection Agency, 25 percent of U.S. homes have a septic system to handle wastewater from the bathroom, kitchen and laundry. If your home has a septic system, proper care and maintenance will prevent an overflowing toilet as well as other septic system headaches.
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The float bulb inside the tank may have sprung a leak, keeping the shut off valve from working. While plunging the toilet may cause the bowl to overflow, it had no real connection to the tank overflowing. The way to solve the tank overflow, is to replace the float and other parts inside the tank. Source(s):
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what causes a toilet bowl tank to overfill?
If the fill valve isn’t working properly, the tank will generally overfill through the overflow tube, and the excess water will continue to run into the toilet bowl. If the fill valve isn’t working properly, the tank will generally overfill through the overflow tube.