The toilet flapper may not stay up due to a worn-out or misaligned flapper, a problem with the chain or handle, or issues with the water pressure or tank level.
The toilet flapper stays up to allow water to flow from the tank into the bowl when the toilet is flushed.
My behind
A flapper on a toilet is a rubber or plastic seal that covers the opening at the bottom of the toilet tank. When the toilet is flushed, the flapper lifts up to allow water to flow from the tank into the bowl, causing the toilet to flush. After the flush is complete, the flapper falls back down to seal the opening and prevent water from leaking out of the tank.
A flapper valve toilet works by using a rubber flapper to control the flow of water from the tank into the bowl. When the toilet is flushed, the flapper lifts up, allowing water to rush into the bowl. Once the tank is empty, the flapper closes, stopping the flow of water and refilling the tank for the next flush.
The toilet flapper may not close properly due to wear and tear, misalignment, or a build-up of debris preventing it from sealing tightly.
The purpose of a rubber flapper in a toilet is to seal the opening at the bottom of the tank and prevent water from leaking out. When the toilet is flushed, the flapper lifts up, allowing water to flow from the tank into the bowl, creating the flushing action.
Make sure the toilet is the source of the leak. Put dye in the tank and see if it shows up in the bowl or shut the supply off to the toilet and see if the tank level goes down. You replaced the parts inside the toilet but did you check the surface where the flapper seals against the drain? This can be pitted or have rust built up on it. Is the chain to the flapper the right length? Too short and holding the flapper up or too long and getting under the flapper.
check that the toilet stopper has been switched on and check that the strainer inside the toilet inlet is clear of debris
The flush valve (flapper) is leaking slightly, lowering the water level in the tank. To see if the flapper is leaking, put some food coloring in the tank and see if the color shows up in the bowl. This means the flapper is leaking by. Do not flush toilet for a while to see if the food coloring shows up in the bowl
Your toilet may keep filling up due to a faulty flapper valve or a problem with the fill valve. To fix it, you can try adjusting the water level in the tank, checking and replacing the flapper valve, or adjusting the fill valve. If these steps don't work, you may need to call a plumber to diagnose and fix the issue.
That is the 'flapper valve' in the bottom of most toilet tanks. This valve is pulled up when you flush, admitting water into the bowl.
Your toilet may fill up when flushed and drain slowly due to a clog in the pipes, a malfunctioning flapper or fill valve, or a problem with the sewer line. It is important to address this issue promptly to prevent further damage and ensure proper functioning of your toilet.