To remove the old flapper, shut off the water to the toilet using the shutoff valve below the tank. Flush the toilet to empty the tank as much as possible. With the water supply shut off, it won't refill after you flush it. Taking a picture of the inner workings makes it easier to...
Then, flush the toilet and hold down the handle until all the water drains out. That way, you can work unobstructed without getting wet.[2] Watch the flapper as you flush the toilet. A functioning flapper will raise and lower smoothly and settle back over the flush valve without creating...