- Decades ago, toilets used 7 gallons of water to flush. Then, it dwindled to 5 gallons and then down to 3.5 gallons. In the mid-1990s, the Department of Energy mandated that all new toilets should adhere to a 1.6-gallon flushing limit. To anyone over the age of 20, it's not your imagination. Toilets did flush better. Your slow-flushing toilet might be functioning to the very best of its ability but design limitations restrict it from working like most people expect that it should.
- Mandated design defects notwithstanding, there are other reasons a toilet might flush slowly, one of which is that water is not flowing from the tank into the bowl fast enough. To have a prayer of working right, as much water as possible must get into the bowl as fast as possible. First, check to see that the water is filling the tank all the way up to the marked line. If it's not, adjustments can be made to the float arm to allow a higher fill.
- Sometimes a toothbrush, comb or other object gets dropped into the bowl and doesn't make it through the passageway between bowl and drain line. Obviously, a blockage of this sort can keep water from flowing in or out quickly enough. A plunger or toilet auger might help dislodge it. If not, you can shut the water off and separate the toilet from the floor. That vantage point should allow you to locate and remove anything that might be stuck there.
- Obstruction is not limited to the lines within the toilet itself. Proper performance of the entire system relies upon clear pipes, lines and drains at every point in the process. For example, tree roots might grow into the main drain line buried underground in the yard, blocking water from flowing out of the toilet as it should, creating a slow flush. And don't forget about the jets that blast water into the bowl from under the rim. Over time, they can become clogged with calcium deposits and other types of buildup, once again reducing the amount of water that flows into the bowl for each flush.