Slow flushing toilets are also sometimes known as lazy toilets, lazy flush or phantom flushing toilets. There are several possible causes for a slow flushing toilet. Sometimes, the fix is easy, depending on the cause. You may be able to repair the problem yourself and avoid an expensive repair bill. On the other hand, if the problem is caused by an obstruction to the main sewer drain, you'll likely need to call a plumber.
Examine the inside of the toilet bowl. Just under the rim, you should notice a series of small holes. These holes can become clogged, which means that your toilet will not flush properly. Take a wire coat hanger or similar tool and poke it at the holes to clean the gunk out of them. After you've done that, examine the exit hole at the bottom of the toilet. You should notice a smaller siphon jet hole. Poke the coat hanger around this hole to get rid of any residue.
Flush the toilet several times to see if this has taken care of the problem. If your toilet still flushes slowly, remove the tank lid and locate the flapper–a round piece of rubber. Flush the toilet while observing the flapper. If the flapper drops back down before about 80 percent of the water has left the tank, you'll need to replace the flapper.
Determine whether the flapper seals properly by placing several drops of food dye into the toilet tank. Do this after flushing and after the water stops filling the tank. Wait about 10 minutes, then check the toilet bowl to see if the dye has escaped the tank. If it has, you need to replace the flapper.
Check to see whether you have sufficient water in the tank to flush the toilet properly. Some low-flush toilets were designed to use less water. This may be environmentally-friendly; however, it often doesn't lend itself to proper flushing. If the water level in the tank is low (there should be a mark on the tank wall to indicate water level), adjust the float ball arm upward.
Determine whether a clogged drain is causing your "lazy" toilet. Use a funnel-cup plunger that has a flange (an extra piece of rubber) around the bottom. Get a good seal around the exit hole of the toilet bowl, then plunge forcefully several times.
Use a toilet auger if the plunger does not bring up any clogs. Toilet augers are available at hardware stores. Hold onto the handle and push the cable end into the exit hole. Crank the handle. If the auger stops, it's reached an obstruction. Gently wiggle it back and forth to break up the clog or pull it back up.
Call a plumber if you have found no obstructions in the toilet drain and other measures to fix the toilet have failed. You may have a clog in your main sewer drain. Often, tree roots will obstruct the main line. A plumber can clear this obstruction.