Slow Toilet Flush Leaves Homeowner Stymied

Home RepairLisa asks, “My toilet has a very slow flush. It doesn’t give you a complete flush when you need it to. Is there anything I can do to head off any trouble in the future?”

It could be a number of different things. Let’s go through them.

You should start by removing the tank cover so you can observe the action of the flush valve. When you let go of the handle does the flapper stay open long enough to allow all the water to drain from the tank? If the flush ball or flapper is closing too fast, replace it. Then make sure the pull chain is the right length for the ball or flapper to close. If it is too long the valve won’t open far enough and stay open long enough to allow all the water to leave the tank.

Next, check the rim of the bowl or jet channel to make sure they are not clogged. As you flush the toilet use a small hand mirror to examine the rim holes to see how much water can enter the bowl through the holes. These can get clogged with mineral deposits from hard water. The rim can also get clogged with debris from the inside the tank that has gotten into the rim channel. If you find grayish mineral deposits, you will need to try to dissolve them. First remove as much water as possible from the bowl. The best way to do this is to dump a bucket of cold water into the bowl all at one time which will leave you with a small amount of water in the bottom of the bowl that you will have absorb with a sponge or towel. Next, thoroughly drying the bowl and rim, then cover the jet hole in the bottom of the bowl and all the rim holes with a heavy duct tape. Finally pour white vinegar into the overflow pipe in the tank. This should soften the mineral deposits so you can scrape or clean the deposits.

Another reason for the slow flush could be that there is not enough water entering the bowl. Check to see whether the water level in the tank is as high as it should be. There is usually a mark on the back wall of a tank to indicate where the water level should be maintained. To raise the water level, bend the float ball arm “”up”” or adjust the clip on the refill valve cup. With a slow or lazy flushing toilet you want the water level to be as high as possible without it reaching the top of the overflow pipe.

One of the more obvious reasons for a slow flushing toilet is some kind of object or obstruction in the toilet bowl. Use a plunger to dislodge anything that may be clogging the passageway of the bowl. Sometimes you really have to work at it to remove difficult objects. Push the plunger forcefully down and then quickly pull it back. If this doesn’t work, try a toilet auger. If there is something such as a toothbrush or comb lodged in the bowl passageway, and you can’t dislodge it in this manner, the toilet will have to be lifted from the floor.

When you have the toilet lifted to examine the underside, check in the drain line under the toilet for the object that may be lodged. The drain under a toilet is usually 3 to 4 inches in diameter and requires a large “”electrically”” powered snake. This typically needs to be done by a professional.

The culprit could also be the airflow. There is a vent stack, which allows air to come in to allow the toilet to flush. If this gets clogged the toilet will not flush properly.

While some states mandated the 1.6 gallon toilet standard some years ago, in 1995 the National Energy Policy Act went into effect and mandated 1.6 gallon per flush toilets for the entire United States. Since that conversion there have been many complaints about slow or lazy flush problems. Most manufacturers have it figured out now though. The toilets today, as long as there are none of the above problems, flush much better than they used to.


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