- Blocked jet holes. When a toilet flushes, water shoots through small holes. Minerals in the water can build up slowly and lower the pressure of the water going into the bowl. Because of their location, it is difficult to see these holes, so most people forget about them. A simple maintenance tip is to clean the holes occasionally using vinegar.
- Drain blockage. This can affect not just the toilet, but the bathtub and sinks as well. If the drain gets clogged, water leaving the toilet will have nowhere to go. Usually this is caused by buildup of grease, or tree root intrusion, but flushing the wrong material can have the same effect. Monitor young children, and make it clear to them that only toilet paper should be flushed.
- Low water level in tank. The tank must have enough water for a powerful flush to clear the bowl. A problem with the trip assembly is a common cause of low water in the tank. If the toilet has been recently worked on, the fill valves may not have been properly set. Lift the cover and make sure that the water level is close to the top of the drain pipe.
- Flapper valve not working properly. This valve opens at the bottom of the tank to release water into the bowl. In older toilets the valve may be worn, so even when it is closed water leaks out and keeps the tank from filling up. The flapper valve is a cheap item, and it is easy to put in a new one.
A toilet can flush slowly for a number of reasons, but whatever the cause, it can be annoying for the homeowner. A slow toilet does not remove waste effectively, and it could indicate that there is a problem in the sewer system. You should always have a plunger handy, just in case the cause is simple, but in many cases a plumber has to be called. Here are some of the most common reasons for slow toilets.