How to Fix a Slow Flushing Toilet

The easiest fix for a toilet that doesn't flush, is to check the flapper chain. Chain length and obstructions are often the most common reasons for a slow-flushing toilet.

If the flapper chain is too loose, the flapper will not lift off the flush valve opening, causing a weak flush. If the flapper chain is too tight, the flapper will not seal, causing your toilet to run. We recommend leaving only 1-2 chain links in slack.

Some flappers are adjustable, and this can cause a slow flushing toilet. Korky flappers have a band or dial that determines how fast the flapper either sinks or floats. For help troubleshooting how to fix this, go to the last step in our guide about how to replace a toilet flapper.

Two sizes for flappers are available: standard 2-inch and large 3-inch. If you have the incorrect flapper for your toilet model, it could lead to incomplete flushing.

Some toilets require specific fit flappers, due to the flush valve design. Try using our Toilet Genius Assistant® to confirm if you have the correct type of toilet flapper for your toilet model.

The refill tube connects your fill valve to the flush valve overflow tube. If it is not connected properly, water will not flow into the bowl. This will cause the bowl to have less water, leading to a slow or weak flush.

The height of a fill valve's float will determine the water level in the tank. If you set the float too low, you will not have enough water in the tank, which will cause a weak flush. If you set your float too high, water will overflow through the overflow tube, causing a running toilet.

Korky fill valves feature an internal float. To control the water level, start by turning the water supply off. 

Next, twist the valve counterclockwise to unlock it and adjust the height. Make sure the bottom of the cap is lined up with the top of the overflow tube. When done, turn the body of the fill valve clockwise to lock it back into place. Then slowly turn your water supply back on.

Over time, your fill valve can start malfunctioning for two reasons. The most common being that the float gets stuck, the other being internal sediment buildup.

Stuck Float Valve

A stuck float valve happens when the fill valve float gets jammed or restricted in its movement. This prevents the valve from opening or closing properly, resulting in the toilet tank either not filling fully or continuously running water. If you have a Korky valve, you can take the cap off and clean the enclosed float to ensure it moves properly.

Internal Debris Build-Up

If you have a Korky fill valve, you can take it apart and service it. We recommend doing this occasionally, as the fill valve can become clogged with mineral deposits or sediment over time. If you do not have a Korky valve, or it is older than 5 years old, it's recommended to replace it with a new valve.

If your flapper and fill valve are working properly, you might have clogs in your toilet's rim jets. The rim jets are the small holes located at the top of the toilet bowl. This is where water flows from when you flush.

When you flush a toilet, water flows in a circular direction around the bowl. If your rim jets start to get clogged, you may notice your flush becoming slower over time. If gone unfixed, your water will eventually not flush around the bowl, but straight down.

To easily unclog your toilet's rim jets, we recommend using in-bowl cleaner and a brush. If the rim jets are still clogged, you might have to gently clean each outlet with a wire. Porcelain can easily chip, so be careful! You should also wear gloves and eye protection to protect from splashing.

If your toilet has a deep clog at the outlet, it can obstruct water from going down the drain at the right rate. You can fix this by plunging your toilet if the clog is made of waste.

If you accidentally drop something into your toilet that shouldn't be there, you may have to shut off the water supply, remove the water, and disconnect your toilet to manually remove the clog. If you have to do this, you will have to get a replacement wax-free gasket to create a new seal from your toilet to the floor.