Adjust a Toilet Weak Flush

Check the following if your toilet has a weak flush, makes a gurgling sound after or during the flush, or clogs due to a weak flush.

Tank water level height: Make sure the water level in the toilet tank is at the correct level. Check the water line on the flush valve or on the inside back wall of the tank.
Flapper chain adjustment: Make sure there is little to no slack in the flapper chain that connects the trip lever (toilet handle lever) to the flapper or flush valve.
Bowl water level: If the water level in the bowl is low, the toilet will require additional flushes. Review the specification sheet for the toilet for the proper water level measurement.
Clog in waste pipe: If the water or waste backs up when in the bowl when the toilet is flushed, it may need to be snaked or augured. Residential toilet snakes can be purchased at local hardware stores, plumbing retailers, or distributors.
Vent pipes: Make sure the home vent pipes are not blocked or clogged. A blocked vent pipe will prevent air from flowing through the vent. Air flow is critical in assisting in the correct waste flow.
Rim feed hose connection: Make sure the rim feed hose is connected into the overflow on the flush valve. Most toilets have a rim feed hose that supplies water to the rim holes and is attached to the fill valve. It should point downward and be connected inside of the flush valve overflow tube.