How to Install a Dual Flush Toilet

A toilet in an orange bathroom.
What You'll Need
Dual flush toilet
Crescent wrench
Putty or utility knife
Shop vac
Plastic sheeting

Installing a dual flush toilet system is an excellent way to save water. This type of toilet provides different options for toilet flushing, each using a different amount of water. Liquid wastes use a smaller amount of water, usually 0.8-gallons. A larger amount of water is used to remove solid waste, usually 1.6-gallons.

Dual flush toilets have become very popular in Europe and Australia. In most cases, they are installed in homes in regions where concerns about water usage are high and municipal governments have placed restrictions on residential water use. Follow these steps to save water by installing a dual flush toilet system.

Step 1 - Measure

Measure the distance from the wall behind the toilet to the center of the bolts which hold the toilet to the floor. Also measure the diameter and shape of the base.

Step 2 - Turn Off Water Supply

Turn off the water supply to the toilet. You can usually do so by turning the water valves behind the toilet. Flush the toilet several times to remove all water. Suction any remaining water with a shop vac.

Step 3 - Get Prepared

Place a runner of plastic from the old toilet to the hall and to the outdoors for when you remove the toilet.

Step 4 - Disconnect the Toilet

Disconnect the toilet's supply hose and disconnect the tank from the bowl.

Step 5 - Remove the Toilet

Usually there is a bolt on each side of the toilet. Unscrew the bolts and remove the old toilet.

Step 6 - Insert Rag in Floor Drain

To stop and trap any gas that might escape from the drainpipe, put a rag in the floor drain. Clean away any old wax with a utility knife or putty knife. Following the manufacturer instructions, install the wax seal or gasket of the new toilet. In most cases, hardware and fittings are included when you purchase a dual flush toilet.

Step 7 - Install Adapter

Install the offset collar/adapter of the new toilet to the closet flange. It is the fitting that connects to the drain line.

Step 8 - Install the Toilet

Set the toilet in place. Attach any necessary bolts. Install the rubber gasket on the outlet of the new water tank and insert the screws and rubber washers. Attach the tank to the bowl by sliding the screws through the holes in the back of the bowl. Add and tighten the nuts.

Step 9 - Connect Water Supply

Connect the water supply hose. If desired, use the new water supply hose that is included in the toilet installation kit.

Step 10 - Level the Toilet

Use a level to determine if the toilet rests properly on the floor. If not, add shims under the bottom rim of the toilet until it is level. It may be necessary to use two shims for balance.

Step 11 - Seal and Complete

Apply a silicon seal around the base of the toilet. Reconnect the water line and install the toilet seat.