Upgrading to a Dual Flush Toilet

How Dual Flush Works

Dual flush toilets provide two flushing options: a half flush (typically 0.8 to 1.1 gallons) for liquid waste and a full flush (1.28 to 1.6 gallons) for solid waste. Compared to older toilets that use 3.5 to 7 gallons per flush, dual flush technology can reduce water consumption by 25 to 67 percent. The average household flushes about 20 times per day, so the water savings add up quickly — often 10,000 to 20,000 gallons per year for a family of four.

Conversion Kits

If you want dual flush capability without replacing your entire toilet, conversion kits are available for most standard toilets. These kits replace your existing flush handle and flapper with a dual flush valve system. Installation takes about 15 minutes — shut off the water, drain the tank, remove the old flush valve hardware, and install the new dual flush valve and buttons following the kit instructions. The button replaces your flush handle and provides two push options. These kits cost $20 to $40 and are compatible with most 2-inch flush valves.

Choosing a New Dual Flush Toilet

When purchasing a new dual flush toilet, look for the WaterSense label, which certifies the toilet meets EPA water efficiency and performance standards. Check the MaP (Maximum Performance) rating — a score of 600 or higher means the toilet handles solid waste effectively. Consider the rough-in measurement (distance from the wall to the center of the closet bolts — usually 12 inches). One-piece toilets are easier to clean but heavier to install; two-piece toilets are more common and easier to maneuver into position.

Installation Tips

Installing a new toilet follows the same basic process as any toilet installation. Remove the old toilet, clean the flange, install a new wax ring, and set the new toilet. Most dual flush toilets use a different internal valve system than standard flappers — follow the manufacturer's specific instructions for the flush valve and button assembly. After installation, test both flush options multiple times and adjust the water level to the manufacturer's recommended fill line. Inform all household members about the two-button system to maximize water savings.