If your toilet has two buttons on top of the tank, they are not simply a modern design feature. They are designed to control how much water is used with each flush. The smaller button releases less water and is usually meant for liquid waste, while the larger button releases more water for solid waste. Depending on the model, a smaller flush may use around 3 to 4.5 liters, while a larger one may use about 6 to 9 liters. The basic idea is simple: “use only as much water as necessary.”

This small choice can make a significant difference over time. A toilet may be flushed many times each day, so avoiding unnecessary full flushes can reduce household water consumption. The original source estimates that a dual-flush toilet can save a household up to 20,000 liters of water per year compared with a traditional toilet. Using less water can also reduce wastewater and potentially lower water bills.

The idea of using different amounts of water for different types of waste was discussed by designer Victor Papanek in his 1976 book *Design for the Real World*. Australia became an early adopter in the 1980s as it looked for ways to conserve water during drought concerns. Since then, dual-flush toilets have become common in homes and public buildings worldwide.

Despite their popularity, many people still do not know which button to use. Designs vary, with symbols including half circles, full circles, and water drops. Some people simply press the larger button every time, which wastes water unnecessarily.

The easiest rule to remember is: “Small button = smaller flush. Large button = larger flush.” In most models, the smaller option is for liquid waste and the larger one for solid waste. Since designs differ, checking the symbols on your particular toilet can help you choose the appropriate flush and avoid wasting water.