What determines the flushing efficiency of a toilet?

The flushing efficiency of a toilet is significantly influenced by the size of the tank opening. A larger tank opening can facilitate better water flow and reduce blockages, allowing the toilet to flush waste more effectively. This is crucial because the design of the opening can impact how quickly and forcefully water enters the bowl, which is essential for the overall flushing performance.

While the other factors mentioned, such as the type of water source or the amount of water used per flush, can play a role in water conservation or the effectiveness of the flushing action, they do not directly address the mechanics of how the toilet performs its flushing function. The color and design of the toilet are primarily aesthetic and do not impact its functional efficiency in flushing waste.