Flushing the toilet is a routine gesture we rarely question. Yet, each flush uses 3 to 9 liters of perfectly clean drinking water—just to remove a bit of urine. Multiply that by the number of flushes a day, nd a single household can waste up to 100 liters daily—over 36,000 liters a year. Meanwhile, illions lack access to clean water.

A simple, eco-friendly habit has emerged: “If it’s yellow, let it mellow; if it’s brown, flush it down.” Urine is sterile and poses no health risk if the toilet is cleaned regularly.