Farmers in Serenta irrigation scheme in Northern Ethiopia have been using too much water for irrigating their onion crops, leading to water wastage and low productivity. A study was conducted to analyze water use efficiency and irrigation scheduling in the scheme. By measuring water use productivity in different fields, it was found that applying less water than usual can actually lead to higher crop yields. The tail-end users, who used less water, had the best return per unit of water applied. This shows that applying water based on crop needs, rather than just using more water, can improve productivity on onion farms in the area.