Common lengths of agricultural water belts, or layflat hoses, can vary depending on the specific application and requirements. However, some commonly available lengths for agricultural water belts range from 50 feet (15 meters) to 300 feet (90 meters) or more.

The length of the water belt is determined by factors such as the size of the irrigated area, the distance between water sources and the crops, and the layout of the irrigation system. It is important to consider the required reach and coverage when selecting the appropriate length of the water belt.

It's worth noting that agricultural water belts can be customized to specific lengths, and manufacturers often offer a range of options to suit different needs. Therefore, it is recommended to consult with local agricultural equipment suppliers or manufacturers to determine the commonly used lengths for agricultural water belts in your specific area and for your particular irrigation setup.