Water resources are in tremendous demand in the arid Sahel, including Mali's Dogon Country. Decreasing rainfall and desertification make water rarer and more valued every decade. Most villagers draw water by hand from deep wells for drinking and household use. The depth of the water can vary from 1 to 25 meters, depending on the location, the time of year, and the amount of rainfall received that year. During the brief rainy season, from June to August, the water table rises, and then it falls during the rest of the year. In highland Ecuador, water is much more available, and priorities focus on delivering it to homes, purifying it, and protecting watersheds by planting trees. Tandana assists in improving water access and quality with materials, volunteer labor, and training.