Attracting Hummingbirds with Water
Virtually all birds bathe in water (although some like dust!), but hummingbirds are especially needful: sticky flower nectar left on feathers makes them impossible to preen and can even cause them to fall out. Providing appropriate water resources for bathing is an important element of attracting hummingbirds.
Hummingbirds prefer to bathe in water that is shallow and moving. This can be provided most easily by having a shallow birdbath that is allowed to gently overflow on one side (easy to do by simply assuring the birdbath is not perfectly level). Having a catch basin below it will facilitate recirculation of the water if desired or needed. This will attract other birds as well as hummers, but this should not be a problem. See in videos here, here, and here.
Other creative ways of supplying the water are possible as seen in the videos here and here.
Fountains with an upward spray are popular in the American West. These are often multi-tiered, providing shallow pools of moving water, but it is the spray from the topmost piece that is important, as hummers will fly up and gently edge into and out of the moving water droplets, as illustrated in this video.
Another technique is to provide a fine water spray/mist, such as is provided by a Leaf-Mister®. These devices use so little water that normally no recirculation is required. A common technique is to mount it 10 feet above the ground and allowing it to spray out horizontally on branches below. Hummers will often sit for extended periods in such spray.
Caution: bird baths, misters, and feeders should be at least 4 feet above a cleared area, so that the hummers cannot be captured by cats.