I've always used running water to clean bikes and motorcycles, however there is an important point to make... Don't squirt the water directly at the crank bearing or wheel hubs. Never use a pressure washer, and don't even use a squirty-nozzle that pressurizes the water stream in any way. Don't even use your thumb over the tip of the hose to make a stiffer stream. The best is if you have a mister/showerhead style nozzle designed for softly misting the foliage of delicate garden plants.

A light drizzle of water lightly aimed at the body parts of the bike can work very well at cleaning. Basically seals and grease in hubs and bearings are meant to withstand a reasonable amount of moisture such as rain and water spray. So, keep your hose spray as "rainlike" as possible and you'll usually be ok. This all being said, if bikes are run wet in the rain or washed off often, you should service your bearings and hubs more often.