Limited water after early August, none in dry years.
Just off of Hwy 21 about 23 miles outside of Idaho City is the Banner Ridge Trail. This is a well-maintained trail that can be traveled by beginners and families. Park at the apron across from the outhouse on Idaho Hwy 21 and start pedaling uphill. Head towards the Banner Ridge Yurt (available for nightly rentals). Just before the yurt you'll see an old logging road break off to the right. Follow this road, there are posted maps along the trail and even limited cell phone service in case of emergencies. Bridges were thoughtfully added at some of the seasonal creek crossings and young aspens beckon visitors in the fall. This trail can be done as an out-and-back.
There are many other scenic Forest Service roads outside of Idaho City that welcome mountain bikers of all levels and give access to many unmarked trails through the surrounding Ponderosa forest. Enjoy!