While we had the trenches open for electricity, we also put in water lines. Now, next to each subpanel there is a "frost-free yard hydrant." It looks like this:
The drain rock catches lost water without it making a mess. You can set a bucket on the rock, or hang the bucket from the hydrant.
When you turn off the water, a valve at the bottom opens and drains the vertical pipe underground. This prevents damage from freezing in the winter.
Underground, the water pipe is connected to the hydrant with brass fittings. Apparently many installers use plastic fittings, which snap when you attach a hose and tug. Also, a metal fence post reinforces the hydrant.