Well, let's see how many "shots" this gets... ;-)

Depending on how your unit was winterized it will need to be
de-winterized. If you used non-toxic RV antifreeze (and I
hope you did!) you need to run fresh water through the
entire system until all traces of antifreeze are gone. To
remove it from the 12-volt water pump add water to the fresh
water-holding tank, turn the pump on and open all water
faucets. When the antifreeze is out of the system turn the
pump off and take the water heater out of the by-pass mode
(if applicable). Re-install any water filter cartridges you
removed for storage.

Then I like to sanitize the water system. Make sure all of
the drains are closed and drain plugs are installed. Take a
quarter cup of regular household bleach for every fifteen
gallons of water your fresh water tank holds. Mix the bleach
with water into a one-gallon container and pour it into the
fresh water holding tank. Fill the fresh water holding tank
completely full of water. Turn the water pump on and open
all faucets, run water until you smell the bleach. Close the
faucets and let it sit for at least twelve hours. Drain all
of the water and re-fill the tank with fresh water. Turn the
pump on and open all faucets until you no longer smell
bleach. It may be necessary to repeat this process to
eliminate all signs of the bleach.

While you're waiting for it to disinfect, the system will be
 under preasure.  Inspect everything for leaks, inside and
out. Don't forget to run and check the toilet too.

Someone wrote:

If the system is winterized correctly and then "unwinterized"
properly, there will be no detectable taste/odor/flavor. See below

The most common causes of taste complaints arise from incomplete or
wrong-sequence flushing, though a few fail to bypass the water heater.

Using air to winterize avoids the problem but has serious risks and
simply won't work if residues of water are trapped.

To winterize *most* rigs the right way:

DRAIN water tank & water heater

BYBASS water heater

CONNECT pump inlet via hose to jug of pink stuff (use tee/valve)

PUMP AF into pipes 'til it comes outa faucets (and shower, toilet)

DUMP holding tanks

For more detailed, illustrated winterizing information see
Les Doll's Painless Winterizing, at The RVer's Corner,
<http://www.rverscorner.com/articles/painless.html>.

In very mild climates you can get away without winterizing at all.
Some get by using compressed air, a few by just draining.   But
if you want to be fairly sure of NEVER having to fix split plumbing
parts, the above system is as easy and foolproof as we know about.

NOTE:  Crucial to this question---- When "un-winterizing", flush the
pipes with water BEFORE placing WH bypass valves back to normal.

Will Sill
The self-appointed Curmudgeon of Sill Hill

I always drain the low points.  I do this during the winterizing process to
recover the anti freeze.  I figure that it has done it job of removing the
water from the lines and is no longer needed.  When dewinterizing, I open
them up again just to be sure some more has not sloshed its way down there.

I am wondering about the city water line though.  I would have expected the
shuttle valve to prevent back flow into that line, but maybe not.  It would
not be much to hook the hose up to that and give it a blast while watering.

Man, you've got my vote! If you ever need help opening it up
in the spring, give a yell! :D

--
Steve