This is a concept for a deluxe campshower I have. This was going to be for the Civic Guard (an SCA group - http://www.sca.org). Unfortunately no one had the cash to pitch in for its components.

http://www.robotgroup.net/mark/campshower.gif

Some calculations for it are below:

||ASSUME: 15 persons
ASSUME: 10 minute showers
ASSUME: 12V battery
ASSUME: 200 Amp-hour battery
ASSUME: 50 gallon water tank
ASSUME: 2.5 gal/min pump
ASSUME: person uses 5 gal water per shower

total shower length per day = 10x15 = 150 minutes per day

How long a fully charged battery will last:
200/5.5 = 36.36 hours continuous usage
36.36hr x 60min/hr = 2181.81 minutes
2181.81min / 150min/day = 14.54 days @ 150 minutes per day

How long a full water tank lasts:
(under continuous usage)
50gal / 2.5gpm = 20 minutes continuous
(under intermittant usage)
50gal / 5gpp = 10 people can shower before tank is dry
NOTE: this assumes that the showerer will only have the water
on long enough to get wet or to rinse. No water usage during
lathering, scrubbing, or shaving. Also, no account is made
for the hot water reserve. I reccomend that we have two water
barrels so that one may be filled while another is used.

Another note:
It gets cold at Gulf War. Pipes may freeze. How do we prevent that?
We could bury the hoses but will that work? Draining is not
practical. Also, we could use some sort of insulation on the
uprights.||