NASA scientists reported Monday night that the space agency has discovered as much as 1.3 trillion pounds of ice on the moon, a finding that indicates future lunar visitors could have a wealth of water waiting for them.Not having consulted the NASA sources as yet, for the time being I'll take the 1.3T lb as an estimate of the total water on the Moon (not the water on part of the area).
If a pint's a pound, that means the Moon has about 160 billion gallons.
However, 300M Americans use 400 billion gallons daily.
Suppose you cut that down to 20B gal/day by recycling. Then a small lunar nation of 3M people would use 200M gal/day. It would take them little more than two years (~800 days) to exhaust the supply.
We're not ready to colonize the Moon even if travel were affordable. We need to find--or make--more water. (There's plenty of solar power.)
However, when technological progres is allowed for, a lunar/Mars-colony test bed, populated by 3K+ high-skilled people supported by robotics etc, does not seem out of the question by midcentury.