Come to find out, potable water (the water we can drink) is an expensive resource. With a city water system, there is a lot of processing that goes on to make it drinkable. That is, if there is a source of water to use. Many desert cities, California, Africa, Australia, and other places around the world have a hard time finding enough water. Ocean water is not an option, because it takes a lot of resources to get the salt out. Saving water is good for your local water supply, and it'll reduce your water bill. For those resorts that have a well, reusing water can reduce your electric bill to pump the water.
More types of water exist than just the two I listed at the top of the post.
- Potable water, or whitewater -- safe to drink.
- Rainwater -- usually safe to drink, but is better used for other things.
- Greywater -- water from sinks, showers, washers, can be reused.
- Blackwater -- water from toilets, unusable.
Watering the plants is easy, and should never require potable water. Plants by the washers could receive that water. Plants by the showers could receive that water. Plants by the kitchen sink could receive that water. (The bits of food are good fertilizer.) The only worry is which soaps can be used, as some may damage the plants. Of all three sources, the sink probably has the least amount of soap in it. Plants anywhere else can get water from a simple rain catch and a barrel, or be xeriscaped.
For more serious usage of rainwater, consider a complete rainwater harvesting system for your buildings. In places with lots of rainfall (or a big roof), collecting it would reduce your water bill to almost nothing. With moderate rainfall, you would only pull water from the city system when you've run out of rain.
To calculate how much rain you can collect from a building, you need the size of the building and annual rainfall amount. With a typical single-wide mobile home of 18 ft. by 90 ft., and a rough average of 3 inches of rain per month during the Wisconsin summer, at 85% recovery, this calculator says we can get over 2,500 gallons of water each month. With alow-flow showerhead (a very wise choice to save water) running at 1.3 gpm, the rain would supply 33 hours worth of showering, or 396 five-minute showers. Remember though, this is just from a mobile home and only 3 inches of rain per month. Bigger roofs and/or more rain would make this number a lot bigger!
Another place to conserve water, if applicable, is the toilets. No-flush urinals and dual-flush toilets save a lot of water! The urinals supposedly save 40,000 gallons per year, and the toilets save 67% of the water they would normally use. If you don't have an abundant supply of greywater, these solutions would be ideal. For more information on water reuse, here's another good resource and a smaller guide.
For my rural hilltop resort, I probably won't be connected to the city water supply. There may be added cost with pumping water from a well up to that height, so conserving water would reduce the electric bill. Rainwater will certainly be collected, greywater will be reused in the toilets and for the plants, low-flow showerheads, no-flush urinals, and dual-flush toilets will all be installed. For the number of years that the water system will last, it may or may not be cost effective depending on the cost of the rainwater collection system. (The rest is fairly cheap.) It has to be close though, so it's worth doing even if it's just for bragging rights.