There are a great many ways of preserving one of the basic units of life-water. One can utilize many methods. From water harvesting to aerators and low flow shower heads and toilets, anyone can make a small change to reduce costs or entirely free oneself of "the grid".

Water harvesting is a primary focus when realizing the possibilities. Since the direct source of water is either of the sky or an underground source, it is only natural to tap into this necessity.

Every piece of real estate has a certain limitless area of ground rights and air rights. A water harvesting system may be achieved to capture rain water and/or snow melt for purpose of filtration. Material-specific roofing must be employed or a proper filtration system. Although it is possible to setup a small inexpensive form of a mini "system" as an experiment. Aquifers, and springs can be tapped into as well with a pump or, well, a well. This God-given compound can be moved to store in resevoirs, then it can later be used for running/drinking water.

Another aspect to recognize is recycling the H2O. This is especially important in arid climates. There are two types of waste water, greywater and blackwater, which present a great opportunity for reformation. Greywater is anything apart from human waste-water drained down sinks etc. Blackwater is anything normally flushed down the toilet. Currently most municipals have a sewer system which allows both types to combine and be disposed of. There are septic tanks too which treat themselves for the most part with already existing bacteria. Greywater and Blackwater may be separated to eliminate the mass volume which has to be maintained.

When we cleanse our bodies in the shower or tub, our bodies release oils and other proteins. Along which this organic matter, foodstuffs via the kitchen sink provide similar nutrients all of which plants thrive on. This one of the beauties of greywater. It would be feasible to recycle this using houseplants and other types of gardening. The actual soil and roots would serve as a primary layer in a filtration system. It would be interesting to test the NH4 (ammonia) containing urine in plants too-this is part of the blackwater scheme.

Blackwater by itself is a minimal volume apart from greywater. This can be ran through a miniature dehydration system that bakes the organic waste in the sun actuating compost for outdoor plants.

Low flow toilets use a fraction of water as opposed to older systems.  Low flow shower heads save on utility costs as does using a water heater containing only the volume your family/household actually uses.  Even regulating water pressure by hand can cut costs.

There are many ways to preserve and conserve on water.  Perhaps starting with a basic alteration allows the best route to begin with.  A 5 dollar plastic barrel, capturing rainwater/snowmelt with a shortened gutter spout, and using 5 gallon bucket to flush the toilet is one way to do it.