One of the key problems with relying on fresh rain water for household use is the difficulty of collecting and storing it. Rooftop collection systems that channel rain water into a storage tank are not always highly efficient. They can also only supply water during moderate or heavy rainfall when there is enough water to collect. This means that supply can vary seasonally or be non-existant during periods of drought. Fresh rain collection also requires installation, maintenance and regular inspections to ensure that it is clean and ready for use whenever rainfall occurs.
A water softener is a device that uses a sodium or potassium filter to deionize the chemicals in hard water. If the water that your public utility provides has high levels of magnesium or calcium, a water softener will remove them and prevent fixture stains, reduce mineral buildup in pipes and purify your drinking water. However, water softeners are complex systems with multiple layers of insulation, multi-stage cycles, and pipes and valves that are subject to failure or blockage.
Even with a fresh rain collection system or water softener in place, you may not get access to the pure, natural water you want. Fresh rain water is subject to the presence of chemicals from the atmosphere, as well as contamination from your rooftop, collection system and storage tanks. A water softener can produce a salty buildup that enters your water supply. It also can't protect against microorganisms in the water.
Both water softeners and fresh rain collection systems bring a substantial added cost to the process of supplying your home with water. A basic rain barrel that your roof's gutters empty into is one low-cost option, but will only supply a limited amount of water for watering a garden or yard. Water softeners can cost upwards of $1,000, with failures and cleaning needs representing ongoing costs. A system that harvests fresh rain water and filters it for household use will be expensive if it's large enough to supply the 50 to 100 gallons of water that a person uses in a typical day.