Most use no water and require no sewer hookup, septic system, or plumbing. They're becoming popular alternatives in parks, rest areas, and some homes. Composting toilets can reduce indoor water use by 20 to 30 percent, and also provide a small amount of high-quality fertilizer. Rainwater collection systems, once common in the United States, can supply a significant amount of water for landscape watering and other household needs, even in dry regions. In some parts of the world, such as Bermuda and parts of Australia, homes depend on rainwater catchment systems for all of their water supplies, including potable water needs.
Most systems rely on rooftops to collect rain, which is then stored in barrels or cisterns.
Manufactured components and systems for all three of these technologies are available. For most people, manufactured systems will be the easiest to install and most aesthetic. Keep in mind that these technologies do require some maintenance. Many local regulators are unfamiliar with these technologies, and many states have not defined in law or regulatory guidelines what constitutes an acceptable system. You may have to research available systems and the codes and procedures of various governments to make an effective case to your local officials.