System Types Rain Water Harvesting
At the moment, 2 types of systems are generally used. These include DIY and commercial systems. Both of these systems are known under the term water harvesters and require only a limited amount of knowledge to set up (if basic systems are used). In both cases, the system consists of a storage tank to store the water and piping (to guide the water in). Additionally, extra pressuring equipment as pressure vessels, inline pump controllers or pressure sensitive pumps may also be required. Finally, water purifying equipment as water-purifying plants, UV-lights or distillation equipment are sometimes (depending on local conditions) added to purify the collected water. The system is then called a Greywater treatment system. Greywater systems are usually preferred over regular water harvesters as they allow the system to not only treat the rainwater, but water from other sources as well (eg the watercloset; if plants are used). However, this feature may also be averted by using a UV-lamp and composting toilet instead.
Depending on local circumstances, a gravity-fed system may already be enough to have a pressured water collection system. In the latter case, no pumps/pressure vessels are thus required to have a pressured system. In practice, gravity-controlled systems are usually created by placing the water harvester on an elevation (eg rooftops).
DIY domestic systems
As water conservation is becoming more and more popular, more people have begun to make their own homebrew installation. These systems range from traditional technologies like rain barrels to more complex greywater systems. Through the internet, plans and accurate construction information have become available. Depending on the degree of personal skill and preference, a more basic (regular water tank and piping) -or more advanced (e.g. pressured systems with water treatment, etc.) system is chosen.
Commercial domestic systems
Commercial rain harvesters can be obtained in both pressurized as gravity-fed systems.
System's operation
A mechanism can be used to send the initial water flow to waste, usually the first few liters. These are commonly known as first-flush diverters, and are used to increase the chance that the large-particle residue that might accumulate on your collection surface is washed away from (and not into) your storage tank. Such a system also compensates for the fact that the initial minutes of a rainfall can include airborne pollutants being washed from the sky, and likewise minimizes contamination of your captured supply. Simple but regular inspection and maintenance of such a device is usually necessary.