Is it Legal?
There is a lot of false information about water harvesting and some misconceptions. Water harvesting is not federally regulated but in some areas there is regulation at the state and local level. The short answer is that water harvesting is in fact perfectly legal in most areas to include Arizona. It is in fact encouraged in some areas with rebates offered for participation. For additional information:
What does it take?
Is it Worth it?
There are a variety of uses for harvested rainwater. In the southwest, particularly in Arizona there is limited rainfall so it is a tremendous resource. It is most often used for agriculture, neighborhood gardens, landscaping, and emergency use. However, it can be filtered for potable use as well. We often hear that "it doesn't rain enough to collect rainwater". That is precisely why rainwater harvesting is so valuable in our arid climate. While there is limited rain in terms of annual volume it is a great place to collect due to the volume that comes with each rain. That water then can be used into the dry season when all other sign of rain is gone. You can determine a fairly precise idea of potential collection based on your location:
Catchment area: This generally consists of a residential or commercial roof. We have also used roofs from sheds, barns, chicken coops, and catchment areas designed specifically for catching water.
Collection Conveyance:This consists of the gutters, leaderheads, downspouts, and pipe conveyance to take the water to the storage / containment area.
Storage / Containment:This is the area where the water ultimately is sent for later usage. This general consists of either above or below grade tanks or cisterns. Water tanks can be made of stainless steel, galvanized steal, poly-ethaline, or in some cases even lined wood barrels. Several considerations are cost, aesthetics, ease of installation, and the ability to limit air and light.
Filtration:Filtration should begin prior to the water entering into the system and often the best pre-filtration is the use of gutter guards. This keeps the large particulates such as leaves, branches, some pine needles, and some bird droppings from entering the system. Most tanks also come with screens that can be accessed and cleaned out between rains. Additional filtration can occur in a first flush system that takes the initial catchment run-off and sends it into a containment area that when full will allow the cleaner water to enter the system. Additional filtration can consist of mechanical filters, sand filters, and in the case of making it potable ultra-violet light or ozone. In most cases filtration only needs to guard against clogging pumps or outlets for irrigation on non-potable systems.
Distribution: The rainwater can be distributed through a spigot in the tank directly to the destination with gravity. Pumps, either in the tank or outside of the tank, can be utilized to send the water to its destination whether it be landscaping, gardens, or the home.
A rainwater collection system can be extremely simple or it can have some complexity based on your needs. This section will give a general description of the necessary and optional components for a system. One organization that is perhaps the most comprehensive resource, with a tremendous international and domestic knowledge base is ARCSA. This organization can provide great insight at:
Once you learn how much rain you get in your location it is important to then determine your catchment potential. This is the basis for learning whether an investment in a rain harvesting system might be prudent for your needs. There is a simple formula to determine what your collection potential is: