By GLP Editor Melody Stanford
At a frightening rate, the fundamental ingredient for life – water – is becoming a global scarcity.
Due in part to poor planning and development, soil depletion, strained water tables and groundwater contamination, shortages of usable water have begun to plague historically water-abundant areas. As a result, increasing numbers of people are turning to the rain for help.
In some US states like New Mexico, Arizona and Texas, rainwater harvesting is mandated or incentivized on a municipal level. In the past, states that have relied heavily on rainwater harvesting were those in which water was rare and expensive, creating a void for collecting any water available. Today, however, residents of even water-rich areas are identifying a need for this ancient practice.
Rainwater has been collected and stored for thousands of years as one of the purest sources of water on earth. Indeed, until it hits an object, it is as potable (ingestible) as any filtered source. Once it comes into contact with the ground or a container it becomes somewhat contaminated but is still fit for many uses. It can be stored indefinitely for non-potable means including bathing and washing, flushing toilets (mandatory in Australia), and widely for irrigation. If filtered, it is fit for consumption.
Rainwater is an incredible, free resource that many cultures relay heavily upon to sustain life.
Average water bills in the US can range from $50 to $200. Because an inch of rainfall on a 1000 square foot roof produces over 620 gallons of water, saving and using this water can greatly reduce costs. Most rainwater harvesting systems are so cost-effective that they pay for themselves in less than a year. Such systems are also improvements to property that can increase value.
Besides cost savings, rainwater harvesting is wonderful for the environment. Pumping water to homes from a municipal system consumes massive amounts of energy. The less demand for municipal water, the more resources saved, as well as drought likelihood reduced.
Furthermore, because rainwater harvesting puts water back into the soil gradually over time there is less topsoil runoff, which reduces storm drain contamination and keeps soil healthy.
This same, slow release recharges groundwater more efficiently, which promotes the health of local wells, streams and foliage, and ultimately helps to maintain the municipal source as a whole. For these reasons, harvesting rainwater has a “trickle down” effect for an entire community.
Another vital factor every property owner should consider is foundation safety. Diverting water away from the foundation of a building helps to control moisture, rot, pests and mold. Most home gutters empty directly near the side of the house, which can be a dangerous threat to the longevity of the structure. The preventative nature of this practice alone is desirable to many homeowners.
Rainwater harvesting can be as simple as using rain barrels (appx. 50-300 gallons) under gutter downspouts. However, many people find that they could use more water than a barrel can collect.
A well-designed rainwater harvesting system consists of the following:
- A network of gutters all connected to a central downspout
- A leaf and insect screen that is fed by the downspout
- A first flush diverter that separates the initial dirty roof runoff from the cleaner, more useful water
- A water tank. HDPE high-grade polyethylene tanks are most popular because of the low cost, ease of repair, and durability. Since rainwater can be stored indefinitely for non-potable use, it is best to get a dark colored/UV inhibited tank to reduce algae growth. Above ground tanks are less expensive than below-ground cisterns, though the trade-off of paying for excavation is a more aesthetically-pleasing system
- 1-2 outflow use points, which can be a spigot with hose threads and/or an irrigation line. If the irrigation is a drip system, it is best to install a valve so that drip can be applied during dry weather. If a pump is used, water from the tank can be connected to a sprinkler system. a filter can be attached to an outflow point for potable water. Because of this ease of use and accessibility, rainwater harvesting is very popular with avid gardeners, nurseries and landscapers.
- An overflow point is the final key element necessary to relieve pressure on the tank in the event of heavy rainfall. Most residential-sized tanks will fill up quickly in only a few inches of rain.
Warning: Before considering one of these systems for your home, consult your local and state regulations for legality and permit requirements.
For additional information about rainwater harvesting, visit www.harvestingrainwater.com and check out water guru Brad Lancaster’s book “Rainwater Harvesting for Drylands and Beyond” Vols. I and II.
