July 14, 2015

The Inherent Value of Rainwater Harvesting

The process of harvesting rainwater is very simple. Water for the home is captured from the sky, filtered, used by the inhabitants, and filtered back clean into the environment for landscape watering purposes.Constructing a building typically disrupts the environment and the beauty of a rainwater harvesting system is that it actually preserves the hydrologic system through the recycling of captured rainwater.

This method is fairly intuitive. The water doesn’t contain the dissolved minerals and salts typically found in the well water you might be using to supplement your outdoor water needs, and it helps preserve California’s already limited water. Rain is a good source of water that would otherwise become polluted runoff picking up chemicals and other dangerous waste as it trickles down streets and gutters on its way to a network of storm drains or the nearest low-lying body of water. This can be quite the problem in Malibu as a majority of the polluted runoff will eventually come to rest in the ocean.

Our team at Armfield Design & Construction has been designing and installing rainwater harvesting systems for over three decades.Our CEO, Mark, saw the benefits early on and had the foresight and heart to create a non-profit centered around the idea: RainCatcher. RainCatcher has saved over a million lives through the gift of clean water. They’ve installed over 100 rainwater harvesting filtration systems throughout Africa and have recently started projects on the Navajo Reservation in Arizona. Our team at Armfield has become experts in rainwater harvesting systems, and we’ve witnessed firsthand the benefits for preserving the environment in Southern California as well as saving millions of lives elsewhere.

Here’s a brief illustration of a typical project:


The process begins at the rooftop where the building harvests rainfall and sends it down through the gutters to a cistern located either above or below ground. These cisterns can hold tens of thousands of gallons of water and have the ability to store enough water for over a year. Despite the current drought in California, one rainstorm will supply enough water for many months depending on the size of the tank and the building’s water needs.


Before any of the harvested water is used, a typical system will have the collected rainwater pass through micron and UV filters, get treated with small amounts of chlorine to ensure that home’s water lines remain bacteria-free, and pass through charcoal filters at the faucets and shower heads to remove the added chlorine. All of the home’s water needs–water for drinking for drinking, dish washing, showering, and “flushing” of composting toilets – is supplied by the harvested rainwater.


Once water is used at the sink or the shower, the resulting water goes down the drain, through a couple filters, and to a holding tank. The water is then pumped and filtered again to nourish the landscape and bioswales.

These systems, ensure that no water from the home enters the sewer. Water is either used on site, returned to the air through the evapotranspiration of plants, or filtered to the groundwater. For the most part, all of this is “out of sight, out of mind” for homeowners and leaves both the homeowners and environment happy.

Stay tuned for a post in a few weeks with information on how to keep your lawn green in the middle of the drought!