What is the Key to Having a Safe Source of Water From Your Rainwater Collection System?

This is Part 8 in the series.  Click to see parts onetwothreefour, fivesix and seven of “How to Build a Rainwater Collection System”.

What is the Key to Having a Safe Source of Water From Your Rainwater Collection System?Whether potable (drinking water) or non potable (irrigation, toilet, laundry), filtration and disinfection are key to having a clean and safe source of water from your rainwater collection system.  Of course, pre-screening the rainwater before it enters the storage tank is essential as discussed in part 3 of this series. Filtration for a non potable irrigation system consists of a sediment filter after the pressure pump.

A 5 micron poly sediment cartridge filter will keep particles from clogging your soaker hoses and emitters. Cartridge filters come in various sizes. Smaller 2″x 8″ filters will need to be changed more often. Whereas larger cartridge filters, if not used regularly can hold bacteria and develop a bad odor. Generally for average irrigation needs, a  4″ x  10″  5 micron poly sediment cartridge filter will do the job. Be sure to remove and discard  the cartridge after the watering season so filter does not go sour during the non-use months.

What is the Key to Having a Safe Source of Water From Your Rainwater Collection System2For non potable, toilet flushing and laundry facility systems, it is recommended to add a 10 Micron carbon filter. This filter will remove organics and inorganics, color and odor from you stored rainwater. By having the cheaper 5 micron sediment filter upstream of the more expensive 10 micron carbon filter you will save money by not fouling the carbon filter with particulate less than 5 Microns. Depending on how much use for this type of system, a  4″ x  20″  cartridge will mean less changing of filtration. If the system is to be shut down for a lengthy period, it is recommended that filter cartridges be removed so water will not become septic by decaying bacteria.

Lastly if a potable system is desired, a 1 micron absolute filter that is certified NSF 61 for cyst removal is recommended downstream from the sediment and carbon filter. A 1 micron absolute sediment filter will remove cysts but is not intended to be the final disinfection for potable water. Again, a  4″ x  20″ cartridge will mean less change outs of the filter. A 1 micron absolute filter is intended to be used in addition to UV sterilization. With the UV to be the final element in the treatment system. We will discuss UV disinfection in part 9 of  this series (check the box below to receive new posts via email).

Regular inspection and maintenance of your filtration system will insure safe, and proper operation of your potable and non potable rainwater catchment system.

Ken Blair
A rainwater collection systems designer and consultant, Ken has designed and installed residential and commercial systems, primarily in the northwest United States for more than 10 years and, in 2014, began consulting and managing builds in other states. Ken is an accredited ARCSA Professional Designer / Installer and Life Member, the Northwest Regional ARCSA representative and advisor to its education committee and is available to speak about Rainwater Collection Systems design and builds.

Ken is a United States Navy veteran, having served on active duty during the Vietnam War era. He attained the rate of E-4 Machinist Mate.

A career entrepreneur, Ken created a new business focus with a commercial dive company in Hawaii in the mid 1980′s to respond to and clean up oil spills, oil spill equipment training, service and maintenance for the oil co-op service industry. Ken is passionate about having a positive impact on the environment and is also a founding director of BANK-ON-RAIN (2011-2014), whose mission is to create grassroots solutions for rainwater collection for consumption and agriculture in developing areas of the planet.

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