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Rainwater Filtration and Rainwater Purification

 This page describes the rainwater purification systems I sell.


rainwater purification, purifying rainwater, rainwater filter

Kitchen Defender for rainwater
with 5 micron filter,
UV light, and Carbon block

Rainwater collection can be simple or complicated depending on whether or not you've planned for it before building or are retrofitting an existing structure.  I recommend searching Amazon for books on rainwater collection, such as Design for Water.  While this book's information on rainwater collection is very good, it's information on rainwater purification is not.

Rainwater purification has grown more complex due to the spread of pollutants on trade winds that travel all around the planet.  Mercury from coal plants in China spreads to the entire Western US.  When collecting rainwater or spring water plan to purify for bacteria and the presence of mercury and pesticides.  Rainwater purification and rainwater filtration need not be complex or costly, but treating rainwater must be thorough enough to account for the pollutants likely to be present.  Mercury and pesticides are now present even in pristine environments requiring rainwater purification even in these locations.  Purifying rainwater is similar to what would be done for high quality mountain spring water.

If you're planning to drink the rainwater then my 4 stage Kitchen Defender with UV light is perfect for purifying rainwater or spring water.  ($470) In remote areas with no electricity you can use my 3 stage Kitchen Defender with ceramic filtration for bacteria is great ($285) but you'll have to use an electric or manual pump (a foot pump like those used on sail boats will work) or gravity to get the water to flow through the system. 


Click here to request specifications and pricing on the Kitchen Defender for Rainwater

To preserve the integrity of the Kitchen Defender from sediment you'll need to use a whole house 5 micron filter ($190).

For whole house rainwater purification you'll need my whole house rainwater system: Sweetwater's Whole House Rainwater Treatment with UV light.

Collecting rainwater will be unique to each building site but I've included a sketch and a couple of photos to provide some ideas on the approach.  You'll need to collect rainwater from a rooftop, filter the large debris and the initial wash, then store the water, and then pump it to your rainwater purification system.  Filtering rainwater with a large micron filter is a good idea but treating rainwater should take place after storage because it will be virtually impossible to keep the stored water contaminant free.


rainwater collection, rainwater purification, collecting rainwater


Also available as a pdf: rainwater collection system


Here are some ideas for collecting and purifying rainwater:

rainwater collection and diverter valve sketch


collecting rainwater, filtering rainwater, treating rainwater, rainwater collection

The above photo illustrates storage tanks used by a customer in Texas.


collecting rainwater, rainwater collection, filtering rainwaterWater is then piped to the point of use.

The photo on the right illustrates the overflow for the initial dirty water after a rain.

I can also provide whole house solutions including Sweetwater's Whole House Rainwater Treatment with UV light. Click on the link to request specifications and pricing.


DENVER (3-25-09) — Although rainwater collection is drawing new interest as an onsite water source, harvesting rain is against the law in two states and is limited in a third.

Utah prohibits rainwater collection, and Washington State allows it only in a few regions such as Seattle and the San Juan Islands, the Journal article said. (note: I believe that it is now legal in Colorado)

In the belief that such a ban makes no sense and is virtually unenforceable (penalties are vague in the law and rarely meted out), two Colorado legislators, state Rep. Marsha Looper (R-El Paso) and state Sen. Chris Romer (D-Denver), are trying to lift the ban on rainwater collection in their state.

The Wall Street Journal notes that rainwater collection bans originate in the West’s complex water rights laws. In Colorado, the law says that every drop of moisture in the atmosphere over the state is accounted for — those drops must be allowed to hit the ground and flow to various watersheds, where the water is divided up by law among the state’s many water users.

Critics note that people who filter rainwater for drinking will probably direct most of it back into the ground anyway close to where it would have fallen, to water plants and crops. But “powerful forces” in Colorado still don’t want any of it diverted, the article said.

Looper said she would like to put out a few rain barrels to grow hothouse tomatoes, but she won’t do it because “I don’t want to get thrown in jail.”


A recent attempt to lift a ban in Utah died in that state’s Legislature.


Request specifications and pricing on the Kitchen Defender

To preserve the integrity of the Kitchen Defender from sediment you'll need to use a whole house 5 micron filter ($190). 


If you'd like to discuss your specific project, give me a call.


 "What's in YOUR Water?"

James P McMahon, Jim McMahon, Sweetwater, LLC
James P McMahon

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