[permaculture] Roofing materials and water collection

Robyn Francis robyn at permaculture.com.au
Fri May 27 19:32:28 EDT 2011

Hi Jason, 
if you've a first flush diverter, ensure that light and critters cant get
into your tank and don't disturb the biofilms by cleaning the tank (just
clean the gutters & organic build up on the roof eg leaves in fall), then
the water should be fine and safe for drinking unless there's serious
airborne pollutants in the actual rain (such as ag chemical spray drift from
neighbouring farms).

We have only untreated roof collected rainwater here for our potable water
supply and over the past 18 years many thousands of people (students &
visitors to our pc centre and college) have drunk the untreated rainwater
with absolutely no problems at all. Many have never drunk rainwater before
and have had no ill effect whatsoever. We've never had anyone get sick from
our rainwater. 
BTW I often have friends from town come and fill up containers of our
rainwater to take home for drinking as they don't like or trust town water.
The Nimbin Community Centre in the village has a rainwater tank where locals
refill water bottles when they're in town - that's how much we love, trust
and treasure our rainwater for drinking here. :)

On 27/05/11 1:51 PM, "Jason Gerhardt" <jasongerhardt at gmail.com> wrote:

> Glad this topic came up again. I am finishing up teaching a PDC in Arizona
> where water has been a main thread of conversation. At Brad Lancaster's home
> in Tucson he said he currently drinks water off his galvalum roof without
> problem. He has yet to test his water quality however. After talking with
> many people on this subject I've determined essentially that Darren
> Doherty's comments on this thread are what holds true. Each individual will
> likely adapt to their specific water quality or lack thereof. Brad wouldn't
> let others drink his water since he believed he was adapted to it, but did
> not want to risk offering it to others.
> I also hear that ARCSA (American Rainwater Catchment Systems Assoc.) has a
> ton of information on this issue. According to an attendee of a recent ARCSA
> conference, researchers in Australia have found that rainwater is basically
> very pure regardless of the surface it runs off of, even asphalt shingles.
>> From what I understand, the biofilm inside the tank (or the bacterial film
> that clings to the sides of the cistern) are a key element in keeping the
> water clean. When this biofilm is cleaned away the water quality actually
> goes down.
> Brad Lancaster suggested if one were worried about water quality from roof
> runoff for drinking water that it could simply be run through a home
> purifier.  He suggested Potter's for Peace, which makes a simple colloidal
> silver filter for unpressurized systems.
> For what it's worth,
> Jason
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Permaculture College Australia inc
Pathways to sustainability through
Accredited Permaculture Training
Certificates III & IV and Diploma of Permaculture
PDC and short courses

Robyn Francis 
International permaculture design and
sustainability consultant, educator & facilitator

Djanbung Gardens 
Permaculture Education Centre & Demonstration Farm
PO Box 379 Nimbin NSW 2480
02-6689 1755  /  0429 147 138

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