[permaculture] Roofing materials and water collection

Lawrence F. London, Jr. venaurafarm at bellsouth.net
Sat May 14 00:33:32 EDT 2011

On 5/14/2011 12:31 AM, Lawrence F. London, Jr. wrote:

> question put to Google like:
> "toxicity problems with rainwater collected off metal roofing"
> Tried that phrase and got:
> Information on Zinc Oxide in Construction - Zinc Metal Roofing Systems
> The run-off water can contain zinc ions. Since zinc is an element
> essential for life and most organisms ... For instance, rainwater
> collected from VM ZINC roofs, can be used without any known problems for
> watering plants. ... Actually there are many types of heavy metals some
> that are toxic and some that are not. ...
> www.metal-roofing-zinc.com/zinc_roofing_basics.htm - Cached - Similar
> and:
> http://www.homesteadingtoday.com/archive/index.php/t-376478.html
> Key reply:
> "I wouldn't drink rainwater off a roof unless it had been sterilized by
> some means, boiling or chlorine or such. Bird poop can carry some nasty
> parasites and pathogens. You can do it, and get away with it, but it is
> a gamble."

And a few online manuals in PDF format:

The Texas Manual on Rainwater Harvesting
File Format: PDF/Adobe Acrobat - Quick View
by R Harvesting - Related articles
Metal. The quantity of rainwater that can be collected from a roof is in 
part a function ... assuming no toxic sealant is used; however, cost 
considerations may ... running off the eaves of a building. Some gutter 
installers can provide ..... potential problem of leaking from an 
aftermarket fitting. Polypropylene ...
www.twdb.state.tx.us/.../rainwaterharvestingmanual_3rdedition.pdf - Similar
Chapter 7: Water Collection
File Format: PDF/Adobe Acrobat - Quick View
9 For water quality issues, contact the New Mexico Environment ... 
Figure 7-1: A pitched metal roof is the most efficient catchment surface 
for rainwater harvesting. ... When the collected water is designated for 
nonpotable uses such as ... and low toxicity. When choosing a surface 
for a new roof, it is important ...
www.ose.state.nm.us/water-info/.../pdf.../Roof.../RRL-Chapter-7.pdf - 

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