Filling pool with rain water - do or don't ?


LifeTime Supporter
Apr 10, 2009
Toronto, Canada
I have a way to redirect all water from the house roof (roof drain) to the pool. This will save me a lot in the water bills, but are there any downsides in doing it (I understand that water should be clean of dirt and debris) ?



LifeTime Supporter
Mar 7, 2009
Texas (Central)
We used about 5,000 Gallons from our 10,000 tank of rainwater to fill our 17000 gallon pool...
don't know of any ill effects....
Why rainwater may work for me... I collect with a standing seam metal roof. Have been using it for several years.
The other water in my pool is hard, alkaline well-water. I usually tend to high Ph.


TFP Expert
LifeTime Supporter
Nov 5, 2008
I do know that some roofs are treated with zinc to prevent algae & mildew staining. I read cautions against letting such roof water go into fish ponds. I have no idea if zinc at that level might be bad for a pool, if you had that sort of shingle that is mildew proof.


Well-known member
Apr 30, 2007
Only down side I can think of is that most rain is acidic so that you will have to add chemicals to raise the pH -- I know my pool pH always drops after a heavy rain.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
The advisability of using roof runoff for the swimming pool depends on the kind of roof and how old it is. this web site provides a quick overview of the various kinds of roofs and how safe water running off of them is.
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