Rainwater catchment system for my Parents

My parents would like to collaborate with me on a rainwater catchment system for their home which gets a lot of rain. We're hoping that I can design it over the next couple weeks, my Dad can acquire the parts and materials over a couple weeks after that, and then we can put it together over 10-14 days while I'm visiting.

We're hoping to use the backside of their garage as the catchment "surface" and have the gutters and downspouts empty into a pair of water tanks which will pump into a large water tank about 40 feet away. We'd like to elevate that large water tank somehow so that gravity can be used to feed water from the tank to the vegetable garden below.

Is this a good plan? The garage has asphalt shingles. Is water that has washed over asphalt shingles unsafe to water a vegetable garden with? My Dad says he's willing to have the roof re-done if necessary.

The measurements of the backside of the garage roof are 35' x 12.5' plus 24' x 6'. Any thoughts on this?

You should look into changing a few things right away. Let no water enter your system from an asphalt / composite roofing material. Your tanks will most likely be polluted by the roofing materials. You have a couple of choices and cost are a factor here with roofing materials. A metal roof replacement might run you $240+ per hundred sq. ft. but this is a long term fix and well worth the investment. The second "possible" solution might be to go with a rubber or poly roof cover over a foam or cardboard base. This will never last very long and is not the better choice at all but if your in need today & don't have the funds it works. until you can put metal on the roof..

As to the "40 feet away tank" for storage you might consider to let gravity be your best friend in the collection also, a hand built tank at the base of the foundation (of the building your using to collect at ) combined with a drop a sediment filter , falling into storage tank will eliminate any pumping as you had noted. It's really never a good plan to add mechanical systems for the storage side , if possible. Were in the process of making changes to my Companies web content but, If I'm not mistaken we have had a drawing & videos at our web site ( or I will re-post them later ) that might better define "a hand built tank" and Greywater systems too.

Pumping to your house or garden and any filtering as may be required, can then come after adequate initial storage has been achieved and will better assure you that a mechanical failure won't impede your harvest of the rainwater. Rainfall does tend to come quickly and that doesn't leave much time to fix pumps , that move water to other tanks should they quit during a rain event.

I Hope that helps you some !

Best Regards,
Joe Woodall, Rogue Eco-Architect
Georgia Adobe
http://www.georgiaadobe.com

Thank you Joe! I will take your advice on the roofing materials and look into switching to a metal roof right away. I should have mentioned before that the storage tank that is 40 feet away will also sit on ground which is higher by about 5 feet. Because of this I think we will need to pump the water to that tank. I'd like to elevate that storage tank even higher somehow so we can use gravity to feed the water to the vegetable garden below. This water will only be used for the vegetable garden so we aren't planning on doing any filtering. I would love to see your drawing and videos. Please let me know when you locate them!

Hi Joe, have you had a chance to find the video and drawings?

How did this task finish up?