# Downspout Storage / Drainage



## ShilpaMann (May 12, 2018)

I have a post on here somewhere about a drainage project that unfortunately has fallen victim to my constant revision issue I have. However, outside of one relatively expensive valve, I think I have come up with a solution to my drainage/irrigation ideas, and was hoping someone on here might be able to tell me why this is a bad idea.

*Goal:*
Draining 3 of my 4 downspouts into storage tanks, and overflow will drain out into my yard.

I am only willing to have enough room for 3x 275Gal tanks on the side of my house; where I live, this should be plenty for my needs, since we get quite a bit of rain for most of the year, and this is solely for raised gardens. Originally, I was going to have holding tanks at each downspout, and they would connect to each other with 1/2"-1" piping (I would then connect hoses/irrigation/etc to this line). As well, I would have 4" PVC running around my house to catch overflow from each tank (aka: to route water from downspouts away from the home), which during a normal storm, I will have considerable overflow (last night, for example, I could have filled my tanks ~4x, and it wasn't even a big storm).

New plan: eliminate holding tanks at the downspouts (aesthetically unpleasing, two downspouts are located in very visible locations), extend the 4" PVC up to higher than the tops of the tanks, and have a single overflow/spillover to deal with excess. This accomplishes a few functional things:
1. Should dramatically reduce leaves/dirt/grit from the roof from going into my tanks (Note: I presently don't have any issue with leaves, but maybe I will in the future).
2. Eliminates doubling up of the pipes (the 4" pipe will serve as supply AND drain).
3. The 4" pipes will actually hold a decent amount of water (about 75 gal for the whole system).

Here's a diagram of the proposed system that will be wrapped around my house; the elevation is accurate, so you can see how this is supposed to work. The valve is the part I am questioning the most, but it's needed because it freezes here, so it will be "open" when it's cold, and opening that valve will hopefully make flushing the lines seasonally a LOT easier (open it, the water-column in the downspouts will push a 4" diameter column of water through the pipes).



Issues I potentially see:
1. Cleaning will be a bit of a bear, but probably not an enormous deal. I will only need 2-3 cleanouts to ensure I have access to all straight runs, and the 4" valve should flow well enough to help blast out grit (which SHOULD collect on the back of the valve).
2. 4" pipes 5' up the side of the house might look silly.
3. Ice in that 4" valve. In the winter, that thing will be open, so will only have snow runoff/small amounts of water in it, and it will be in an underground box, so I'm not sure how much that is going to be an issue.
4. Leaks will suck (though VERY unlikely to happen).


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