Does anyone have a DIY setup to divert water from downpipe to swimming pool?

Answer 1

I'm assuming the downspout is higher than the pool.

The main concern I would have is ensuring any particulate matter from the roof is removed before the water gets to the pool. This should be easily done by directing the water from the roof into a barrel where the particulates can settle out, and then taking water from near the top of the barrel to the pool.

I'd suggest using black ABS tubing (usually sold for home drainage systems) and matching fittings for this project. They are readily available in a range of sizes and a wide variety of fittings and couplings are available and the pieces can be glued securely with ABS cement.

I'd suggest a "40 gallon" plastic barrel (available from many recyclers) with a removable top (not one with bungs since they would likely be too restrictive under high rain conditions). I've purchased these for $10-$20 in different styles.

Lead a flexible hose from the end of the downspout through the top of the barrel and down to about 12" from the bottom. Attach another hose or length of 3" pipe to a 3" fitting attached to the side and about 6" below the top of the barrel. The hose or pipe should lead slightly downhill and empty at a suitably out of the way location into the swimming pool.

The rainwater in the barrel could also be used to provide water for the garden if a hose coupling is fixed to the bottom of the barrel. That way, when it rains the barrel will first fill and then drain excess roof water to the pool.

Note it is important to ensure none of the tubes/pipes or fittings downstream from the downspout restrict waterflow. In other words they need to be at least as big a diameter as the downspout.

Answer 2

Depends how far the spout is from the pool.
If it is only a few feet, there are several flexible hose attachments for downspouts to redirect the output.
If it is farther, direct the water into a cistern (barrel) with a hoes attached near the bottom and let gravity "push" the water where you want it.