Pond Management and Sizing

For the three ducks I've had a cheap, plastic kiddie pool works great. I don't think it would work well for 6-12 ducks, though. With just three I had to drain and rinse it every couple of days. Daily emptying would be very expensive given water rates in colorado.

If I were to plan a pool for that many I'd probably start with something with a footprint of at least 15sq ft. It would have to be at least twice as big as the amount of space required to fit all of the ducks in at once.

I'm about to start building a new one myself. I'm using a pre-fab plastic pond liner. It'll be elevated and sitting on a landscape stone foundation. I'll put a big drain in the bottom with PVC piping that leads away from the pool and drains into the garden. If you're going to pay for the water you might as well use it as many times as you can.

I'm sure others here have better guidelines. Just keep in mind that ducks are incredibly efficient at making messes. Especially in their water.