Miva’ot are typically built with two pools, one with rain water and one with pumped water. The two pools are connected by means of hashaka (a pipe with ⌀ > 5 cm).
Immersion takes place in the pool with pumped water, which can be regularly drained, cleaned, and refilled.
Should the pool of rain water be next to the immersion pool with the two connected by hashaka?
Or should the pool of rain water be underneath the immersion pool with a hole in the floor of the immersion pool to connect it with the rain water?