Editing Hovaya Al Yedei Tahara (Creation Through Purity) (section)

== Practical Implications ==
This halacha has many practical implications. The mikvah water must not enter through any item that can receive tumah. Therefore, if one places metal, food, drink, or any vessel that can receive tumah in the place where water enters the immersion pool, the water becomes invalid for immersion. For this reason, a person is also forbidden from directly throwing water into the immersion pool, unless it is done through hamshachah (drawn water), where the water is poured at some distance from the immersion pool and then flows into the mikvah.

Additionally, the pool itself must not be made from materials that can receive tumah - not just in its entirety but even partially. If even part of the immersion pool's walls is made from material that can receive tumah and supports the mikvah, the mikvah is invalid for immersion.

The poskim (halachic authorities) address two concerning situations: The more severe one is when there is a hole at the bottom of the pool that supports all the water. The Divrei Chaim of Sanz addressed such a mikvah: "At the floor of the mikvah there is a large hole for draining the water to clean the mikvah, with a metal plug blocking this hole except when needed for cleaning the pool. When this metal plug is removed, the pool remains empty without water - this is the essential construction of these mikvaos as I have seen in several places. According to this, all the water in the mikvah is supported by this metal, meaning the entire existence of the mikvah depends on something that can receive tumah, as simple metal vessels can receive tumah."