4,011. The Water for Sanctification

Hilchos Bias HaMikdash 5:11

If one immerses his hands and feet in a mikvah – or even in a spring – they are not sanctified; sanctification is only accomplished by washing from a vessel. One may use any service vessel regardless of whether or not it can hold a reviis (about 3.3 ounces).

Hilchos Bias HaMikdash 5:12

Any water can be used for sanctification – whether from a spring or a mikvah – so long as its appearance hasn’t changed and it’s valid for immersion. Mud that is so runny that it can be poured and a cow would drink from it can be used to finish filling up the kiyor (the basin). The general rule is that any water that can be used to finish filling up a mikvah can also be used to finish filling up the kiyor.