A mikveh was left empty and later found full with water. Is it valid?
Halacha 3 explicitly rules that a mikveh that was left empty and found full upon return is acceptable, as there is an unresolved doubt whether the water was drawn.
Question 2
There are two mikveot; three lugin of drawn water fell into one but it is unknown which. What is the ruling?
Halacha 2 rules that when drawn water fell into one of two mikveot but it is unknown which one, both are treated as valid due to the rule of leniency regarding mikveh doubts.
Question 3
A mikveh is found in a city in Eretz Yisrael. What is its presumed status?
Halacha 5 distinguishes: in walled cities of Eretz Yisrael, mikveot are presumed invalid; in open settlements (outside city gates) they are presumed valid.
Question 4
A person immersed in one of two mikveot — one kosher, one invalid — touched pure food, then immersed in the second. What is the status of the foods touched between the two immersions?
Halacha 7 states that if a person immersed in an unknown mikveh, touched pure foods, and then immersed in the other, the foods touched between the immersions remain of questionable purity.
Question 5
A water pipe fills a mikveh, but a mill is located next to the pipe. There is doubt whether the water came from the pipe or the mill. Is the mikveh valid?
Halacha 4 rules that when a known source of disqualification is evident — the mill — the mikveh is invalid even though there is doubt, because the disqualifying factor is demonstrated.