If a drop of Tuma liquid (say a "Mashke" of a zav) falls into a huge vat of water, do we say that all the water is now an Av, or do we say it could get nullified.

If it gets nullified, at what ratio?

(It doesn't make sense to say 60, because no taste is involved.)

  • each tuma has its own minimum shiur. spit i think is kol-shehu as we find in the talmud kohanim becoming tamei from miniscule drops of spit that fell on them from speaking with am-haratzim
    – ray
    Dec 24, 2013 at 20:27
  • @ray lets say a minimum shiur falls into a huge vat. Dec 24, 2013 at 20:30
  • that was the case by the kohen. miniscule saliva on human being is thousand folds+
    – ray
    Dec 24, 2013 at 20:31
  • 1
    @ray saliva doesn't blend in with humans, and there is no bittul when it is recognizable Jan 24, 2014 at 2:55
  • possibly relevant Hilchot Tum'at Okhalin 16:4
    – Double AA
    Mar 31, 2014 at 19:10

2 Answers 2


Rambam Metammei Mishkav uMoshav 2:6 says that if a Zav's saliva fell into water and it dissolved into the water then everything is Tahor assuming the water hasn't changed color. Looking at further cases there (eg. urine of a Zav mixed with urine of a Tahor person) it seems that in general we go by majority assuming the item in question isn't still detectable by color or texture.

(See too Tosefta Tohorot 5:1, Mordechai Chullin 737 about BK 25a.)


I think that the following halochos indicate that there is no bittul of the Rabbinic tumah of liquids.

Rambam Hilchos Shaar Avos Hatumah Chap 7 says:

Halocho 1: (Food that contracted impurity does not impart impurity to other foods according to Scriptural Law.) Nor do liquids that contracted impurity impart impurity to other entities according to Scriptural Law. Nevertheless, according to Rabbinic Law, it was decreed that impure food that touched other foods would impart impurity to them. Similarly, if impure foods touched liquids, the liquids are impure.


Halocho 5: With regard to liquids, by contrast, whether a liquid touches a primary source of impurity, a primary derivative or a secondary derivative, that liquid is considered as a primary derivative. It imparts impurity to another liquid, which in turn can impart impurity to another liquid, even if there is a chain of a hundred. For there is no concept of degrees of impurity with regard to liquids.

  • 2
    Mashke of a Zav is a biblical Av haTumah.
    – Double AA
    Dec 24, 2013 at 20:38
  • @DoubleAA Thank you. So for that case I guess it is a kal vechomer that it is not nullified at least miderabbonon. Dec 24, 2013 at 21:25
  • 1
    @AvrohomYitzchok I davka didn't choose Derabanan since Rabbinicaly a sheini which touches an liquid makes the liquid into an av. Dec 26, 2013 at 4:02

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