Get to know the terms related to mikvah observance.


Any time blood leaves a woman’s uterus not due to trauma. From the Start of Flow until the wife’s immersion in a mikvah, she and her husband must follow the laws of Niddah conduct. This includes refraining from physical relations.

Start of Flow

The date and hour that a woman first notices her flow.

Hefsek Tahara

Internal Examination with a white cloth to ascertain that bleeding has completely ended. According to most opinions, at least five days must elapse from the Start of Flow before performing a Hefsek Tahara. Some Sefardic opinions require only four days.

Seven White Days

Seven consecutive days between the Hefsek Tahara and Mikvah Night. The woman performs two internal examinations each day (bedikot) between sunrise and sunset. If blood is found, she must perform another Hefsek Tahara as soon as she is able and start her Seven White Days from the new Hefsek Tahara.

Mikvah Night

Immediately following the woman’s seven white days. After emerging from the mikvah, the woman enters the new status of “Tehorah” or “Pure”. A woman may not immerse in the Mikvah on the nights of Yom Kippur, Tish’a B’av, or a night of one of her Anticipated Flows (Vestot). In these cases, Mikvah night would be pushed off until the following night.

Anticipated Flow (Veset)

Relations are not permitted during an Anticipated Flow.

  • Interval Cycle (Veset Haflagah): The same interval between the previous flow and this flow. This is calculated differently according to various customs.
  • Monthly Cycle (Yom HaChodesh): The same daytime or nighttime period of the Hebrew Month in which her previous flow began.
  • Average Cycle (Onah Beinonit): 30 and/or 31 days after the start of the previous flow. (Depending on your custom.)

Veset kavua (regular veset) has the most advanced Kavuah system in the world. Detecting, calculating, and reminding our members of their various Kavuah patterns.


Internal Examination with a white cloth. A woman must perform the internal examination with bedikah cloths on a few occasions:

    • Hefsek Tahara: An internal examination which ascertains that her menstrual Flow has completely ended (as stated above).
    • Two times on each day of her 7 White Days. (If the twice-daily checks were not fulfilled, the seven days are still valid, as long as she checked at least once during the first day and once during the seventh day. If the required examinations are difficult to perform, she may rely on certain leniancies after consultation with an orthodox Rabbi expert in these laws.)
    • During her Anticipated Flows (Vestot): A woman must perform an internal examination during her Anticipated Flow. There is an extra stringency regarding Average Cycle. The couple may not resume relations until she has performed a clean examination (even if her Average Cycle has passed). Some poskim require 2-3 internal examinations on veset days. If you are not sure, you should ask your Rabbi.
    • Ashkenazic custom is that the woman can perform the internal examination at any time during the Anticipated Flow.
  • Chabad custom is that the woman should perform the examination no earlier that the same time of day as the Start of Flow of the cycle which projected this Flow.

Half-Day (Onah)

From Sunrise to Sunset (Day) or Sunset to Sunrise (Night)


From Sunset to Sunset which is a full Hebrew Day.