A woman in a state of niddah returns to a state of taharah (ritual purity) only after immersing in a body of water that meets the halachic criteria for a mikveh.
It is preferable to immerse in a recognized, halachically supervised mikveh. However, immersion in a natural body of water is valid as long as it conforms to halachic requirements. This type of immersion can be a unique spiritual experience.
An ocean is normally acceptable for immersion, as is a natural lake fed by river water or springs. A flowing spring or river can be acceptable for immersion when most of the water originates from a spring and not from collected rainwater. When most of the water in a spring, river, or lake is from rainwater, then only stationary water there is fit for immersion. Sometimes, whether a body of water is fit for immersion varies seasonally.
Since these halachot are quite complex, it is important for a woman to verify with a local halachic authority that the specific body of water she is considering is actually kosher for immersion.
A woman needs to take a few considerations into account in choosing a suitable location for immersion:
- Safety The location needs to be safe. Safety is a critical halachic consideration and should be clarified before making any plans to immerse.
- Privacy The location should have sufficient privacy. A woman’s concern that others might see her could lead to a rushed and improper immersion.
- The Ground Thick mud that will adhere to the feet could create a chatzitzah. Standing on an object that halacha considers a “keli” (vessel), e.g., a pot or a chair, could invalidate immersion, and thus would not solve the problem of standing on mud. A flat wooden plank with no lip can be used as a base to stand on if necessary. If there are concerns about the floor of the body of water, a halachic question should be asked.
Immersing in a natural body of water often raises the following halachic considerations:
Modesty
A woman may immerse wearing a loose-fitting long shirt or robe that allows the water to reach all parts of her body. Alternatively, if there is sufficient privacy, she may enter the water with a robe or other easily removable garment and remove it under water.
Timing
In pressing circumstances, as when a location is unsafe at night, a question should be asked about the timing of immersion. A woman in this situation may be permitted to immerse on her scheduled mikveh night after sunset before nightfall. Alternatively, immersion may be permitted during the daytime following mikveh night.
Following immersion during the daytime, the couple may not have relations prior to nightfall. In this scenario it is preferable for the couple not to see each other between immersion and nightfall. If this is not feasible, they should avoid being secluded alone together.
Supervision
Mikveh immersion should be supervised in order to ensure that all hair is submerged. The site needs to be sufficiently well-lit for the person watching to be able to see this.
With a natural body of water, supervision can also be essential for safety.
Any halachically observant Jewish woman over the age of twelve can supervise immersion. If no woman who meets this description is available, a woman can immerse without supervision if a she has short hair or can otherwise ensure that her hair is thoroughly submerged, as with a loose hair net (cutting the elastic so that it is not tight against the head).
Alternatively, a woman’s husband can observe the immersion. Since it is not permissible for him to see her unclothed while she is niddah (even moments before immersion), she should be especially careful with modesty (as above).
Additional halachic issues can arise when a woman needs to immerse in a natural body of water on Shabbat or Yom Tov. In some cases, these can be resolved with some advance planning. In other cases, immersion may need to be postponed until after Shabbat.
- The laws of techum Shabbat prohibit walking more than 2000 amot (approximately a kilometer) beyond a built-up area on Shabbat and Yom Tov.
- Wringing out liquid is prohibited on Shabbat and Yom Tov. A woman should not wring out any garment she wears into the water, and should only pat her hair dry, rather than wringing it.
- Carrying outside an eiruv is prohibited on Shabbat (but not on Yom Tov). A woman can wear an absorbent robe, or wear her towel like a shawl rather than carrying it. She should place the robe or towel within four amot (about two meters) of the water before going in, so that she can dry herself off immediately upon emerging from the water and thus avoid carrying excess water on her body.