The Mikvah ceremony is an ancient Hebrew ritual of purification. The matriarch Sarah, the first Jewish woman, and wife of Abraham, instituted sacred women’s ceremonies that have been passed down through the generations between mother, daughter and sister for the last four thousand years.
Judaism is an ancient matrilineal culture that reveres women's power, and it teaches that women are 'closer to the God' because of a woman's ability to bring life into the world. Emerging from a mikvah that is filled with natural ‘living waters’ is symbolic of the birth of life.
Because sex is sacred in Jewish tradition, the first required Mikvah immersion for a woman takes place before her wedding ceremony to consecrate the joining together of man and woman in marriage. And, every month thereafter, following a time of sacred sexual separation and reunion that coincides with the beginning and ending of her menstrual cycle, the woman performs a Niddah menstrual purification mikvah ceremony before re-uniting with her husband.
Some observant Jews use the Mikvah to purify themselves on Friday afternoon in preparation for Shabbat and before major holidays. Even so, the Niddah is the most commonly performed mikvah ceremony.  While it is the woman’s responsibility to perform the monthly Niddah purification ritual to ensure family purity, men and women may both use the mikvah to mark significant transitional moments. 
According to Rivkah Slonim, the traditional position states the following:
“Within that consecrated union, the expression of human sexuality is a mandate, a mitzvah. In fact, it is the first mitzvah in the Torah and one of the holiest of all human endeavors. … . . In their fusing and meshing, man and woman . . . . draw on, and even touch, the Divine. They enter into a partnership with God; they come closest to taking on the godly attribute of creator. In fact, the sacredness of the intimate union remains unmitigated even when the possibility of conception does not exist. . . . 
. . . and each month it is a mitzvah for husband and wife to draw renewal from the waters of the mikvah. . . . Through mikvah she brings herself in immediate contact with the source of life, purity, and holiness - with the God who surrounds her and is within her always.”

Natural bodies of water, oceans, wells, and springfed lakes, ponds, rivers, and streams, are all mikvahs.  Traditionally, when these are not available a mikvah bath, built according to specific Jewish laws and regulations, is constructed for the Jewish community. 
This ceremonial pool is designed for immersion and, according to orthodox tradition, contains 200 gallons of fresh rainwater. When rainwater is not available, ice or snow originating from a natural source may be used to fill the mikvah. 
The Mikvah ritual includes specific tifilot or prayers, a sacred kavana, or intention, followed by ritual immersion in a natural body of water, or in a pool of natural water. 
Not all Jewish men and women practice Mikvah ceremonies, and Judaism is going through a spiritual renewal.  For many, the mikvah is being revived as a powerful and meaningful ceremony for bringing the sacred into our secular life-styles.
 For example, Jewish author Anita Diamant, who writes about the Jewish Matriarch’s Rebecca, Leah and Rachel’s sacred menstrual ceremonies in her best selling book The Red Tent, met with team of rabbis, cantors, psychologists and poets to found Mayyim Hayyim Mikvah in Boston.  
Mikvah ritual infuses transitional moments with sacred intent to consecrate life-cycle events. This team identified 7 different traditional themes for Mikvah ceremony including:
1.	Immersion Ceremony for Bride, 
2.	 Immersion Ceremony for Groom 
3.	Niddah –Family purity ceremony 
4.	Ceremony for the New Year 
5.	Ceremony for Yom Kippur
6.	 Healing Ceremony 
7.	Celebration
Mayyim Hayyim has prepared ceremonies for each of these intentions using an inspired blend of the traditional prayers, combine with these sacred intentions to consecrate a wide range of transitional events. Included are mikvah ceremonies for divorce, chemotherapy, miscarriage; or the anniversary of the loss of a loved one, to counting the milestones in recovery from addiction, conversions, or marking other new beginnings, including celebrating graduations, becoming grandparents, birthdays, adoptions and other joyous occasions.  
Sample ceremonies are available on-line at Mayyim Hayyim at  www.mayyimhayyim.org.  And for more information about Jewish Renewal, visit Aleph at http://www.aleph.org/kallah.html