The laws of mikveh are found in the Torah in the book of Vayikra (Leviticus), and are discussed extensively in the Mishnah in tractates Niddah and Mikvaot, in the Talmud in numerous places but most extensively in tractate Niddah, and in the Shulchan Aruch in Yoreh Deah 183-200. It would take volumes to list all the relevant sources, which are found in these books and many more.
Unless you are already a highly accomplished scholar, you will find it extremely challenging to embark on a study of the primary sources – even in English – without sufficient guidance. The amount of material is overwhelming and requires years of intensive study before it can be properly understood. Moreover, much of the material is not directly relevant to the practice of these laws today, and many passages can be misleading if taken out of the broader context of the halachic tradition as it has developed over centuries. Therefore we suggest that you either find a rabbi or teacher who can guide you in your study, or else read a good contemporary book on the subject which cites sources for the laws. Some excellent resources in English (in alphabetical order by author) are:
- Rabbi Shimon D. Eider. Halachos of Niddah. New York: Feldheim. A clear, practical, and detailed presentation of the laws of niddah and their underlying concepts. Includes wonderful Hebrew footnotes with extensive references to primary sources. This book covers the laws of becoming niddah, the taharah process, and conduct while niddah, but unfortunately does not include important topics such as mikveh immersion and vestot.
- Rabbi Binyomin Forst. A Woman's Guide to the Laws of Niddah. New York: Mesorah Publications, 1999. 373 pages. A clear, practical, and very detailed guide to the laws of niddah. Includes a special section for kallot (brides).
- Rabbi Binyomin Forst. The Laws of Niddah: New York: Mesorah Publications, 1997 (vol. 1), 2002 (vol. 2). Two volumes, 527 & 579 pages. Much of the material in this book is found in A Woman's Guide by the same author. This is a more complex and theoretical presentation, following the order of the Shulchan Aruch, with extensive footnotes.
- Rabbi Aryeh Kaplan. Waters of Eden: The Mystery of the Mikvah. New York: NCSY/Union of Orthodox Jewish Congregations of America, 1976. 91 pages. A philosophic and mystical exploration of the concepts of mikveh and purity. Ten pages of endnotes citing a wide range of primary sources.
- Rabbi Elyashiv Knohl. The Marriage Covenant. Ein Tzurim: Yeshivat HaKibbutz HaDati, 2008. 297 pages. A clear and friendly guide to Jewish marriage. Includes a thorough and detailed presentation of the laws of niddah and the principles behind them, as well as the emotional and psychological aspects of marriage.
- Dr. Deena R. Zimmerman. A Lifetime Companion to the Laws of Jewish Family Life. Jerusalem: Urim Publications, 2005. 224 pages. A straightforward, practical, and detailed guide to the laws of niddah and their interplay with women's health at various stages of the life cycle. Includes Hebrew citations of primary sources and extensive discusssions of medical issues. The author is a physician and a yoetzet halacha. This book can be purchased in stores or through www.urimpublications.com.