Niddah 67a: Rabbi Yochanan said: If a woman opens her eyes too wide, or shuts them too tightly, her tevilah is not effective.
Rema Yoreh Deah 198:43: Some say that a woman must go to the bathroom before immersion in the mikvah, if she needs to, because if she holds herself back, her insides would not be accessible to the water.
נדה סז ע”א: א״ר יוחנן: פתחה עיניה ביותר, או עצמה עיניה ביותר ־ לא עלתה לה טבילה.
שולחן ערוך יו”ד קצ”ח מ”ג רמ”א: יש אומרים שהאשה צריכה להטיל מים קודם טבילה אם היא צריכה לכך גם צריכה לבדוק עצמה בגדולים ובקטנים שלא תהא צריכה לעצור עצמה ולא יהיו ראויים לביאת מים.
On one of the Satmar Rebbe’s trips to Eretz Yisroel, he passed through Switzerland, and Rav Mordechai Yaakov Breisch zt”l, rav of Zurich and author of Chelkas Yaakov, accompanied him on the train. In the course of the conversation, the Rebbe asked him, “What have you accomplished in your city?”
“I had toilets installed in each room of the women’s mikvah,” replied Rav Breisch.
“And why was that so important?” asked the Rebbe.
“Because if a woman feels the need to use the bathroom, but holds herself back during her tevilah in the mikvah, according to the Rema (Yoreh Deah 198:43) it is a chatzitzah. But if there is a toilet in every room, she can go whenever she wants, so she will be less likely to hold herself back.”
The Rebbe thought deeply for ten minutes, He was clearly very impressed, and his face was aflame. “Ah!” he exclaimed. “Every little piece of gashmius that you put into a mikvah is completely ruchnius!”
Source: Rabbi Yissachar Ber Teitelbaum, supervisor of the mikvah in the Zupnik Building in Williamsburg, who heard it from Rav Breisch’s grandson
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