In Jainism, chanting the Navkar Mantra (Namokar Mantra) is considered highly auspicious and spiritually beneficial. When performing any kind of tapasya (austerity or penance), including fasting or observing dietary restrictions, it is a common practice to chant the Navkar Mantra three times before and after consuming water. This practice has deep significance:

1. Purification of Intentions: Before breaking the fast or tapasya, chanting the Navkar Mantra helps purify your mind and intentions. It reminds the practitioner to maintain spiritual focus and humility, dedicating the act to the Arihants, Siddhas, Acharyas, Upadhyays, and Sadhus.

1. Expression of Gratitude: By chanting before drinking water, the practitioner expresses gratitude for the opportunity to perform tapasya and acknowledges the spiritual guidance of the Panch Parameshti (the five supreme beings).

1. Minimizing Karma: The act of consuming water, even during austerities, might inadvertently harm microorganisms. Chanting the Navkar Mantra is a way to seek forgiveness and minimize the karmic impact of such actions.

1. Completion and Reflection: After having water, chanting the Navkar Mantra again marks the completion of that phase of tapasya. It allows the practitioner to reflect, offer thanks, and reaffirm their spiritual goals.

1. Jain Tradition and Discipline: This practice instills discipline, mindfulness, and a sense of sanctity in every act, even those as simple as drinking water during tapasya.

In summary, chanting the Navkar Mantra three times before and after having water during any tapasya is a way to spiritualize the act, maintain purity of thought, and remain connected to the core principles of Jainism.