If by “gud water” you mean the Jain way of offering pure water (Jal Abhishek) to the Tirthankar, here is a simple, authentic method that both Shwetambar and Digambar traditions accept, with small local differences.

Purpose

• Jal Abhishek is done with deep devotion to remember the pure qualities of the Tirthankars and to purify one’s own thoughts. It is not for worldly wishes.

Preparation

• Personal purity: Bathe, wear clean simple clothes used only for pujā.
• Ahimsa care: Use clean, room‑temperature water filtered through a fine, clean cloth to avoid harming tiny beings.
• Place: Clean vedi/altar, keep the idol/mūrti on a stable sinhasan. Keep a separate, clean cloth for gently drying the idol.
• Utensils: A clean lota/kalash reserved only for pujā. Do not mix with kitchen use.

Steps 1) Inner resolve (bhāv) - Stand calmly, fold hands, and mentally bow to Arihants, Siddhas, Āchāryas, Upādhyāyas, and Sādhus.

2) Recite Navkar Mantra - Chant Navkar Mantra slowly 3, 9, or 27 times, focusing on the virtues.

Navkar Mantra (Prakrit) - Namo Arihantanam - Namo Siddhanam - Namo Ayariyanam - Namo Uvajjhayanam - Namo Loe Savva‑Sāhūnam

Simple meaning - I bow to Arihants (perfected beings who teach), Siddhas (liberated souls), Āchāryas (heads of the Order), Upādhyāyas (preceptors), and all Sādhus (monks). This mantra purifies the soul.

3) Offer the water (Jal Abhishek) - Gently pour the filtered water from the lota over the idol. Keep a steady, respectful flow; avoid touching the idol with the vessel if your temple/home maryādā says so. - Continue chanting Navkar Mantra or Logassa Sutra with devotion. - Use only as much water as needed; Jain practice values aparigraha and non‑waste.

4) Drying and adornment - Gently dab the idol dry with the clean cloth kept only for pujā. Do not rub harshly. - If your tradition allows, you may apply a light chandan tilak thereafter. Avoid flowers/leaves, as Jain maryādā generally discourages plucking.

5) Disposing the water (very important) - Do not let abhishek water go into drains. Collect it carefully and pour it at the roots of a tree/plant in a clean place, honoring ahimsa.

Timing and conduct

• Prefer morning, in daylight hours. Maintain silence, mindfulness, and non‑violence throughout.
• Refrain from eating/drinking during the pujā; complete it with humility and a short meditation (samayik‑bhāv if you observe it).

Notes on traditions

• Shwetambar temples often perform Panchamrut (milk, curd, ghee, sugar, honey) first, followed by Jal Abhishek. In many Digambar maryādās, simple Jal Abhishek is preferred; Panchamrut may not be used or is performed differently. Follow the maryādā of your temple/home and your guru’s guidance.

Key principles to remember

• Ahimsa: filter water well; avoid harm to even the tiniest life.
• Aparigraha: use minimal, necessary quantities.
• Shuddhi: keep utensils, cloths, and place reserved and clean.
• Bhāv: focus on virtues, not on material wishes.

If by “gud water” you meant something else, within Jain practice the spiritually appropriate form is the simple, filtered water offering described above.