Yes, you can use regular tap water to grow garlic in water. Here are a few tips: Use lukewarm tap water, not cold water straight from the tap. The garlic cloves prefer slightly warmer water.
Pour the water into the container until it reaches about 1/2 to 1 inch deep, just enough to cover the bottom of the garlic cloves. Avoid submerging the entire clove in water.
Change the water every 2-3 days, or whenever it starts to look cloudy or discolored. Stagnant water can lead to mold and rot.
Make sure to remove the garlic cloves before changing the water to avoid damaging the roots.
Use a clean glass jar, bowl or cup to grow the garlic in. Plastic bottles can work too.
The key is to keep the water fresh and at the right level. Tap water is fine, but avoid using distilled or purified water which lacks the minerals garlic needs.
With regular water changes, your garlic cloves should sprout healthy roots and green shoots using just tap water.