There is nothing in this world that does not belong to God. Therefore, Qualifying water does not mean that we impart any change in physical properties to water. It means that we understand how each element (in this instance, water) exists as a part of His creation.
Thus, when we go to temple and take theertham – we realise this fact. And for the rest of the day, we remember this fact. Now, every drop of water that goes into your body throughout the day becomes theertham. We will treat water with respect, and never misuse or abuse it.
If every drop we take becomes theertham, then why do we offer it to Deity?
Deity form of God is the most accessible one. Thus, we offer it to that form to tell Him that we realise the fact that everything in the world is His creation and be grateful to Him. Out of love, we add thulasi, cloves and cardamom to the water. Thulasi being fully fragrant from root to leaves indicate complete devotion to God. Cloves and cardamom add fragrance to enhance the joy of serving Him.
– From the discourse of Sri Chinna Jeeyar Swamiji
– 06th Feb, During Initiation Event