Śrīpāda tīrtham (lit. 'the holy water of the sacred feet') is the water that has washed or touched the feet of a revered divine or human figure — primarily Bhagavān in the arcā form (temple image) or a living Āchārya. In temple worship, the feet of the utsava-mūrti (processional deity) are bathed and the resulting water (caraṇāmṛta) is distributed to devotees, who receive it in their cupped right palm and drink it as a sacrament. This act enacts the theology of śeṣatva: by taking the Lord's feet-water upon one's head and drinking it, the devotee acknowledges and embodies the status of śeṣa (servant) to Bhagavān as śeṣī (Master).
In Śrī Vaiṣṇava practice, the Āchārya's śrīpāda tīrtham holds a particularly exalted status. The Āchārya, being the guru-paramparā's representative and Bhagavān's own instrument, transmits grace through every aspect of his person. Piḷḷai Lokācārya and Maṇavāḷa Māmunigaḷ both teach that the Āchārya's feet are, for the disciple, the functional equivalent of Bhagavān's feet — 'āchāryo hi hariḥ sākṣāt.' Receiving the Āchārya's tīrtham during Pañca-saṃskāra (initiation) or during visits is thus not merely a formality but a sacramental act of grace-reception.
The related concept of nirmalya extends this logic: objects that have touched or been used by Bhagavān (flowers, garlands, food) are prasādam; similarly the Āchārya's śrīpāda tīrtham is treated as nirmalya — something that has been sanctified by contact with the divine. The Āzhvārs themselves model this devotion: Nammāzhvār's yearning to take the Lord's feet-water upon his head runs through the Tiruvāymoḷi as a central image of surrender.