SuttaCentral
There was a Bhikkhu from Burma who would bless water. As a result, people would get healed from it, and even protected from harm. It was also claimed that this Monk was an Arahant.
Question: Does such practices violate any rules of the Patimokka? Would an [Arahant] take to doing such things; even if it benefits humans?
Use of blessed water is, in certain contexts, compatible with monastic practice. It would be important to see if the monk in question follows procedures found in the texts, is generally disciplined, promotes right view, and makes an effort to avoid fueling rumors that heās an arahant. If these points are there, then itās quite likely that the practice heās using is legitimate.
Translatorās note:
Buddha delivered this Jewel Discourse (Ratana sutta[1]) to the Venerable Ananda, and gave him instructions as to how he should tour the city with the Licchavi citizens reciting the discourse as a mark of protection to the people of Vesali. The Venerable Ananda followed the instructions, and sprinkled the sanctified water from the Buddhaās own alms bowl. As a consequence the evil spirits were exorcised, the pestilence subsided. Thereafter the Venerable Ananda returned with the citizens of Vesali to the Public hall where the Buddha and his disciples had assembled awaiting his arrival. There the Buddha recited the same Jewel Discourse to the gathering.
PS: I didnāt saw that the question was directed to the bhikkus, sorry.
As an aside some Thai bhikkus seem to provide a āblessingā like this without getting unwanted miraculous projections:
Blessing" A monk was spraying blessed water to a faithful family.
For Westerners religious similarities are striking:
modernized update 
I heard Ajahn Brahm tell a story about a Thai woman who was really sick with cancer so she asked Ajahn for some holy water each week. She then started asking for more. Like a 10L bucket of it. Ajahn thought maybe she was taking a bath in it or something and kept making it. But one day he got a call at the monastery asking how much to buy some holy water. He said he didnāt sell it. The person on the other end of the phone then commented that it canāt be the real deal because he was buying it from this thai woman for $10 for 100ml, but that it was āreally good stuffā. After that he stopped making it in quantity and you have to go and be sprinkled by him.
Maybe I havenāt got the story quite right and Ajahn Brahmali can fill in the details.
To answer the question, maybe Bhikkhuni PÄcittiya 49 would possibly fit the bill.
Ajahn Brahmali just translates it as āworldly artsā but I learned it originally as things like magic. I think this is also in the khandakas as a dukata for bhikkhus. However, the khandakas are not in the patimokha, so the above bhikkhuni rule might be the only one which is a pÄtimokkha rule
In DN2 under the Long Section on Ethics there is a whole list of āmagic and magic adjacentā things which we shouldnāt do, but I canāt actually see holy water.
Claims about arahantship are notoriously unreliable. Everyone wants to think of their teacher as an arahant, but the evidence is normally flimsy, at best. Even if a teacher makes an outright claim to arahantship, there is usually no good reason to take this at face value. Arahants would be expected not to make such claims. A nice example of how arahants declare their realisation - and this only to their teacher, usually the Buddha - is found in the Khema Sutta at AN 6.59:
And then, soon after Khema and Sumana had left, the Buddha addressed the mendicants: āMendicants, this is how gentlemen declare enlightenment. The goal is spoken of, but the self is not involved."
Atha kho bhagavÄ acirapakkantesu Äyasmante ca kheme Äyasmante ca sumane bhikkhÅ« Ämantesi: āevaį¹ kho, bhikkhave, kulaputtÄ aƱƱaį¹ byÄkaronti. Attho ca vutto attÄ ca anupanÄ«to.
And in the Soį¹a Sutta at AN 6.55, Soį¹a expresses his awakening as follows:
When a mendicantās mind is rightly freed like this, even if compelling sights come into the range of vision they donāt overcome their mind. The mind remains untainted. It is steady, imperturbable, observing disappearance. Even if compelling sounds ā¦ smells ā¦ tastes ā¦ touches ā¦ and ideas come into the range of the mind they donāt overcome the mind. The mind remains untainted. It is steady, imperturbable, observing disappearance.
Suppose there was a mountain that was one solid mass of rock, without cracks or holes. Even if violent storms were to blow up out of the east, the west, the north, and the south, they couldnāt make it shake or rock or tremble.
And yes, if a monk or nun declares that they are an arahant it would be a PÄtimokkha offence, either a pÄrÄjika if they are lying or a pÄcittiya if it is true. It hard to imagine an arahant would deliberately commit an offence against the monastic rules.
As to the water blessing itself, it is not inconceivable it might have some effect. Apart from the placebo effect, which is certainly real, it seems clear enough from the suttas that a powerful mind can affect the external environment, including other people. For instance, there are examples of protective verses and verses used to heal sickness, such as the famous bojjhaį¹ ga paritta at SN 46.14, SN 46.15, and SN 46.16.
I think it is possible for arahants to use water blessings, at least occasionally, as seems to have been the case with Ajahn Chah, whether he was an arahant or not.
Yes, thatās how it goes!
