Commentators have criticized Emoto for insufficient experimental controls, and for not sharing enough details of his approach with the scientific community. In addition, Emoto has been criticized for designing his experiments in ways that leave them open to human error influencing his findings.

In the day-to-day work of his group, the creativity of the photographers rather than the rigor of the experiment is an explicit policy of Emoto. Emoto freely acknowledges that he is not a scientist, and that photographers are instructed to select the most pleasing photographs.

-Wikipedia

Since Dr. Emoto is going it alone he receives much criticism for being a quack selling quackery. For example, the James Randi Educational foundation, an organization that offers a “one-million-dollar prize to anyone who can show, under proper observing conditions, evidence of any paranormal, supernatural, or occult power or event” (Randi, Challenge) has offered to give Dr. Emoto the prize if he will agree “to perform his tests in a double-blind fashion” (Randi, Water), yet Dr. Emoto has not responded.

It is this crucial lack of scientific foundation that prevents Dr. Emoto’s work from attracting interest by widely accepted and respected scientists at long-standing research institutions. This is unfortunate for the world if there is, after all, truth to his claims--as reproduction of his results by any scientist would lend much credence to his work.

...

After the lengthy review of Emoto’s research methods and results, I have come to believe that Dr. Emoto is offering pseudoscience to the masses in the guise of defensible research. Only time and review by others will tell if there is any truth at the heart of Mr. Emoto’s claims, as Emoto himself thoroughly believes in his findings but does not value the scientific method or community. What is truly fearsome is the great numbers of people that accept his words as proven facts without looking deeper to find out if his claims are truly justified.

-Kristopher Setchfield

DR. EMOTO: After the book was published, I was wondering about this, and I came to the realization that these crystals are spirits.

...

In the past 100 years the world's population has increased from 1 billion to 6 billion. During these 100 years, war and capitalism has dominated the planet. Rather than being able to detach from our desires, the opposite has been true. Our desires have grown and grown. Very few people have been able to attain enlightenment in this environment. Few souls have been able to go "home" and I believe they have remained on Earth in the form of water. This connects into the concept of reincarnation, where these spirits keep falling back to Earth and need to redo their lives here.

REIKO: So when a person dies, if they are unable to attain sattori at that time, their soul remains on this planet as water?

DR. EMOTO: That is what I believe, yes. The Japanese character for spirit is a combination of the words "rain" and "soul." People who have seen ghosts report seeing them in water or in places where there is a lot of humidity. It's as if the imprint of the soul, which is in the form of water, suddenly takes form when surrounded by water or moisture -- much like a mirage.

And so, looking at the pictures of the water crystals and the impact they are having, I came to the realization that these themselves are ghosts. Up until now, I had thought of ghosts as something to be frightened of, something that we could do nothing about. But watching these crystals, I realized that by simply projecting beautiful music and words onto them, the crystals or ghosts become beautiful. If that's the case, there's nothing to be frightened of. We need to let everybody know about this, and all use beautiful words and offer beautiful music, and create beauty in the environment.
-From the site linked in the OT.