Why would an animal need clean water at all?
Water is a basic biological requirement, not a human invention. One paper describes water as the basic need of every individual on earth, whether plant, animal, or human, and says plants and animals require water regularly for growth and development [5]. The same paper notes that human uses go well beyond drinking, including cooking, bathing, and washing, but it does not treat those uses as proof that only humans need water [5].
The farm-animal review points to the same biological dependence in livestock. It frames water as biologically important for farm animals and discusses how much water they require and how they use it [2]. In other words, the need for water is shared; the open question is how strict the "clean" part is across species.
What the livestock evidence actually says about clean water
The clearest animal-specific signal in the supplied evidence comes from the farm-animal review. It notes that some animals require high amounts of water because of milk production, and that layer hens also require high and clean water [2]. That is a direct statement that at least some non-human animals need clean water, not merely water of any quality.
The scope matters here. This is a review of water requirements and utilization in farm animals, so it speaks to managed livestock rather than to every wild species [2]. It also does not compare animals with humans, so it cannot by itself tell us whether human needs are unusual in kind or only in scale. What it does establish is that the claim "only humans require clean water" does not hold for the animals it covers.
Why most of the research is about people
Four of the five supplied papers focus on human water quality and access. One examines clean water as a fundamental part of human survival and health, listing diseases such as diarrhea, cholera, dysentery, typhoid, and skin disease that can follow unsafe water [1]. Another reports that, as of 2020, about 2 billion people lacked safely managed drinking water, and that safely managed water should carry no detectable pathogens such as E. coli or coliforms [4]. A third studies water quality in Bima City, where biological testing found that 12 of 31 samples failed total-coliform requirements and 3 showed E. coli [3].
This human-centered literature explains why the question feels human-centered: the health burden of unsafe water is documented in detail for people [1][4]. But that documentation is not evidence of exclusivity. The same papers do not compare human requirements with those of other animals [1][3][4], so they cannot support the idea that clean water is a uniquely human need.
Does "clean" mean the same thing for a person and a hen?
The supplied evidence does not settle that. For humans, one paper describes clean water as needing to meet physical, chemical, and bacteriological parameters [1], while another sets a strict standard of no detectable potential pathogens in safely managed drinking water [4]. The farm-animal review refers to layer hens needing "clean" water without defining the standard in the abstract [2]. So the shared word may hide different thresholds.
What can be said is narrower and more useful: the need for water is clearly shared across plants, animals, and humans [5], and at least some farm animals are described as needing clean water [2]. Whether every animal needs water as free of pathogens as human drinking-water standards demand is not answered by these papers. The honest answer to the original question is therefore no, humans are not the only animals requiring clean water, but the comparative science of how clean is clean enough across species remains largely unaddressed in this evidence.
Sources used in this answer
Efforts To Improve Clean Water Quality To Support Community Health
Clean water is described as fundamental to human survival and health, with unsafe water linked to diseases such as diarrhea, cholera, dysentery, typhoid, and skin disease, but the paper does not compare human and animal water needs.
Review on water requirement and utilization in farm animal
A review of farm-animal water requirements reports that some livestock, including animals producing milk and layer hens, require high amounts of water, and that layer hens require clean water.
Clean Water Quality Study in Bima City
In Bima City, physical and most chemical water-quality measures met standards, but 12 of 31 samples failed total-coliform requirements and 3 showed E. coli.
Clean water for all
As of 2020, about 2 billion people lacked safely managed drinking water, and safely managed water is defined as containing no detectable pathogens such as E. coli or coliforms.
Water: Lifeblood of every civilization
Water is described as a basic need for plants, animals, and humans alike, with plants and animals requiring water regularly for growth and development.