Share thisBoth the Animal Welfare Act (AWA) and the Guide for the Care and Use of Laboratory Animals (The Guide) cite “potable” and “ uncontaminated” as the essential criteria for drinking water provided to laboratory animals.
Admittedly, these are rather broad definitions, and considering that most modern animal facilities have available water consisting of a wide range of qualities, decisions regarding the nature of the water provided within facilities becomes somewhat challenging Production of each type of water carries varying costs in materials, waste, and technical expertise. Furthermore, options for delivery to the “end user”, i.e., the animal, vary from intracage bags and gel to attached prefilled bottles of a variety of types, to sophisticated labyrinths of pipes and manifolds interconnecting terminal intracage devices and racks to reservoirs or supplies of variously prepared waters. The ramifications of the broadly accepted definition of “water” can be quite serious. Construction, operation and maintenance costs, staffing needs, and replacement expenses are impacted by delivery preferences. Investigators will frequently impact decisions with particular needs or requirements. Herein, we discuss the wide variety of water qualities currently available for use in facilities throughout the country and the two major types of water delivery methods for mice and rats: automated delivery systems and bottles, their costs, and impacts on vivarium design.
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Types of Water
To begin with, raw water, or that which is supplied to the facility, likely comes from a general pumping station or treatment plant within municipal sources. It may be post-treated within a parent institution’s facilities plants, but will have a certain quality. This is considered “incoming” water. It may not always be a stable source. Municipalities, regardless of size, will frequently have multiple sources for the incoming water. These may be wells, reservoirs, springs, lakes, etc., and may vary by season or supply limitations. Treatment by an institution will normally result in a range of “waters” available internally for distribution/use, identified as softened, de-ionized, filtered and reverse osmosis, polished or unpolished. Not all these methods of treatment affect the quality and condition of the incoming water in the same way. Common contaminants are listed in Table 1. Some treatments remove particulate or dissolved contaminants that others do not. Incoming water may be treated by the municipality with fluorides, chlorides, and chloramines. There will be acceptable limits of microbial contaminants. Illustrated in Figure 1 are the relative sizes of typical contaminants and the filtration necessary to exclude them. It should be noted that ion exchange (de-ionized) and softening columns do not exclude bio-contaminants.