9 CFR § 3.10 - Watering.

§ 3.10 Watering.

If potable water is not continually available to the dogs and cats, it must be offered to the dogs and cats as often as necessary to ensure their health and well-being, but not less than twice daily for at least 1 hour each time, unless restricted by the attending veterinarian. Water receptacles must be kept clean and sanitized in accordance with § 3.11(b) of this subpart, and before being used to water a different dog or cat or social grouping of dogs or cats.