Water restriction/deprivation protocols involving animals are often necessary for behavioral training. Because these protocols have the potential for causing significant distress to the animal, the Animal Research Committee (ARC) has established the following guidelines.

  • The least restriction that will achieve the scientific objective should be used. In the case of conditioned-response research protocols, use of a highly preferred fluid as positive reinforcement, instead of restriction, is recommended.
  • Due to individual species and strain variations in water requirements, average guidelines for water intake or urine output are not appropriate.
  • Every protocol involving water restriction in non-human primates should be individually evaluated. In general, any non-human primate given less than 80 ml/kg/day is considered water restricted. Primates are not allowed less than 22 ml/kg/day. Protocols involving water restriction in primates must be discussed with a DLAM veterinarian. The monitoring schedule and criteria for suspension of water restriction established by the veterinarian must be followed at all times.
  • Water restricted/deprived animals—regardless of species—must be monitored daily for continued good health as judged by stability of performance in the experimental protocol, development of signs of dehydration (skin turgor, mucous membrane dryness, urine output and specific gravity, blood analysis), and development of signs of stress. Weight must be recorded at least weekly, and more often for animals requiring greater restriction; records on body weight must be kept. Animals must not lose body weight in excess of the limit indicated in the approved protocol. In general, the ARC limits weight loss to 20% unless scientific justification is approved by the ARC for exception to this policy. Disturbances in normal behavior and activities can signal stress, including changes in normal sleep cycles, abnormal social interactions, and emergence of abnormal behaviors such as thumb sucking, cage chewing, hair picking, abnormal vocalizations, and aggression. Careful evaluation of the animal for physiologic signs of dehydration should be performed should signs of stress become evident.
  • Investigators utilizing water restriction/deprivation protocols must communicate with the animal care staff. To prevent animals from receiving improper rations, the staff must be informed about periods of restriction/deprivation and about rest periods when full or supplemental water can be provided. To communicate to the veterinary and animal care staff during periods of water restriction/deprivation, special treatment cards must be placed on the cage indicating that the investigator’s laboratory will be responsible for watering animals, and the duration (start and end dates) for this special watering schedule must be noted on the card. Special treatment cards may be obtained from DLAM; please consult with them as to the proper card(s) to use and the information they must contain.
  • The above policy does not apply to water restriction prior to surgery or anesthesia. It is typically not necessary to water-restrict an animal prior to surgery or anesthesia, except for non-human primates. It is essential that pigs NOT be water restricted at any time. For consultation on water restriction or deprivation prior to surgery or anesthesia, please consult with a DLAM veterinarian.


  1. Guide for the Care and Use of Laboratory Animals. National Research Council, pp. 30-31, 2010.
  2. Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research. National Research Council, pp. 49-61, 2003.
  3. Orlans, F.B. Prolonged water deprivation: A case study in decision making by an IACUC. Institute of Laboratory Animal Resources (ILAR) News, Vol. 33, pp 48-52, 1991.
  4. Desimone, R., C. Olson, and R. Erickson. The controlled water access paradigm. ILAR News, Vol. 34, pp 27-29, 1992.
  5. Hughes, J.E., et al. Health effects of water restriction to motivate lever pressing in rats. Laboratory Animal Science, Vol. 44, pp 135-140, 1994.

Approved 11/13/00; Revised 1/28/02, 7/26/04, 7/26/10, 5/18/20; Updated 1/18/11, 7/26/19