A water dragon enclosure should generally be fairly large and lined with a substrate that is safe for use with reptiles. Wooden enclosures are often considered best, since water dragons may head-butt their reflections in the sides of a glass enclosure, and can injure themselves badly in doing so. The ideal water dragon enclosure typically has a warm area for basking, and a cool area where the dragon can retreat if it feels too warm. For dragons that do not have access to natural sunlight, a UVB lamp will generally be necessary. The water dragon enclosure will also need a large water dish, and will need to be kept relatively humid for the dragon's health.
It is generally believed that water dragons need a lot of room in which to thrive. The typical water dragon enclosure should generally be about 6 feet (1.8 meters) long, about 4 feet (1.2 meters) high and about 3 feet (0.9 meters) deep. The cage should normally be kept at temperatures between 84 and 88 degrees Fahrenheit (28.9 to 31.1 C) during the day. At night, the water dragon enclosure should usually be kept at temperatures between 75 and 80 degrees Fahrenheit (23.9 to 26.7 C). One side of the cage should generally be kept cooler than the other, since these reptiles need to be able to warm or cool themselves by changing their environment.
Water dragons are generally believed to benefit most from exposure to 12 hours of natural sunlight each day. Since most owners can't offer this much access to natural sunlight, a UVB light for the tank is generally recommended. UVB rays are believed necessary for these reptiles to produce vitamin D, without which they may succumb to a life-threatening calcium deficiency. The light should be allowed to shine into the enclosure unobstructed by glass, plastic, or wire mesh, since these things can block the UVB rays. Most experts recommend changing UVB bulbs every six months, to ensure that they are still functioning properly.
These exotic pets usually like to bathe, and will generally need a large pool within their enclosure. There should generally be enough water in this pool to come halfway up the dragon's body when it gets in. The water will typically need to be changed, and its container disinfected, each day. The entire water dragon enclosure should usually be misted twice daily to maintain an appropriate level of humidity, which is normally about 80%. A substrate of disinfected soil can help retain humidity within the enclosure, and lizard-safe plants can help create a more enriching, stimulating environment for the water dragon.
Other good substrates for a water dragon enclosure are said to include strips of cotton fabric, newspaper, paper towels, and orchid potting soil. Substrates with small chunks that could be swallowed should generally be avoided.