Water Dragons are preyed on in the wild by various snakes, such as Brown Tree Snake (Boiga irregularis), the Common Death Adder (Acanthophis antarcticus), the Lowlands Copperhead (Austrelaps superbus), the Red-bellied Black Snake (Pseudechis porphyriacus) and the Eastern Brown Snake (Pseudonaja textilis). Human introduced animals; cats, dogs and foxes can also cause death and injury to Water Dragons. Predatory birds such as Kookaburras, Butcherbirds and Currawongs are likely to prey on the young hatchlings and small juvenile Water Dragons. Adult Water Dragons have also been known to prey on young hatchlings.
In the Australian National Botanic Gardens the most common predator of Water Dragons is the Eastern Brown Snake. A fence around the Gardens and the front gate attempts to keep out domestic animals.
Another major threat to Water Dragons at the Australian National Botanic Gardens is being run over by cars or vans, and the actions of irresponsible humans.
Water Dragons roam through-out the gardens. They enjoy basking on the bitumen and concrete in the car-parks and roads of the gardens. Unfortunately many Water Dragons get killed by cars or vans in the gardens each year.
Over the years it has been noted by the Gardens staff that the population of the Water Dragons in the Gardens has steadily increased, especially in the Tasmanian Gardens area, which is an ideal habitat for Water Dragons. The Tasmanian Gardens were opened in October 1993. The horticulturalists working in this area have noted in recent years the decline of frog populations in these ponds. They have speculated whether this is due to the ever increasing population of the Water Dragons, as frogs is one of their favourite foods. The drought conditions that Canberra has been experiencing in recent years may also contribute to the decline in the amphibian numbers.