Context. Providing wildlife with supplementary water is a conservation technique that offers an immediate positive impact to animals. However, the potential negative impacts should be assessed.

Aims. We aimed to assess the potential negative effects of water stations on visiting wildlife due to the risk of predation and disease transmission.

Methods. We assessed potential benefits and costs of water supplementation in rural Australia by investigating the behavioural response of animals, at koala (Phascolarctos cinereus) water stations, to weather and to previous visitor species. To determine the risk of disease transmission, water and swab samples were taken from the water stations. Faecal contamination was quantified, and real-time PCR was used to identify various pathogens, including Chlamydia.

Key results. We found that koalas, brushtail possums (Trichosurus vulpecula) and foxes (Vulpes vulpes) responded to hot, dry weather with longer visits to water stations, indicating a benefit of water supplementation to native wildlife, but also to invasive species. Native animals did not alter their behaviour when their visits were preceded by another species, even when this was a potential predator. The presence of pathogens (i.e. Chlamydia and C. perfringens) at the stations did not depend on the number of species that visited but was higher in summer (December to February), representing a potential risk of disease transmission.

Conclusions. Water stations are an effective conservation tool because they can benefit threatened species during hot, dry weather, but there are risks associated with using supplemental water.

Implications. Although potential risks are low, they should still be considered. Efforts should be taken to exclude invasive species and water stations should be cleaned regularly while appropriate personal protective equipment is worn.