Rainwater tanks can provide an excellent habitat for mosquito’s to breed in. In addition to causing nuisance, certain types of mosquito can be vectors for virus. This is more of an issue in the Sydney and Illawarra Regions with Ross River and Barmah Forest viruses reported to be transported by the mosquitos. The symptoms of these viruses are mainly rheumatic affecting the joints and presenting flu like symptoms.
Mosquito borne disease may become more common in Australia due to rising temperatures and humidity associated with climate change. The Australian Department of Health provides an additional guide to rain water tanks with information on mosquitos in sub-tropical areas of Australia.
By far the preferred approach for managing mosquitoes and other insects is to keep them out of tanks. In addition, rainwater should not be allowed to pool in containers or on surfaces below tank outlets or taps, as this can also provide a breeding site.
Unless in use, all access points excluding the inlet and any overflows should be kept shut and close fitting removable lids or screens fitted.
Tanks water should be inspected for the presence of mosquito larvae (wrigglers).
Further information on preventing mosquitos can be found in the Guidance Manual for the Design and Installation of Urban Roofwater Systems in Australia.
Guidance Manual For The Design and Installation of Urban Roofwater Harvesting Systems In Australia Edition 1(PDF, 1MB)