Tanks -
22 February 2023
Under House Water Tanks
High-Quality Australian under house water tank with a strong, lightweight, space efficient and tucked away out of sight. View our Downunda underground tank range today, and don’t forget that these tanks come with the following;
Key Features;
- ISO9001:2015 Certified
- 10-Year Full Warranty
- 1 Piece Mould
- UV Stabilised
- Available in a full range of contemporary Colourbond® colours

Underground Water Tanks
Underground water tanks provide hidden rainwater storage for properties where above-ground space is limited or visual impact needs to be kept to a minimum.
Part of our complete rainwater tank range, these below-ground systems are ideal for urban homes, landscaped gardens and modern developments. You can also explore slimline tanks and compact water tanks for space-saving above-ground alternatives.
Why Choose Underground Water Tanks?
Hidden Water Storage That Preserves Outdoor Space
Below-ground rainwater tanks are installed beneath lawns, driveways and landscaped areas, allowing you to store significant volumes of water without sacrificing valuable outdoor space.
Ideal for Homes and Sustainable Developments
These systems are commonly used for household rainwater supply, garden irrigation and environmentally conscious building projects where appearance and space efficiency are important.
Engineered for Long-Term Underground Use
Tankworld underground systems are built from durable materials designed to withstand Australian conditions and provide dependable performance for many years.
Australian Water Storage Expertise Since 1972
With over 50 years of experience, Tankworld supplies reliable rainwater storage solutions across New South Wales, Victoria and South Australia.
The 5000-litre water storage capacity of the Downunda makes it the perfect underground water tank for your development. If you have an issue with your small block and need to place a water tank underground or under your home, the Downunda is the best option.