With increasingly long and intense droughts becoming the norm across Australia, more businesses and homeowners are seeking sustainable water supply solutions. Underground water tanks are growing in popularity as an independent, decentralised way to catch and store rainwater onsite for reuse. The tanks help to alleviate pressure on mains infrastructure and reduce water bills, and for properties with enough rainfall and roof catchment area, installing an underground tank makes economical and eco-friendly sense.
How to Clean Underground Water Tanks
Proper cleaning and maintenance of underground water tanks are essential to keep water reserves pure until use. Over time, contaminants like dirt, leaves and bird droppings can accumulate inside if inlet filters fail, and sediment and sludge settling at the base can breed unhealthy bacteria. As contaminants can build up inside without occasional cleaning to keep the vessels hygienic, they compromise water quality. Thus, regular professional cleaning is recommended for optimal functionality and hygiene, depending on usage and environmental factors.
A thorough professional clean involves:
· Draining and Accessing the Tank
First, all water inside the tank must be drained out via the outlet valve so the interior is accessible, and portable lighting may be required to inspect the entire surface area inside.
· Removing Accumulated Sludge
A suction hose and pump can drain built-up sludge from the tank base containing contaminants and organic debris that has settled over time. The exposed foundation area should then be scrubbed clean.
· Scrubbing Interior Surfaces
Next, the inside walls and floor need scrubbing to remove biofilm residue, algae, dirt, and any surface stains using tank brushes, pads, and hoses for a thorough cleaning to bring the concrete back to its original clean, porous state.
· Structural Inspection
When accessing the tank, its overall condition should be checked for early signs of concrete cracks, water leaks, wall movement or major defects requiring repair. Professionals should also examine the inlet and outlet pipes, joints, bolt points, and entry cover.
· Bacteria Testing
With the interior now drained and scrubbed, water samples can be taken and sent for microbiological testing to check for indicator organisms like E. coli that suggest remaining contamination.
· Controlled Chlorine Disinfection
After cleaning, the tank can be refilled to 20% capacity with clean water and dosed with concentrated chlorine for interior disinfection. Rotating chlorinated water ensures all surfaces are treated to deactivate pathogens. After the appropriate contact time, the chlorinated solution can be flushed out.
The tank is now sterilised and ready to be refilled with fresh rainwater. By scheduling professional cleaning of underground water tanks every 3-5 years, stored water can be maintained at peak quality for safe reuse in non-potable applications.
Complementary Maintenance
To prevent debris and contaminants from accumulating in underground water tanks in the first place, it is helpful to occasionally clean and maintain the roof catchment area feeding the storage system. Ensuring gutters are regularly cleared of leaves and obstructions enables optimal water flow into the tank. Installing gutter guards or mesh covers can also help reduce organic matter washing in.
Consider installing sediment traps, strainers or vortex filters along the pipeline before water enters the tank. These inline pre-filters have finer mesh openings to capture additional sediment, preventing extra build-up inside the reservoir.
Invest in Non-Potent Water Storage
Underground water tanks are an eco-friendly asset to drought-proof businesses and homes against water scarcity and rising supply costs. To discuss maintenance or installing new concrete underwater tanks tailored to your site, consult a qualified water tank supplier today for professional advice and options. Future-proof your property now by capturing and storing rainwater onsite for when you need it most.
