A leaking reservoir is not simply another item on an asset maintenance schedule. It is treated drinking water escaping every day from infrastructure designed to protect one of our most important resources.
Every litre stored inside a drinking water reservoir has already been captured, treated, pumped and transported through an extensive network before it reaches storage. Significant investment has already gone into that water through treatment plants, pumping stations, pipelines, reservoirs and the operational systems required to keep communities supplied.
When treated water escapes through a crack, construction joint or deteriorated section of concrete, it is not only water that is being lost. The energy, infrastructure and operational investment behind that water is being lost with it.
For councils, water utilities and asset managers, the challenge is not simply deciding whether a leak should be repaired. The more important question is whether the proposed repair will address the cause of the problem or simply delay its return.
Why Reservoir Leakage Matters Now
Australia’s water infrastructure is under growing pressure, making the condition and performance of existing assets increasingly important.
In Queensland, the Local Government Association of Queensland reported in May 2026 that ageing water and wastewater infrastructure is contributing to a pipe breaking somewhere across the state approximately every 73 minutes. It also reported that the average pipe age is 58 years, with more than half of the network beyond its typical service life.
New South Wales is also showing how much difference proactive leakage management can make. Through the NSW Government’s Regional Leakage Reduction Program, 7.5 billion litres of water had been saved by the end of 2024, with a further four billion litres targeted for saving by the end of 2026.
Climate conditions add another consideration. The Bureau of Meteorology has confirmed El Niño conditions during 2026, with forecasts indicating the event is likely to persist into the latter half of the year. Its August to October outlook also indicates below-average rainfall is likely across large parts of eastern Australia, although conditions and impacts vary by region.
Together, these factors reinforce a simple point. Protecting the water already collected, treated and stored is an important part of protecting the broader network.
Why Reservoirs Begin To Leak
Reservoir leakage can develop for many reasons and the visible point of water loss does not always tell the full story.
Common defects include construction joint failures, concrete shrinkage and movement, cracking, ageing sealants, form tie penetrations, deteriorated waterproofing systems and gradual deterioration of the concrete itself. Initially, these defects may appear relatively minor. A narrow crack or small leaking joint may not seem urgent compared with other capital works competing for attention. However, water will continue to follow available pathways through a structure. Over time, persistent leakage can contribute to deterioration of the surrounding concrete, corrosion of reinforcement and an expanding remediation scope.
This is why investigation matters before treatment begins.
A Reservoir Repair Rarely Follows The Drawings Exactly
A recent WS Remedial Group reservoir remediation project demonstrates the importance of assessing the structure as it actually exists, rather than relying entirely on original documentation.
The reservoir was losing treated water through the wall-to-roof construction joint as well as several internal beam and soffit joints. According to the original drawings, the joints were expected to measure approximately 25 mm. Once our team was on site, most were found to be between 40 and 50 mm.
That difference changed the repair strategy.
Remedial work often presents conditions that could not have been fully anticipated from drawings or previous documentation. Existing structures move, materials deteriorate and original construction can differ from what was documented.
A successful repair therefore requires more than following a specification. It requires understanding the asset in front of you, assessing the actual defect conditions and adapting the repair strategy accordingly.
Treating The Pathway, Not Just The Visible Leak
For this reservoir, the repair strategy focused on preventing stored water from escaping through the affected joints while creating a more continuous barrier within the structure. The wall-to-roof joint and end beams were sealed externally using a potable-water-rated sealant, while internal beam and soffit joints received corresponding treatment.
Following the sealing works, flexible polyurethane resin was injected behind the joint from above the roof slab. This enabled the team to target the water pathway within the structure rather than relying solely on a surface repair. Importantly, much of the work, including the injection process, could be completed without personnel entering the reservoir.
Every step was selected around the actual condition of the asset, the location of the leakage and the requirements of the water-retaining structure.
That distinction matters because repeatedly treating the visible point of leakage without understanding the pathway behind it can lead to recurring maintenance and unnecessary Expenditure.
Knowing When Remediation Is Not Enough
One of the most important findings during the project had little to do with leak sealing itself. During the works, the WS Remedial Group team identified a heavily cracked and spalling concrete beam within the structure.
Although the defect was located within the same reservoir, it extended beyond what could responsibly be addressed as part of remedial leak sealing works alone. The issue was referred back to the client’s structural engineer for further assessment.
This is an important part of responsible remedial work.
The goal should never be to apply a repair simply because the defect is physically accessible. A specialist contractor needs to understand what falls within the repair methodology, recognise when a condition requires structural engineering input and communicate that clearly to the asset owner.
Knowing the limits of a remedial solution can be just as important as knowing how to perform the repair itself.
The Value Of Getting The Repair Right
Behind every reservoir inspection is an individual or team responsible for making decisions about a critical public asset.
For a council asset manager, project manager or water authority engineer, approving remediation is not simply a matter of purchasing maintenance work. It involves determining whether the proposed solution protects the asset, represents responsible expenditure and addresses the defect with the appropriate level of technical understanding.
A well-planned reservoir remediation project should provide confidence that the cause of the leakage has been investigated, the repair method suits the actual defect and asset conditions, issues outside the contractor’s repair scope have been identified and the structure has been treated with its long-term performance in mind.
That confidence is particularly important for water-retaining infrastructure, where the consequence of repeated leakage extends beyond maintenance costs.
Every litre lost has already travelled through the system.
Before Summer Demand Increases
If an asset register includes drinking water reservoirs, concrete water tanks, balancing tanks or other water-retaining structures, the period before peak summer demand presents an opportunity to review their condition.
Small leaks rarely resolve themselves. Early investigation can provide more options for remediation, reduce continued water loss and help prevent relatively contained defects from becoming more extensive repairs.
WS Remedial Group specialises in investigating and remediating leaking reservoirs, potable water tanks and other water-retaining structures throughout Queensland and New South Wales. Our capabilities include leak sealing injection, structural crack injection, concreate remediation, joint refurbishment and waterproofing systems.
Whether the issue is a known leak or an asset that is simply due for inspection, the first step is understanding what is actually happening within the structure.
From there, a more informed decision can be made about the most practical path forward.
Protect the asset. Protect the water.
Repair. Protect. Strengthen.
