With leak detection technology developing rapidly with increasing benefits, many large utilities do not have the internal expertise in the technologies most appropriate for monitoring their system. Water Utilities and the Institutions that manage them are largely governed by the perception of, and attitudes to, leakage and water misuse. Leakage in distribution systems is a major problem for water utilities throughout the world, in both wealthy and developing nations. Water distribution pipes in many industrialized countries are approaching the end of their useful life and many governmental agencies within their respective countries have declared that the replacement or rehabilitation of water distribution and transmission systems is one of their country’s biggest infrastructure needs. Leakage rates of 10-20% are considered normal in the US, but the aging infrastructure in some areas can be losing up to 45% of water distributed. In developing regions such as Latin American and in countries such as India, Non-revenue water (NRW) is estimated at 40%, due to aging pipes, poor network design and construction, damage to exposed pipes, and leakage at poorly sealed connections. NRW must be measured in the amount of water wasted as well as the amount of energy expended and extrapolating to provide annual megawatts worth of water pump usage wasted and millions of gallons of water lost.
Utilities and governmental organizations should work with solution providers that have an established track record and are innovating advanced leak detection technology. This will provide the owner with accurate failure points via non-destructive methods, assess current pipe conditions and detail specifics of the need and solution during budget requests/expenditures for the costly pipe repairs; this is often the failure point in many Water Loss Management Programs. Any data gathered during leak surveys must provide information that is particularly valuable to utilities in managing their most critical large diameter in-grounds assets. However, previous methods and monitoring practices provided data that was static and only provided a point-in-time snapshot of the transmission main system. This lack of continuous data represents an unacceptable level of operational risk for large-diameter transmission main failure, as it is costly and includes flooding, property damage, insurance claims, service disruption, and reputation damage. It is clear that utilities demand actionable information about their critical transmission mains in a timely manner, yet are highly sensitive to financial and logistics constraints.
Non-revenue water (NRW) typically consists of three categories:
- Unbilled authorized consumption, this usually makes up a small fraction of NRW
- Apparent losses; this includes illegal connections, meter inaccuracies that can account for a sizeable percentage of NRW
- Real losses; this consists of any water that is physically lost from the system before it reaches a consumer’s water meter, with a vast majority due to leakage in the system
Non-Revenue Water – Leak Detection Technologies
Older technologies in practice include acoustic (ground microphones, acoustic loggers on pipe fittings, and tethered in-line leak detectors), infra-red thermography, chemical tracer, and mechanical methods.
Emerging technologies include ground penetrating radar (GPR), combined acoustic logger and leak noise correlators, digital correlators, and radio-frequency interferometers and un-tethered leak detection. Advanced signal processing and acoustics sensor design locates very silent leaks; added automatic noise filtering and velocity calculator allows high accuracy in pinpointing leaks on any material of pipe or multiple pipe types. The addition of PC-based software and streamlined graphical user interfaces on many newer systems optimizes operator experience and confidence to determine leak position.
Before implementing any leak management, detection and repair program, a water audit should be performed to quantify leakage and prioritize water loss actions. Water Audits are typically conducted by monitoring water inputs, flow throughout the distribution system, pressure management and usage during low-flow periods; this data is used to quantify losses and identify zones with high leakage. The data quality must be that which provides confidence in the audit results, as this permits utilities to understand the nature and extent of its water losses and select the best water loss reduction strategy.
Three key items
- Smart Systems – Use smart systems, smart sensors and software for predicting and continuously monitoring leakage
- Material and Technology – Utilize continually improving pipe material and pipe installation technologies to minimize leakage
- Pressure Optimization – Optimize pressure management areas and implement SCADA systems to continuously monitor water losses in real time
Financial Aspect of Water Loss Management
The costs of leak management, detection and timely repair programs include staff training, management, labor, materials and equipment. These costs are generally recovered through reduced water loss, reduced maintenance costs, lower probability of catastrophic failures and confirmation that pipes are in good condition thus preventing premature pipe replacement.
With increasing populations and income growth, piped water to homes around the world is growing and needed for positive gains in health and development. As the per capita demand for water increases rapidly during this evolution; water resources are becoming increasingly stressed, which can eventually encumber economic development. Leak management, detection and repair programs in water systems are a significant part of an overall comprehensive strategy to reduce strain on existing water resources.
Accounting for water and minimizing water loss are critical functions for any water utility that wants to be sustainable. Demand-side strategies must be part of the tools used to reduce demand, such as Water rates that escalate as more water is used and encouraging consumers through consumer rebates and education programs to install water-efficient products and efficiency practices.
Within water utilities, an organizational culture of water conservation and financial sustainability will motivate employees, customers and community at large to help reduce leakage and waste. When water conservation is seen as a priority by the population, particularly under water stress or during drought, politicians progressively are made aware of the possible water savings and will better respond to funding leak management and repair programs. The opportunities from leak management, detection and repair programs provide economic benefits that often outweigh the costs, when implemented appropriately.