With the climate change and dramatic temperature increase over past years, our water consumption will rise too. We will need much more water for agricultural purposes and for everyday life. Water will undoubtedly be a valuable resource in the future that should not be wasted. Yet our water saving capabilities are far from appropriate numbers.

According to recent study from International Water Association (IWA) we lose globally about 346 million cubic metres per day or 126 billion cubic metres per year in water distribution systems on the way to consumers. Such losses are called Non-revenue water or NRW and are equivalent to approximately USD 39 billion per year as the average water cost.

NRW means water that has been produced and is "lost" before it reaches the customer. Basically, all water was not billed. If we will have a look on the standard water balance introduced by IWA, it can be clearly seen what is considered as Non-revenue water:

• Unbilled authorized consumption – the water that was free distributed for example for firefighting, public fountains or provided to public institutions for free.
   
• Apparent losses – the result of unauthorized water consumption such as theft and water metering inaccuracies.
   
• Real losses – they can also be considered as technical losses, are the type that can occur at mains, service reservoirs and service connections up to the point of customer metering. Typical losses can be leaks, bursts, overflows, etc.

It may be surprising that fully 25% of all water fed into the network is never billed. Some of this non-revenue water (NRW) is used by the suppliers themselves to flush pipes and similar tasks, and some of it goes to tasks like fire-fighting free of charge. By far the most of it, however, is lost to pipe leaks.

Such huge variations are dependant from many factors:

• improper management of water distribution systems,
• low awareness regarding the NRW therefore no regulations,
• the usage of low-quality infrastructure components such as pipes, joints, valves etc.

Leakage can’t be prevented entirely, but it can be minimized by investing in the infrastructure. This goes to explain the NRW range in Europe - from 5% in the Netherlands to over 60% in Bulgaria. Bulgaria, however, is currently also the most active in curbing these water losses, renewing 3% of its entire network annually - ten times the rate of 0.3% in Austria.

Typically water losses are associated with numerous problems:

• Extra energy expenses:
  A high amount of lost water means that utilities need to transport greater volumes of water than the customer needs.

• Damages:
  Leakages can cause environmental impact, for example, soil movement or flood. If they will not be noticed on time subsequent soil collapse may become a threat to infrastructure and safety of people.
   
• Additional treatment costs:
  A considerable amount of lost water would flow into the wastewater collection system, adding up to the second round of expensive treatment without providing any customer benefits.

At the same time non-revenue water reduction programs could have the following benefits for water supply operators:

• The consumption of water resources in the utility will be reduced, increasing the working capacities of the utility.
   
• The energy consumption will be reduced as less water will be needed to extract.
   
• Smaller amount of leakages will decrease the load on sewage systems thus decreasing costs for treatment.
   
• Fewer leakages in pipes – less chances of water contamination.
   

A proper strategy of NRW-reduction can improve efficiency of water utilities, extending the lifespan and increasing the profitability of water supply companies in a sustainable way.

Water supply network replacement and maintenance

Water losses often represent a sufficient part of the NRW and are often caused by inadequate maintenance of the distribution network. In many European countries the infrastructure has come to an end of its lifespan, causing numerous water breaks and leaks. For this reason, timely pipeline rehabilitation and replacement are crucial to ensure smooth operation of the entire water supply network.

When it comes to replacing or renovating water networks, one thing is clear: one cannot save on components, such as pipes, valves, joints and fittings, etc. Using high-quality materials can not only sufficiently extend the operation life of the water distribution system, but also reduce its cost of ownership. A sufficient amount of maintenance & repair costs are going to excavation works, downtime costs & penalties, labour, electricity etc. High-quality components fail less frequently and have longer warranty, meaning significant cost savings in longer perspective. All valves produced by Hawle undergo strict quality control and their design life goes beyond 100 years.

Water network monitoring

The NRW reduction strategy requires an efficient leakage detection system. The digitalization of water distribution monitoring system with electronic water meters, sensors and data collection will provide a constantly updating overview and can significantly improve the detection time of leakages and allocation of them. Additionally, the digitalization of hydrants will help to detect if the hydrant was damaged or activated whether itr was authorized usage or not.

Pressure management

The Pressure management strategy is considered to be one of the most popular for increasing the efficiency of water utility by reducing water losses. In 2015 the European Union Comission established document “Good Practices on Leakage Management” where the implementation of Pressure Management is described step by step as well as its profits for stakeholders and best practices.

Non-revenue water problem is becoming more serious each year. It is in our hands to control how much water we do not waste. The sustainable solution for NRW reduction will be an implementation of proper strategy of pressure and NRW management, increasing the potential lifespan of water utilities by using quality products, maintenance strategies, and digitalized water monitoring systems. In the next article we will focus on the problem of water leaks and pipe repair solutions.