Non-revenue water (NRW) in Austria: How is the water infrastructure organized? What damage does NRW cause and what solutions do we offer? We wanted to know this and much more, and asked Thomas Venhoda of the Hawle subsidiary Hawle Service GmbH for an interview:

How is the water infrastructure organized in Austria?

Austria's drinking water supply is traditionally organized on a very small scale. There are 5,500 water suppliers ranging from very small water cooperatives to municipal utilities to large, supra-regional associations. As a rule, a typical Austrian municipality owns and operates its own drinking water supply system. With a total pipeline network of 81,000 km, about 92 % of the population is reached. Another special feature is the fact that no surface water has to be treated. The natural resources used are 100% springs and groundwater bodies, which in most cases require no further treatment apart from preventive UV treatment.

From HSG's perspective, what are the biggest challenges related to "non-revenue water"?

Although we are fortunate to live in a very water-rich country, our water utilities are already facing two challenges in terms of non-revenue water. The first challenge is climate change. Periods of low precipitation are becoming longer and more frequent. Already now, especially regions in the south and east of Austria have historically low groundwater levels. This forces our water suppliers to use the available resources more sparingly. Containing leakage is thus becoming a priority.

The second major challenge is the aging of the pipeline network; in Austria, we have a renewal rate of around 1%, instead of the widely demanded 2%, which corresponds to a useful life of 50 years. If one considers that the damage rate increases exponentially with the age of the pipeline, then it becomes clear that the extended useful life of the pipe infrastructure will only be possible with accompanying, active leak detection and increased selective repair.

HSG stands for service - how often are you called out for "leak detection"?

We are constantly expanding our network of locally stationed service technicians, and more and more regular customers are placing their trust in our expertise. Last year, we were able to locate over 400 leaks with pinpoint accuracy, enabling our customers to remediate them efficiently. There are still a large number of utilities that do not engage in active leak detection but require support in the event of an acute incident.

In this case, it is a matter of quickly localizing a sudden, significant water loss. As a result, we have an increasing number of customers who periodically perform active leak detection. Here, we check every single line kilometer in a defined area. At the highest development stage, we install electronic measuring devices based on IoT and thus realize permanent monitoring, through which even minor leaks are detected immediately.

What methods are used for leak detection?

For providing the services, we use all modern methods available on the market and also develop them further. We have measuring devices based on acoustics. Here, we analyze the propagation of sound, as well as the different travel times of the sound in the pipe material. In the case of plastic pipelines and larger sections on transport pipelines, the helium gas detection method is suitable. Here, small quantities of helium gas are injected during operation and detected with a scanner at the leakage point.
At the beginning of a campaign, it is useful to determine the initial situation, i.e. the leak rate. To do this, we use ultrasonic clamp-on sensors, for example, to measure the system feed-in quantity during the night hours. In relation to the number of house connections, this gives a good picture of the extent of leakage.

What products does HSG use to repair leaks?

We support our customers in finding and precisely locating the damaged areas. The subsequent excavation work, as well as the repair itself, is usually carried out by the waterworks themselves. Of course, our technicians are also available on site to advise on the selection and correct application of the appropriate Hawle products.

Are illegal withdrawals widespread in Austria? Where and how can they be prevented?

Of course, Austrian water suppliers are not happy with unauthorized withdrawals, and there has been a trend to prevent them for some years now. As a rule, it is not about the economic damage caused by the unreported withdrawal of a few m³ of water, but much more about the consequential damage. Hydrants, for example, are not operated properly, are damaged during withdrawal, or are not completely closed so that they freeze up in winter. Of course, the water balance becomes distorted, and there is a risk of contamination if, for example, a safety fitting is not used when hydrants are tapped.
To secure the hydrants, we have developed an electronic solution based on IoT. Through S.CAP, all existing hydrants can be digitized, each activation is registered, the person in charge of the waterworks will optionally receive an immediate notification via SMS.