We use cookies on this website to collect data about your visit. Third-party cookies, e.g. from social media, will only be stored after your approval.Read more about cookies

Identify sources of water loss

Danish water utilities are among the best in the world at limiting water loss. Learn about the technologies and methods they use to monitor the pipeline grid, plan pipeline repairs, and identify and repair leaks quickly.

Water leak

Denmark has implemented systematic measures to reduce the loss of drinking water as it makes its way from waterworks to the consumer. Danish drinking water providers are actually among the best in the world in this area.

Water loss is a waste of resources

Water loss in Denmark is 7.8 per cent on average. In comparison, many countries lose as much as 30 to 60 per cent of their treated water before it reaches customers. This is not only an enormous waste of clean water, it is also a waste of the resources that have been used to extract the water, treat it and distribute it.

One of the reasons why Denmark is so good at keeping drinking water in the pipeline grid is that providers use new technologies, methods and knowledge. This makes it possible to measure and register water data and to quickly identify even the smallest pipeline leaks.

Another reason is that, since 1994, waterworks with a water loss of more than 10 per cent have been required to pay a penalty fee to the state. Furthermore, since 1996, all properties connected to public water utilities have been required to install water meters. This has resulted in significantly more reliable data on which to base efforts to reduce water loss.

This website provides an description of a number of these methods and technologies. Additionally, there are examples of three water utilities that have succeeded in reducing water loss significantly over the past few years by applying a systematic approach to the issue.


Read more

There are many good reasons to reduce water loss

Overview of methods and technologies

Cases - three examples

What is water loss?

This website defines water loss as the amount of distributed drinking water that does not reach customers, and that water utilities therefore do not receive payment for. This is also known as Non-Revenue Water (NRW). NRW covers:

  • the amount of water lost due to e.g. ruptures and leaks in the pipeline grid and reservoir overflows (also known as physical losses)
  • unauthorised consumption, such as illegal tapping and meter inaccuracies (also known as apparent losses)
  • authorised consumption used to flush pipes at new installations and during repairs, water used for fire fighting and sprinkler systems checks, etc. (also known as unbilled authorised consumption)

Water loss is often either calculated as the percentage of total distribution or as cubic meters per network kilometre per annum. See examples of both types of water loss in the publication ”Water in Figures 2016” (pages 20-21) that includes water-loss calculations from selected Danish drinking water providers.

Denmark among the best in the world

Danish drinking water providers have one of the lowest water-loss rates in the world. This is confirmed by the website www.leakssuite.com, run by one of the world's leading experts on the subject, Allan Lambert, who is part of the Water Loss Specialist Group, International Water Association (IWA). The ranking is based on a comparison of the Infrastructure Leakage Index (ILI) of 36 Danish drinking water providers with a corresponding index for water utilities located outside Denmark.

For more information

You are welcome to contact the organisations below if you would like to know more about specific technologies. They can also help you identify the appropriate advisors and suppliers.

DANVA - stakeholder organisation for drinking water and wastewater utilities as well as all professionals in the field of water and wastewater.

Danish Environmental Technology Association - the sector association for Danish environmental technology companies.

Danske Vandværker - the sector association for Denmark's waterworks.

There are many good reasons to reduce water loss

Since 1994, water utilities in Denmark have paid a penalty fee for any loss of water that exceeds 10 per cent of their total distribution.

This in itself has provided a financial incentive for water utilities to launch efforts to reduce water loss.

Even though a water utility has a water loss of less than 10 per cent, there are still important reasons to limit water loss even more:

  • Water loss is a waste of resources. The loss of drinking water in the pipeline grid is not just a waste of good water. It is also a waste of the energy that was used to produce the drinking water.
  • Better exploitation of groundwater. Pipeline water loss is an unnecessary waste of groundwater resources, which every year cost considerable sums to protect.
  • Risk of contamination. In some areas, water loss will seep back into groundwater aquifers. However, there is a risk that the water will become contaminated underway or end up in a groundwater aquifer that is not used for drinking water.
  • Drinking water leaks into the sewer system. Some of the water loss will leak into sewers or directly into a surface water recipient, which means the water can no longer be used as drinking water. This is particularly serious in areas where the groundwater resource is vulnerable.
  • Image and corporate social responsibility. Water utilities can demonstrate their corporate social responsibility by working proactively with water loss. Their initiatives and results can be reported and referenced in their CSR reports.

Danish Water Sector Reform Act

The Danish water sector is regulated by the Danish Water Sector Reform Act. This Act covers municipal water and wastewater utilities as well as private waterworks that sell more than 200,000 cubic metres of water per year.

The Act requires drinking water and wastewater utilities to collect specific performance parameters, including water loss. Reporting is optional in 2017. However, from 2018, this requirement will apply to all drinking water providers covered by the Danish Water Sector Reform Act.

Read more about the Danish Water Sector Reform Act

Download the Danish EPA's "Vejledning om indberetning til performance-benchmarking"(in Danish only)

Report: Managerial and technological methods to reduce water loss

In 2015, the Danish Nature Agency published a report on managerial and technological methods to reduce water loss at water utilities.

The report presents efforts by 28 Danish water utilities to reduce water loss. The information in the rport was collected through interviews focusing particularly on the managerial and technological tools used by the utilities. The participating utilities are primarily water utilities with distribution of more then 200,000 m³/year.

Download the report "Ledelsesmæssige og teknologiske metoder til reduktion af vandtab” (in Danish only)

Overview of methods and technologies

Water utilities can use methods and technologies such as monitoring, leak detection and compartmentalisation of the pipeline grid to minimise water losses.

Quick repairs of known leaks

Even small leaks should be repaired as quickly as possible. A seemingly small amount of water at surface level can be indicative of a larger leak at the source.

Proactive replacement of problematic pipeline sections

In areas with a documented high frequency of ruptures, or where there are other known sources of water wastage (e.g. drilling saddles in aluminum or old iron pipes), the best solution will often be to replace the water pipes. The immediate costs of this could soon be recuperated by expenditure saved on emergency repairs and on the waste of water and resources.

Monitoring night-time consumption

For most waterworks, monitoring the distributed water volume between 02:00-04:00 hours could indicate whether there is a leak in the supply zone. Distribution during this period will vary from utility to utility. However, collecting and comparing distribution data will make it easier to assess whether there is a leak.

Systematic leak detection

It can be a good idea to carry out regular leak detection searches, even if the night-time consumption does not indicate any leakage problems. Modern search devices can locate leaks before they become bigger and more serious. The devices range from simple listening rods, correlation or area surveillance to the construction of permanent monitoring systems.

Compartmentalisation of pipeline grids

The supply area can be split into sections. This makes it possible to monitor water flow into a specific area. The values measured between 02:00-04:00 hours will provide the best indication of leakages. By using a log function, data can then be collected and analysed.

Global water loss - Danish solutions with LEAKman

LEAKman is a beacon project under MUDP (Environmental Technology Development and Demonstration Programme) which was granted DKK 43 million in the autumn of 2015. The purpose of the LEAKman project is to present Danish solutions to reducing clean drinking water losses, and to pave the way for new Danish water technology.

Follow the project at leakmanagement.net

What technologies are available?

Leak monitoring

  • An  SRO system is a digital system designed to manage, regulate and monitor a facility. Some SRO systems contain a module that collects detailed online flow data. The module can then be used to detect and locate leaks, plan repairs and raise an alarm in the event of significant changes to water consumption.
  • Model-based leak detection is an advanced method by which continuous pressure and flow readings are validated by a mathematical model. The mathematical model can be statistics-based and will alert users if there are any deviations from the norm in a section of the pipeline grid.
  • Leak detection can be carried out using technologies such as  tracer gas and acoustic equipment. Acoustic equipment consists of either mobile units or fixed units installed in the pipeline grid. There are many varieties of acoustic equipment, depending on the material that the leak stems from.

Leak detection

Source: The report "Ledelsesmæssige og teknologiske metoder til reduktion af vandtab” (only in Danish)

Water meters installed at waterworks and consumers can be inaccurate. Among other things, this inaccuracy depends on the type of meter and the physical installation. Meter inaccuracy can result in readings that are either too high or too low.

Monitoring exit meters at waterworks

In order to register real water loss, it is vital that the exit meters at waterworks are accurate. For example, if a meter reading is 2 per cent too high, the waterworks will suffer considerable additional costs if water wastage is already more than or close to 10 per cent. The inaccuracy can be due to the type of meter, the manufacturer, the age of the meter, dimensioning or incorrect installation on the pipes.

Recommendation

Even the best meters will not be accurate if the fitting instructions are not followed. There are usually requirements regarding the dimensions and length of the pipe immediately before and after the meter. The type of meter and the manufacturer can also influence the accuracy throughout the measurement area. Even though there are no requirements regarding the age of a meter, it may be a good idea to replace meters at regular intervals. Alternatively, meters can be sent for testing and adjustment in order to ensure - and document - that the meter is accurate.

Consumption meters

All consumption meters are subject to a guideline on control systems for cold and hot water meters in operation (”Måleteknisk vejledning om kontrolsystem for koldt- og varmtvandsmålere i drift” - in Danish only). This guideline states that all meters must be approved and tested or replaced in accordance with relevant guidelines.

However, errors can still occur during the meter-installation period. for example the meter can stop registering. If the error is not detected, the lack of charges will increase water loss.

Recommendation

It is important to monitor and react to unusually low water consumption, which typically becomes apparent in connection with the annual meter reading. Some newer meters have built-in technology that notifies waterworks automatically if the meter stops working. In this situation, immediate follow-up is required to avoid the lack of metering being registered as water loss.

Placement of consumption meters

The waterworks distribution grid usually stops at the boundary of a property. At this point, the waterworks branch pipe is connected to the property's underground service pipe. The coupling point often consists of a branch pipe valve or a meter well. However, if waterworks meters are located in the building itself, then a leak in the underground service pipe will usually result in an increased water-loss rate for the waterworks. If the leak is detected, the owners of the property have to carry out the necessary repairs or replacement at their own expense.

Recommendation

Leakage from private underground service pipes can effect water-loss rates at waterworks. To avoid this, waterworks can place a water meter in a well at the border of the property. If the meter is placed at a border, a leak in the underground pipe will be detected much quicker than if the meter is placed in the building. This also means that any water loss due to leakage can be invoiced.

Meter reading frequency

Consumption meters are normally read once a year. If a property's water installation has a leak, a high volume of water might be from when the leak first occurs to when it is detected and stopped. If water wastage is registered, waterworks will usually only receive payment corresponding to "normal" consumption + 300m3. Moreover, this is a waste of resources and an unnecessary expense for the consumer.

Recommendation

New meter technology makes it possible to read meters more frequently. This means that leaks can be detected earlier. The same applies to the underground service pipe if the meter is placed in a well at the border of the property.

One important factor in reducing water loss is renovating pipes before leaks occur. The quality of the renovation is also important to prevent new leaks.

Old iron pipes

Since 1970, waterworks in Denmark have mainly used PE and PVC pipes in their pipeline grids, but private underground service pipes have also used iron pipes. Depending on local soil conditions, iron pipes are susceptible to corrosion and leaks. This means that iron pipes must be monitored closely to avoid water loss.

Recommendation

Iron pipes can be monitored effectively by placing water meters at the border of a property. Additionally, iron pipeline sections should be more closely monitored using acoustic leak detectors, pressure tests or via monitoring wells.

Asbestos pipes

Asbestos pipes do not rust. However, they are vulnerable to subsidence. This means that the pipes might rupture and require emergency repairs. Handling asbestos pipes requires great care as the dust from the pipes is dangerous to inhale.

Recommendation

Sections with asbestos pipes with many cracks should be replaced by pipes made of a different material. This will limit water loss and simultaneously cut operating costs in connection with emergency pipe repairs.

Aluminum tapping saddles

During the 1960s and 1970s, poor-quality aluminum tapping saddles were fitted to Danish pipeline grids.

The problems became apparent 10 to 15 years later. Today, better quality saddles are used, but the old aluminum saddles are still causing problems. In addition to water loss, waterworks are burdened by emergency excavation requirements outside of normal working hours.

Recommendation

If the locations of the old tapping saddles are known, waterworks should consider replacing them to avoid leakage. In addition to limiting water wastage until the leak appears at the surface, the individual cost per tapping saddle replaced will be significantly reduced.

Assembly errors

Errors can occur when laying new water pipes. These errors might not be discovered before the pipes are buried. Such errors can result in leaks that are not immediately detected because new water pipes are often placed in draining materials that delay signs of leaks on the surface. A leak could therefore remain undetected for many years and cause significant water loss.

Recommendation

The number of errors can be reduced by combining staff and external-contractor training with quality control and supervision during and after completion of the work. The price of pipeline work is important, but it is not more important than quality. Over the pipe's operational life of 75 years, a loss of only 1 liter per minute will result in total water wastage of 40,000 cubic meters.

Excavation damage

Each year, excavation damage causes pipe ruptures and other damage to water pipes. This damage is usually repaired quickly, but sometimes the damage is not detected or not reported to the waterworks.

Work is carried out blind during controlled under-drilling since it is based on maps and test boreholes. Severe damage to a water pipe will cause a rupture that will require immediate repair. Less serious damage to a water pipe might cause a leak which might not be detected from the surface or via the borehole.

Recommendation

The risk of damaging water pipes can be reduced by thorough preparation beforehand. Among other things, this will require procuring up-to-date maps and clearing known pipes. A dialogue with local pipeline experts can also be an important part of these preparations.

Private underground service pipes

Water loss from private underground service pipes can account for a large percentage of a waterworks' water loss. The reason for this is a combination of smaller pipe dimensions and a short distance to the drain. This means that water wastage does not always become visible at ground level.

Recommendation

The underground service pipe can be monitored if a meter well is installed at the border of the property. Any possible waste of water resources will be registered and payment can be charged, either in part or in full. If fitting a meter well is not an option, then leaks can be detected via systematic pressure tests or leak detection on the underground service pipes.

Flushing water pipes

The water used to flush water pipes will always be included with water loss. If the flush speed is too high or if it goes on longer than necessary, then this will result in unnecessary water loss.

Recommendation

Water wastage can be reduced by optimising flush speeds and durations. This will save both resources and energy. Flush speeds should normally not exceed 0.5 meters a second and flushing should only last until the pipes are clean. This can be checked by taking a water sample. Flushing should be stopped or reduced until the results of the analysis are ready.

Water used for fire-fighting benefits society and should therefore not be included as water loss. Waterworks should therefore enter into agreements with municipalities that water usage in connection with fire fighting and tests must be reported. Furthermore, fire hydrants should regularly be checked for leakage.

Fire hydrant leakage

Fire hydrants -particularly older ones - sometimes leak slightly after use or testing. Dripping fire hydrants can waster up to 10 liters an hour. This corresponds to an annual 87 cubic meters of water wastage.

Recommendation

Waterworks should routinely consider the fire hydrants in their area and possibly inspect them at least once a year. Waterworks should also have a written agreement with the municipality regarding receiving immediate notice if the municipality discovers a leaking hydrant. In cases of water wastage, the fire hydrant should be repaired, replaced or shut down permanently as fast as possible.

Fire-fighting consumption

Large amounts of water are sometimes used in connection with fire fighting. In order to put out a fire, easy access to the required amount of water is clearly vital. If the amount of water used is not reported to the waterworks afterwards, then it will be registered as water wastage, which is not the case.

Recommendation

Waterworks themselves should note incidents requiring the use of fire hydrants. Waterworks should also enter into a written agreement with the municipality that they will register and notify water consumption in connection with fire fighting. Waterworks will also be able to assess the water consumption themselves by reviewing the amount of water distributed on the day in question. The water consumption can also be read accurately at the waterworks' SRO installation. If the municipality is subsequently billed for the amount of water used, then this will not effect the water-loss rate.

Theft and other unauthorised usage

Unauthorised tapping of water from fire hydrants sometimes occurs. This may be vandalism or simply theft. It can also be a matter of ignorance if a contractor acutely needs water for his asphalt cutter or cement mixer. This is naturally completely unacceptable and should be considered theft. In addition to water wastage, this also results in wear to the fire hydrant and the risk of incorrect use which may result in damage to the fire hydrant.

Recommendation

Possibly in collaboration with the municipality, the waterworks can send a letter or flyer to all local builders and contractors on the rules for fire hydrant use. This should state that unauthorised use of water from fire hydrants will be considered theft. It is also a good idea to inform citizens living in the supply area of the rules.

Consumption in connection with fire hydrant testing

Most municipalities regularly test the performance of their fire hydrants as it is important to ensure that they can supply the required amount of water in an emergency.

Recommendation

Waterworks should have a written agreement with the municipality regarding how often fire hydrants are tested. Waterworks should be informed of the amount of water used during routine flushing. If the municipality is subsequently billed for the amount of water used, then this will not effect the water wastage rate.

Water for building sites

Water consumption at a building site can fluctuate from zero to several hundred cubic meters. Many price lists charge for a fixed number of cubic meters for building water. If the consumed volume of building water exceeds the charged amount, then this amount will be registered as water loss. If water consumption at a building site is not measured, then there is little incentive to avoid water wastage during the building period.

Recommendation

Water consumption at both small and large building sites should be measured and charged as far as possible. It is therefore recommended that a metering point be located at the entrance to the building site, so that all water consumption during the building period can be charged. Before the water is opened, a written agreement should be made with the project developer, stating that payment can be charged in advance.

Unauthorised use of hoses

Hoses reels/fire alarm boxes are often fitted at businesses, institutions and larger housing units. Hose reels are sometimes used for other purposes than extinguishing fires or testing. Since the water used for fire extinguishing is not measured, this use will effect the wastage rate of waterworks and result in lost revenue.

Recommendation

Facilities with hose reels should have their own independent pipeline grid without a meter and it must be easy to access and use. By securing the box or hose nozzle with an easy-to-break seal, with regular inspection the waterworks can make sure that they are not being misused. There should be clear signs stating that the hose reel can only be used to extinguish fires and that the waterworks must be contacted immediately if a seal has been broken.

Theft before meters

Intentional tapping of non-metered water should be considered theft. The tapped amount of water will effect the water-loss rate and result in a financial loss for the waterworks’ consumers. Unintentional tapping before meters is also unacceptable and should therefore be invoiced retrospectively based on estimates by the waterworks.

Recommendation

In addition to general information for consumers and local plumbers, the waterworks themselves should also keep an eye out for anything unusual.

Personnel from waterworks and external fitters and plumbers should report abnormalities or suspicions of fraud that they observe in connection with replacing meters.

It may be related to a missing or defective seal on the water meter or tapping components located between the meter and the distribution pipe.

Cases - three examples

Preventing water loss is a shared issue at Halsnæs Forsyning

By compartmentalising the pipeline grid, as well as through other measures, Halsnæs Forsyning has been able to reduce water loss by 12 per cent in only two years. Now it’s all about keeping losses down.

Halsnæs Forsyning controls about 200 kilometers of distribution pipes and produces 630,000 cubic meters of clean drinking water a year for 5,000 properties.

Water loss

When a new metering system was taken into use in 2010, it became clear that water loss was higher than originally assumed. A 20 per cent water loss was measured in 2013.

Compartmentalisation was the answer

Therefore, Halsnæs Forsyning commenced systematic efforts to reduce water loss. The water utility began compartmentalising the pipeline grid in 2011, and several monitoring wells were fitted to measure flow and collect data.

These efforts continued during the following years, and today 25 monitoring wells are in place that regularly transmit data back to headquarters so that it is possible to react swiftly to the worst leaks.

Data was initially dealt with manually in Excel files. However, this soon proved to be far too burdensome and resource-demanding. Therefore, the utility invested in a new system that was able to receive, process and provide graphic illustrations of water loss, flows and pressure in the individual sections.

A 12 per cent reduction in two years

All in all, these efforts resulted in an 8 per cent decrease in water loss by the end of 2015, or what corresponds to a water-loss reduction of 12 per cent in only two years.

The reduction has resulted in considerable annual savings. Moreover, the system has not resulted in more excavation work than earlier. Excavation is now carried out in the right places and with greater precision than previously.

Increased ownership among employees

In addition to the reduction of water loss and the financial savings, as well as the release of personnel resources, since data no longer needs to be processed manually, these initiatives have also resulted in improved focus and ownership among employees.

Billede af arbejdet på Halsnæs Forsyning

This is primarily because the new system is relatively simple and easy to work with, and employees are able to gain an overview of the supply area on the big touch screen in the control room. Leakage monitoring has therefore become a shared issue: something everyone takes an interest in and can monitor on a daily basis.

In general, the transition has been a learning process that has provided many new insights. For example, it was an eye-opener that even the smallest cracks in pipes can result in significant amounts of water loss.

From cure to prevention

The first objective of a water loss below 10 per cent was reached in 2015. The next objective for Halsnæs Forsyning was to maintain water loss at comfortably below 10 per cent in order to avoid paying penalty fees to the state.

In connection with this, the task was to calculate and assess how much water loss Halsnæs Forsyning could accept in the future, as well as where and how to apply resources in order to secure a satisfactory return on investment. Now it is clear that new procedures must be developed in order to maintain focus on water loss. Furthermore, a better overview of the condition of sections of the pipeline grid is required.

Further information

Mikkel Nielsen, head of water and heating
Tel.: +45 47 76 07 00
Direct Tel.: +45 20 46 74 68

Copenhagen isn’t leaking

HOFOR (Greater Copenhagen Utility) is the result of a merger between Copenhagen Energy and the water utilities in Albertslund, Brøndby, Dragør, Herlev, Hvidovre, Rødovre and Vallensbæk municipalities.

Every year, HOFOR distributes 52 million cubic meters of water to 1 million customers and manages 14 waterworks and more than 4,000 kilometres of water and wastewater pipelines.

Water loss

HOFOR's water loss was previously at 9 per cent, but is now down to 5 per cent. 

Area surveys every three years

A close eye - not to mention ear - is kept on leakages in water pipes in HOFOR's supply area. HOFOR has divided the City of Copenhagen into 76 map areas. These areas are surveyed at three-year intervals. The seven other municipalities under HOFOR follow the same three-year cycle.

Area surveys are carried out by allocating an employee to each of the 76 areas. The task for each employee is to go out and check the section valves marked on the map. While doing so, the employee will listen to the valves and make a note if they hear something that might indicate a leak nearby.

Once the next valves have been inspected, the employee will return to the noise for a closer listen. This time, the employee will also listen to the stopcock in order to ascertain whether the noise stems from private land.

The next step is to pinpoint the leak by using correlation: Two acoustic leak correlators are placed along the stretch of pipe where there is a suspected leak. Finally, a subsurface acoustic sensor is used to register any noise made by small rocks and other materials clattering near the leak. The results are then compared to the results of the correlation. The excavation point can now be marked and a contractor can be called in.

Pressure and flow meters instead of compartmentalisation

While surrounding municipalities have been compartmentalised, HOFOR has investigated whether it would make sense to compartmentalise the pipeline grid of the City of Copenhagen. It was assessed that doing so would jeopardise the water supply to the many industrial businesses, as well as sprinkler and fire-fighting systems in the city. Instead, 24 meters have been fitted so that HOFOR can constantly monitor pressure and flows in different parts of the pipeline grid and react to any abnormal changes.

Focus on particularly vulnerable areas

HOFOR has special focuss on certain areas of Copenhagen. These include the cobbled streets and roads in Østerbro. Large leaks will most often be visible at ground level. However, if a leak occurs here, the material below the cobbles will be swept away and the cobbles will become lodged together. At some point cave-in when someone drives or walks across the surface.

In order to keep abreast of leaks in particularly vulnerable areas, HOFOR selects a larger area and erects 20-25 noise loggers. After 48 hours, the data will be collected and plotted onto a map. A blue label on the map indicates that the noise logger did not register anything unusual. A red label indicates that the noise logger has registered a sound nearby. After this, personnel are dispatched to inspect the area using correlation and subsurface acoustic sensors.

HOFOR ascribes much of its success at keeping water loss to a minimum to its personnel in the field. HOFOR management has prioritised employee training so that personnel have the correct tools and allocate sufficient time to search for leaks. This has had a positive derivative effect on employee commitment.

Billede af vandpyt

Permanent noise logger trials

For a number of years, on a trial basis, HOFOR has had permanent noise loggers installed in a large area of Brønshøj. The loggers relayed data to small units installed in lampposts that then forwarded the data. No leaks had been ascertained prior to launch of the project. However, just two days in, the system had already detected a leak. Instead of immediately repairing the leak, the leak was left for a week in order to ascertain the extent of water loss from this isolated leak.

It turned out that this one leak could have cost HOFOR DKK 2.1 million in lost water sales if it had gone undetected for three years. During the five-year test project, which cost DKK 1.5 million, 8-10 similar leaks were discovered, some of which were located on private property.

Although the project proved that a system of permanent loggers would be profitable, it was concluded that operating the system, including purchasing and replacing batteries, would be too cost-intensive to be sustainable.


The project also proved that a quicker reaction time meant fewer restoration costs. The aim is to dig dry holes!

Inspecting water mains from the inside

It is one thing to monitor and detect leaks in the pipeline grid on a daily basis. It is something else to inspect the four large water mains (90 kilometers in total) which convey drinking water from the waterworks to the supply areas. The condition of these pipes is hard to check, and inspecting them is not as straightforward as for other types of pipe.

Therefore, in the autumn of 2015, HOFOR tested a new technology that is particularly suitable for inspections of long drinking water pipelines. A small ball equipped with advanced technology and an acoustic censor is sent into the pipeline from the waterworks. The ball flows with the water and is picked up again further down the pipe. A status report is generated based on the data collected by the ball, and possible leaks are identified within a distance of two meters.

HOFOR identified four leaks using this technology. One of the leaks was repaired, and experts considered whether it was worthwhile doing something about the remaining three. Digging-up one of these leaks revealed that it would only result in 3 liters of water loss per day, compared to the 25 million cubic meters that HOFOR distributes to the people of Copenhagen annually.

Further information

Ole Skytte, head of section
Tel.:+45 30 10 64 42

Kim Roar Nielsen, team leader
Tel.:+45 30 10 64 41

Water loss on Djurs at an all-time low

Effective technologies, an updated database on ruptures, and a long-term and flexible renovation plan are keeping water loss at a minimum at Vandcenter Djurs.

Since 2005, Vandcenter Djurs has been run as an independent water utility (a.m.b.a.). Until 2012, the water utility was named GAV (Grenaa & Anholt Vandforsyning). In connection with its name change to Vandcenter Djurs, the accounts of the two utilities were consolidated into one.

Vandcenter Djurs distributes 1.40 million cubic meters (2015) a year and is one of the largest consumer-owned water utility companies in the Danish waterworks association, Danske Vandværker. The water utility has a 320-kilometer-long pipeline grid and supplies clean drinking water to about 15,900 consumers in the supply area.

Water loss

Vandcenter Djurs reduced its water loss from 9.85 per cent in 2009 to just less tha 5 per cent in 2015. The water-loss rate varies from year to year and, among other things, depends on how much water is used annually to flush new pipes before they are taken into use.

Even the smallest leaks are found in time

The supply area is divided into sections from which online flows are measured regularly. The system is operated by an SRO installation, eight section wells and manual main valves.

Measuring and comparing consumption between the hours of 02:00 and 04:00; hours during which neither consumers nor industries use a lot of water, provides technicians with a good basis for identifying leaks.

Even a slight water consumption increase of 1 cubic meter per hour will be detected by employees at the utility. Compartmentalisation of the pipeline grid means that it is possible to separate sections and examine whether the increased consumption continues. This methodrepeated until it reaches street level, after which identifying the leak becomes possible by using a subsurface acoustic sensor, for example.

Texting consumers

The supply area of Vandcenter Djurs is characterised by a catchment area of several small cities and villages. If increased water consumption is identified in a pipe supplying one of these areas, then it is likely that the leakage stems from a private installation.

To avoid sending out a crew immediately, Vandcenter Djurs uses a system that sends a text to residents in the area. The text message encourages consumers to report back if their water meters are moving despite no water being consumed. This system cuts costs for the water utility and is a service to private consumers as they are made aware of a leak and can quickly begin repairs.

Systematic renovation plan

The renovation of Vandcenter Djur's pipeline grid follows a long-term plan divided into four-year intervals. The plan expires in 2097 and is based on the age of the grid and on the materials it is made of. The first part of the plan is to phase out iron pipes and then pipes made of PVC. On average, 4-5 kilometres of pipes are renovated each year in the supply area. However, the plan is not static. The Vandcenter Djurs rupture database is an important tool in this context. All ruptures are registered and categorised and the system can identify good and poorer sections of the pipeline. If data shows several leaks within the same section over a short period of time, then that pipeline will become a priority, even if, according to the plan, it is not schedule to be renovated until much later. The renovation plan is therefore updated once a year on the basis of the incidents identified in the rupture database.

What is the end goal?

The board at Vandcenter Djurs have a clearly stated aim to be a responsible utility supply company and they believe that clean drinking water is a resource that must be protected by efficient operation. This means setting realistic objectives with regard to what is an acceptable amount of water loss.

In 2014, Vandcenter Djurs had a water loss of only 2.9 per cent. However, such low water loss is close to the limit of what is financially viable. At this point, the resources needed to limit water loss - including wages - begin to exceed the costs of producing and distributing the water.

Further information

Henrik Harregaard Jordalen, CEO
Tel.:+45 87 58 21 55