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- The number of waterworks that deliver satisfactory drinking water has increased considerably over the last 20 years.
- Approximately 90 per cent of the population (4.6 million) receive water from waterworks that must be approved and are registered in the Waterworks Register at the Norwegian Institute of Public Health
- We have insufficient information about private wells and other small water plants that do not require approval plants. These supply water to approximately 525,000 inhabitants.
- In 2016 there were 3,800 repairs to leaking drinking water pipelines. These fractures increase the risk of gastrointestinal diseases.
- The problem with contaminated drinking water is likely to increase for years to come if old pipelines are not repaired or replaced at a faster rate.
Waterworks in Norway - status and trends
Norway has access to good water sources that can be protected against pollution. The level of pollutants, pesticides, heavy metals and other unwanted substances in water is low.
There are two groups of waterworks:
1. Waterworks that supply at least 50 people
These waterworks must be approved by the Norwegian Food Safety Authority. The waterworks can be municipal, intermunicipal or private. In total, 1,500 plants are registered in Norway, and these are included in the water statistics (NIPH, 2016a). The reports show that most supply good quality water.
The Norwegian Food Safety Authority collects water data annually via the MATS system. Data about the waterworks that require approval are recorded in the Waterworks Register at the Norwegian Institute of Public Health.
2. Smaller waterworks and individual supplies that deliver drinking water to less than 50 people
These waterworks do not need approval. In total, these small waterworks supply water to approximately 525,000 people (about 10 per cent of the population). We do not have an overview of the quality of these water treatment plants.
9 out of 10 obtain water from a waterwork that requires approval
In 2014, 90 per cent of the inhabitants in Norway (equivalent to 4.6 million people) received drinking water from one of the 1500 waterworks that require approval (NIPH, 2016a). 10 per cent of the supply came from surface water basins and 90 per cent of supplies from lakes, ponds, streams and brooks.
In some cases, groundwater may be hygienically safe but water from surface water basins must always be disinfected. By 2015, only 2,000 inhabitants in Norway received undisinfected water from surface water basins, from a total of approximately 15 waterworks. See Figure 1.
Improvements over the last 20-30 years
Water treatment plants in Norway have improved over the last 20-30 years. In the period 1995-2001, the effects of the national programme for water supply were particularly visible, where there was an economic investment to improve waterworks.
At the start of the programme, about 1,000 waterworks did not meet the requirements of the current drinking water regulations (Ministry of Health and Care Services, Regulations on water supply and drinking water, No. 68 I-9/95). These waterworks supplied 1.3 million people in Norway. Over six years, water supplies from 350 water treatment plants improved, supplying 800,000 people.
Figure 1 shows that the number of waterworks that supply undisinfected surface water has sharply reduced since 1994. The decline was particularly high up to and including 2001. Since then, there has been an even decline in the number of waterworks that do not disinfect water.
Figure 1: Trend figures for waterworks and for people without disinfected surface water in the period 1994-2015. The figure applies to water waterworks that require approval. In addition, about 10 per cent of the population receives water of unknown quality from waterworks that do not require approval. Source: Norwegian Institute of Public Health (NIPH, 2014, 2016a).
Many old water pipes
Even if the water treatment plants have improved, the pipeline network is vulnerable. One fifth of the pipeline network was built shortly after the Second World War. Experience from municipalities suggests that the pipelines laid during this period have more fractures than pipes laid in other periods.
- In 2016, about 3,800 leak repairs were reported (Statistics Norway, 2016).
- The proportion of pipelines that have been replaced, both now and in the last three-year period are about 0.7 per cent for the country as a whole, but there may be large variations between municipalities.
- At the current rate of replacement, it is estimated to take about 145 years before all pipelines are improved to a satisfactory quality.
County differences in Norway
In Norway, the quality of drinking water (from waterworks that require approval) is measured by checking whether residents in the municipality receive water from a waterwork that supplies safe drinking water. Indicators of safe drinking water are the prevalence of E. coli bacteria in the water and delivery stability.
Drinking water supplies are considered "good" if no E.coli bacteria have been detected in the drinking water for at least 95 per cent of 12 or more samples and that there are less than 30 minutes of non-planned interruptions to the water supply per year.
There is a difference between counties when it comes to the quality of Norwegian water supply.
Figure 2 shows a geographical overview of the proportion of population in the county who have a good drinking water supply. This means that they receive drinking water of good hygienic quality from a waterwork that requires approval and that delivery stability is good. The figure also shows the proportion of people receiving water from such plants.
According to these criteria, more than 92 percent of Norway's population has a good water supply.
Figure 2: The proportion of population receiving water from a waterwork that requires approval (green) and the proportion that have good drinking water supply through such a waterwork (yellow colour). "Good drinking water supply" means that the drinking water of good hygienic quality is supplied by a waterwork that requires approval and that delivery stability is good. Source: Norwegian Institute of Public Health, Municipal Health Statistics.
Oslo, Telemark and Aust-Agder are the counties where the highest proportion of people have a good drinking water supply.
Oppland, and Sogn and Fjordane are the counties where the largest proportion of people receive drinking water from small, unapproved water treatment plants or from wells and other simple water supplies.
Bacterial contamination of drinking water can cause gastrointestinal diseases
Even if the quality of the drinking water is generally good, water supplies in Norway have particular challenges as we have a widespread supply with many small waterworks, extensive use of surface water and a need to upgrade old, deteriorating pipeline networks.
We have little information about how many in total who become ill from contaminated drinking water but some large outbreaks have been registered.
Since 2000, we have had two major disease outbreaks caused by drinking water:
- Giardia outbreak in Bergen in 2004 with about 6000 cases
- Campylobacter outbreak in Røros in 2007 with about 1500 cases.
In addition, there have been a variable number of small outbreaks caused by drinking water from single-use facilities or small communal supplies. During the period 2003-2012, there were 28 such outbreaks registered, with 8060 patients in total (Guzman-Herrador, 2016). In the period 2011-2015, 13 outbreaks were recorded with a total of 248 cases (NIPH, 2016b).
See the section Food and waterborne infections.
Excessive fluoride and radon in some areas
In some areas, fluoride and radon are present in high concentrations in the groundwater. Therefore, some groundwater wells for single-family and small communal facilities have high values of radon and / or fluoride. We do not have an overview of how many are affected.
Drinking water with excessive radon levels can contaminate indoor air and should be aired to release any radon gas before bringing it into the house. Radon is associated with an increased risk of lung cancer.
High levels of fluoride in drinking water may affect the development of teeth, so do not use affected drinking water for cooking or drinking by infants and pregnant women.
Deteriorating pipelines are a major problem
The pipeline system is where water supplies are vulnerable. About a third of all water leaks before it reaches consumers, which is much greater than in most comparable countries.
Since the drinking water pipeline usually lies in the same ditch as the drainage pipeline, which also leaks, there is a high risk of contamination during leakage or repairs. When the pressure in the water pipeline falls, drainage water that is contaminated by sewage can be sucked into the drinking water pipeline. In Canada, it has been shown that around 14 to 40 per cent of all cases of gastrointestinal disease occurred from this type of problem (Payment, 1997).
The rate of replacement and repair of poor pipelines is so slow that the problem of contaminated drinking water is likely to increase in years to come. In addition, large amounts of precipitation and the risk of flooding and landslides as a result of climate change will increase the risk of damage to pipelines. For various reasons, no outbreaks of disease caused by deteriorating pipelines are confirmed but research has shown that there a high prevalence of acute gastrointestinal disease after temporary drops in water pressure (Nygard, 2007).
New studies will map the situation
In order to get a good overview of how drinking water contributes to disease in Norway, the Norwegian Institute of Public Health will carry out a study to investigate the relationship between water consumption and gastroenteritis in a selection of the Norwegian population. This will be done by telephone interviews, online questionnaires and a monthly SMS survey over the course of a year.
The Norwegian Institute of Public Health has also received support from the Research Council of Norway for the project "Effect of climate change on the association between extreme weather events and waterborne disease". The project will examine the association between extreme weather, hydrology and raw and clean water quality at selected water treatment plants. We will also be able to see how robust the water treatment plants are to cope with climate change.
New regulations and preparedness service
New drinking water regulations were introduced in January 2017. The regulations require safe delivery of adequate amounts of safe drinking water. The water must be clear and without any odour, taste or colour. The new regulations can help secure drinking water supplies through more stringent requirements for the operation and maintenance of the pipeline network.
In January 2017, the Norwegian Institute of Public Health established a 24-hour advice service. If acute incidents threaten the water supply, this service will provide advice and assistance to the waterworks.
The advice will prioritise assessments of infection risk from microbiological contamination and acute health hazards from chemical pollutants. Support from personnel with experience from water treatment plant operation and emergency preparedness will also be available. The service can gather experiences that can be used to further strengthen safety at Norwegian water treatment plants.
WATER IN NATURE IS NOT ALWAYS SAFE
Tularaemia (rabbit fever) is a disease that can be transmitted by water. This is especially true in "lemming years" when many rodents die in nature. Another potential source of infection for tularaemia is well water, for example at cabins, where water is unprotected against rodent contamination and is not disinfected.
Contaminated drinking water is one of the most important causes of poor health worldwide. The UN has estimated that about 663 million people lack access to safe drinking water and that 2.3 billion people have inadequate sanitation. WHO estimates that 842,000 people die annually from diarrhoea as a result of unsafe drinking water and poor hygiene and sanitation. Over 40 per cent of cases involve children under the age of 5 years, equivalent to about 1,000 deaths daily (WHO, 2016a).
In Europe alone, 62 million people live in a house without a direct water supply. It is assumed that there are 14 deaths in the WHO's Europe region daily as a consequence of unsafe drinking water and poor hygiene and sanitation (WHO, 2016b).
Guzman-Herrador, B., de Blasio, B. F., Lund, V., MacDonald, E., Vold, L., Wahl, E., et al. (2016). Vannbårne utbrudd i Norge i perioden 2003 –12. Tidsskr Nor Laegeforen, 136(7), 612-616.
NIPH (2014). Vannrapport 121: Rapport fra Vannverksregisteret – Drikkevannsstatus (data 2009 and 2010) [Report].
NIPH (2016a). Vannrapport 124: Drikkevann. Rapport til Mattilsynet 2016 [Report].
NIPH (2016b). Utbrudd av smittsomme sykdommer i Norge i 2015: Vevbasert system for utbruddsvarsling (Vesuv) (Årsrapport) [Report].
Nygard, K., Wahl, E., Krogh, T., Tveit, O. A., Bohleng, E., Tverdal, A., et al. (2007). Breaks and maintenance work in the water distribution systems and gastrointestinal illness: a cohort study. Int J Epidemiol, 36(4), 873-880.
Payment, P., Siemiatycki, J., Richardson, L., Renaud, G., Franco, E., & Prevost, M. (1997). A prospective epidemiological study of gastrointestinal health effects due to the consumption of drinking water. International Journal of Environmental Health Research, 7(1), 5-31.
Statistics Norway (2016). Kommunal vannforsyning 2015. [website]. Extracted 20th June 2016.
WHO (2016a). Drinking-water Fact Sheet. [web document]. World Health Organization. Extracted 27th January 2017.
WHO. (2016b). Water and sanitation. [Nettside]. Copenhagen, Denmark: World Health Organization. Extracted 27th January 2017.