230 km of the sewage system renewed


In 2016, 230 of the 37 400 kilometres of the existing sewage pipeline system was renewed, representing 0.62 per cent. Furthermore, 55 per cent of inhabitants were connected to wastewater facilities that complied with treatment permit requirements.


In the perspective of 0.62 per cent renewal of the existing [sewage pipeline system], installation of new sewage pipelines over the same time period constituted 375 kilometres, corresponding to 1.01 per cent. Thus, the rate of installation of new pipelines is significantly faster than renewal; a situation that has remained the same since 2002, when registrations started. Unless renewal rates increase, aging sewage pipelines throughout the municipalities will be the unavoidable result. Even without new installations it will take more than 160 years to renew the whole pipeline system with the current renewal rate.

The age of the sewage pipeline system for the country as a whole has been estimated at around 30 years old (37 years when adjusted for pipelines laid in an unknown period – constituting 17 per cent of the total length). Around 2.2 per cent of the municipal wastewater pipelines were installed before 1940, while 54 per cent were installed in 1980 or later.

Figure 1

Sewage system by timeperiod (2016) and sewage system renewed, 3-year average (2014-2016). The whole country and counties

Highest renewal rates in Oslo, Akershus and Sør-Trøndelag

Renewals tend to vary from one year to another. The key figure “Percentage of total sewage pipeline system renewed, [3-year moving average]” will even out these cyclical variations.

For the period 2014-2016, Oslo and the municipalities in the counties of Akershus and Sør-Trøndelag showed the most renewals on average per year, with 1.66, 0.99 and 0.85 per cent respectively, while Nord-Trøndelag, Sogn og Fjordane and Møre og Romsdal renewed the least, with 0.28, 0.31 and 0.35 per cent respectively.

For the country as a whole, the 3-year-average renewal totalled 0.61 per cent per year, which is around the same level as the single year 2016 estimate of 0.62 per cent.

In 2016, 46 per cent of 415 reporting municipalities reported that they had renewed at least part of the sewage pipeline system, 8 per cent specified zero renewal and the remainder did not respond to that particular question. Corresponding figures on installation of new pipelines were 53 and 20 per cent of the municipalities respectively. In addition to the aforementioned 415 municipalities, there were also 13 municipalities that did not submit the form (“missing respondents”).

Figure 2

Municipality reporting on renewal of wastewater pipelines (per cent) . Country 2012-2016. County 2016

Akershus and Rogaland have the longest pipeline system

Estimations for 2016 show that there were around 37 400 kilometres of municipal sewage pipelines in the whole country (not including separate storm water pipelines), which equals approximately 93 per cent of the circumference of the earth at the equator. The sewage pipelines can be broken down into 7 400 kilometres of combined sewage and storm water and 30 000 kilometres of a separate sewage system.

In addition to the 37 400 kilometres of sewage systems, there are an additional 17 900 kilometres of separate storm water pipelines; in total around 55 300 kilometres of municipal [wastewater pipelines] in Norway.

Figure 3

Length combined system (sewage and storm water), separate sewage and separate storm water. County. 2016

The municipalities in the counties of Akershus and Rogaland have the longest wastewater pipeline systems, while Oslo and the counties in Nordland have the largest percentage of combined sewer systems.

Sewage entering places it does not belong

It has been estimated that around 1 950 [sewage overflows] have taken place throughout the country in 2016. This corresponds to 53 sewage overflows per thousand kilometres of municipal pipeline system – a 10 per cent increase compared to 2015. Sewage overflows may lead to wastewater flowing to the storm water pipeline system and out to recipients or causing damage to buildings or other types of infrastructure. Furthermore, the municipalities have accepted liability for around 285 closed cases of basement flooding in 2016.

55 per cent of “inhabitants” comply with treatment permits

Around 55 per cent of inhabitants connected to a municipal wastewater facility of 50 [population equivalents (pe)] or more were connected to a facility that complied with treatment permit requirements in 2016. This is up 1 percentage point compared to 2015.

Furthermore, there is still a relatively large share of inhabitants – slightly less than 33 per cent – who belong to a group where treatment permits are not complied with. These facilities are both large and small in size, and geographically are scattered throughout the country. Simultaneously, there is also a large remaining share of around 12 per cent where compliance is unknown due to lack of reporting of permits and/or corresponding discharges.

Figure 4

Inhabitants connected to wastewater facility (50 pe or larger) and compliance with treatment permits. County 2016. Country 2013-2016

The purpose of treatment permits is to prevent unwanted effects on the natural environment that receives treated wastewater from wastewater facilities. Treatment permits are issued by the authorities, and are adjusted to the receiving [water recipient] and its sensitivity to pollution. The strictest permits are therefore to be found in areas where pollution loads are already high.

The most common non-compliance is found in relation to phosphorous permits. This is however not surprising since many wastewater facilities have a permit for the discharge of phosphorous. Many facilities also have permits for mechanical treatment, but these facilities are normally smaller in size and less prone to non-compliance.

Income from fees and fee calculation basis almost equal

In 2016, the fee calculation basis per inhabitant was NOK 1650, and the income from fees was NOK 1661. Compared to 2015, the income from fees per inhabitant increased by less than two per cent, while the fee calculation basis per inhabitant increased by nearly four per cent.

More regionally, the highest fee calculation basis per inhabitant and incomes from fees per inhabitants are found in the county of Oppland. On the other side, Oslo shows the lowest fee calculation basis per inhabitant, while Sør-Trøndelag has the lowest income from fee per inhabitant.

Figure 5

Income from fees, fee falculation basis and direct operating expenditures per inhabitant connected to municipal sewage systems. NOK per connected person. 2016

Municipal costs in the water sector are predominantly covered by fees paid by users of the service. Regulations stipulate that fees in the municipal water and wastewater sector cannot exceed the municipality’s actual costs for providing that particular service (“self cost”). Accurately stipulating income from fees to cover the real calculation basis in a single year is complicated. Thus, the municipalities are allowed to decide on fee levels so that income from fees over a five-year period equals the fee calculation basis.

The sum of the fee calculation basis was almost equal to the sum of the income from fees in 2016. This also applies for the period 2012-2016.