Water meters

Requirements apply to water meters during use, not only at the point of sale. The Norwegian Metrology Service supervises that users – most often municipalities – have an internal control system in place to ensure compliance.

Internal control

The requirements for water meters are based on the principle that the user must have internal control of their meters. This internal control must ensure, among other things, that the meters are suitable, correctly installed, and within the regulation’s requirements for maximum permissible error. Central to internal control is a metrological self-check of water meters used for financial settlement.

Where conditions permit, the Norwegian Metrology Service recommends that this self-check be carried out as a sample-based inspection. This method involves dividing all the user’s meters into groups with meters of the same type, installation period, and similar operating conditions. A random selection of a certain number of meters from each group is then inspected. The results of each sample inspection are considered representative for the respective group of meters.

The Norwegian Metrology Service recommends that a group of meters undergo a sample inspection no later than 8 years after the first meter in the group was installed. The number of meters to be inspected depends on the total number in the group and the meter size. Sample-based inspection is resource-efficient, as only a proportion of meters are checked after 8 years, and the result of this inspection is assumed to apply to all meters in the group.

Self-check or use of external parties

When water meters are inspected, this must be done using reference equipment and methods that ensure sufficient traceability to the International System of Units (SI).

For water meters, the meter may either be sent to a laboratory, or a simplified metrological inspection (a type of simplified calibration) can be carried out on-site where the meter is installed.

The user of water meters is free to carry out this simplified metrological inspection themselves, provided they have sufficient competence, prepare proper procedures, and acquire reference equipment calibrated with traceability to the SI. The regulation does not set definitive requirements for how inspections must be carried out, only that the inspection must help ensure that the user’s meters comply with the regulations.

It is also the user’s responsibility to ensure that, if external companies are used for meter inspections, these have sufficient competence. Proof of competence may, for example, be accreditation for calibration of water meters. The Norwegian Metrology Service has no approval scheme for companies, but may, if necessary, request to carry out a voluntary audit of companies performing tasks related to water meters. Justervesenet may also, if necessary, issue individual decisions requiring such external service providers to implement their own internal control for measuring instruments and measurements.

Do you need documented verification of your measuring instruments – at a time that suits you?

The Norwegian Metrology Service offers on-request verification as one of our services. As a neutral third party, we can carry out verification and in-use inspections and issue documentation. We have the equipment and expertise to help your enterprise meet the requirements for measurements.

Frequently asked questions

Which measuring instruments are subject to surveillance? 

All measuring instruments used for financial settlement in trade and industry – for example, scales, fuel dispensers, and water meters – are subject to supervision.

Does surveillance involve costs? 

Many of the Norwegian Metrology Service’s supervision areas are financed via annual fees paid by the relevant industry. Other actors will receive an invoice after supervision. You can find pricing information here.

What does the Norwegian Metrology Service check during surveillance of water meters? 

We supervise that municipalities’ internal control systems for water meters meet the metrological requirements of the regulation.

How are summons, decisions and receipts from the Norwegian Metrology Service sent? 

In connection with supervision of measuring instruments, the Norwegian Metrology Service sends summons, decisions and receipts digitally via Altinn. This follows from the Digitalisation Circular (Digitaliseringsrundskrivet), which requires businesses to receive digital correspondence from public authorities.

How do I find correspondence from the Norwegian Metrology Service in Altinn?

Select the correct enterprise/profile when logging in to Altinn, in the top right corner.
Check that you have the role “Post/Archive” for the enterprise you represent.
Look in folders such as “Archived” and “Deleted messages” – the correspondence may have been moved.
If you still cannot find the correspondence, contact Altinn user service:
- Telephone: 75 00 60 00
- www.altinn.no

How to find letters sent before 2025 in Altinn

If you cannot find letters from the Norwegian Metrology Service (Justervesenet) that were sent before 2025, they may be located in the “old Altinn”.

Altinn user support informs us that the documents should be available to users with the correct access rights.

If you need assistance, you can contact Altinn by phone at +47 75 00 60 00, by email, or via their website.

What must I do after a supervision? 

If nonconformities are found, you will receive guidance on what must be corrected, a deadline for remediation, and information on any fees.

What happens during a supervision? 

Supervision may involve checking the measuring instrument or the measurement process, providing information on correct use, and guidance on the regulations. After supervision, the enterprise receives a report or a decision.

Why does the Norwegian Metrology Service carry out supervision of measuring instruments? 

Supervision ensures that measuring instruments used in trade and industry provide correct and fair measurements – for the benefit of both consumers and businesses.