Utility meters 

Under trade measurement laws, specified electricity and water meters used for trade (bill for usage) must be:

• pattern approved
• verified.

You use a meter for trade if you use the measurement to determine the amount to pay for a transaction, even proportionally.

Pattern approval

Pattern approval assesses the meter design to ensure it is:

• fit for purpose
• able to operate in the environment in which it is expected to be used.

Your meter design can be examined by:

• an approving authority 
• an appropriate test facility in Australia or overseas.

We evaluate the test results from the examination and decide whether to approve the pattern of the meter. Once approved, we issue a certificate of approval:

• gas meter certificates of approval
• electricity meter certificates of approval
• water meter certificates of approval.

Expired or cancelled certificates of approval

You can install and use a meter for trade with an expired or cancelled certificate of approval as long as:

• the certificate of approval was valid at the time the meter was manufactured and the National Measurement Institute (NMI) has not withdrawn the certificate
• the meter is verified.

Verification mark

Utility meter verifiers can apply verification marks as specified in the national instrument test procedures for utility meters.

Certificate of verification

Utility meter verifiers can issue a certificate of verification as specified in the national instrument test procedures for utility meters. Certificates include the meter’s pattern approval number (e.g. 14/3/25) and individual serial numbers (ABC123456).

The certificate of verification format is in the Appendix of the NITP 14: national instrument test procedures for utility meters.

Repairing or adjusting meters

If you make a repair or adjustment to a verified meter that affects the metrological performance or breaks the metrological seal, the meter must be re-verified before you can use it for trade. While adjusting or repairing, you must not substantially modify the meter to, in effect, create a different meter design or pattern.

Software and firmware updates

You can make software or firmware changes to pattern approved meters as long as these changes do not affect the meter’s metrological performance. The certificate owner (typically the manufacturer) must submit any changes that do affect the performance to us for approval.

Gas meters

You are not required to have gas meters pattern approved and verified under trade measurement laws.

Electricity meters

All electricity meters must be pattern approved and verified if they:

• were installed on or after 1 January 2013
• measure less than 750 MWh per year.

Pattern approval

NMI assesses electricity meters for pattern approval in accordance with one of the following standards:

• NMI M 6 for active-energy electricity meters, based on NMI M 6 (2020).
• NMI M 13 for active-energy electricity meters, based on the Standards Australia adoption of a suite of International Electrotechnical Commission (IEC) standards.
• NMI R 46 for active-energy electricity meters, based on the International Organisation for Legal Metrology Recommendation 46, OIML R 46 (2012).

See pattern approval requirements for these documents.

Sub-meters 

If you operate a building or site with multiple meters and use sub-meters for billing, these sub-meters must be pattern approved and verified. You use a meter for trade if you use the measurement to determine the amount to pay for a transaction, even proportionally.

Water meters

All cold water meters must be pattern approved and verified if they have a maximum continuous flow rate (Q3):

• equal to or less than 4,000 L/h and were installed on or after 1 July 2004
• equal to or less than 16,000 L/h and were installed on or after 1 July 2014.

Hot water meters do not need to be pattern approved and verified.

Water meters used in recycled water applications

The National Measurement Institute (the NMI) is aware that verified water meters approved under the pattern approval requirements for water meters used for cold potable water and hot water (NMI R 49) are being used in recycled water applications.

Whilst the scope of NMI R 49 does not include ‘recycled water’, the NMI will not take any compliance and enforcement action in relation to the use of such meters for trade and billing purposes, under the following conditions:

• Applicable water meters used for trade or billing must be pattern approved and verified.
• Applicable water meters/installations must comply with all relevant Australian Standards.
• Applicable water meters must operate within the relevant maximum permissible errors.

Note: Water meters used in recycled water applications are purple in colour and may have different end connections to prevent interchange with a drinking water meter.

Pattern approval 

NMI assesses water meters for pattern approval in accordance with one of the following standards:

• NMI R 49 – meters intended for potable cold and hot water
• NMI M 10 – meters intended for large scale, non-potable applications
• NMI M 11 – meters intended for open channel flow measurement.

See pattern approval requirements for these documents.

Exempt water meters

The following water meters are exempt from the pattern approval and verification requirements of the National Measurement Act 1960:

• all hot water meters
• cold water meters with a maximum continuous flow rate (Q3) of more than 16,000 L/h.

You may elect to pattern approve and verify an exempt water meter in order to:

• provide confidence in its design and performance or,
• comply with state and territory requirements for non-urban water meters.

Approved patterns and meter accuracy

NMI issues certificates of approval with respect to the design (the pattern) of a water meter. The calibration and measurement accuracy of individual water meters should be verified:

• using the test procedures specified in the certificate of approval or
• as required by relevant legislation.

Devices used to read measurement results from utility meters

You may want to install a device on or near a utility meter to read the measurement results from its indicator. This device might be a camera and its associated software.

If you do, the device is not considered a measuring instrument used for trade, provided it doesn't:

• obscure or replace the meter indicator
• influence or affect the operation of the meter.