Rule 13 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Rule 13(2) deals with measuring instruments, the meters and gauges that are not weighing machines. It sends them to the Eighth Schedule, and rule 13(3) fixes their maximum permissible error by the same Schedule. The Eighth Schedule is the longest Schedule in the General Rules: a short set of general requirements followed by nine Parts, one for each class of instrument. If you need a product checked against the notified Schedule, start with a legal consultation.
Every measuring instrument used or intended to be used in any transaction or for protection must conform, as regards physical characteristics, configuration, constructional details, materials, performance and tolerances, to the corresponding specification in the Eighth Schedule (rule 13(2)). The maximum permissible error is the one laid down in that specification (rule 13(3)). The Schedule opens with general requirements that apply to every instrument and then has nine Parts, from volumetric container filling machines to CNG measuring systems for vehicles. Most error tables are Part-specific, so read the Part for your instrument in the official text.
What rule 13(2) and (3) say
Rule 13(2): "Every measuring instrument used or intended to be used (a) in any transaction, or (b) for protection, shall conform, as regards physical characteristics, configuration, constructional details, materials, performance, tolerances and such other details, to the corresponding specifications laid down for such measuring instrument in Eight Schedule." (The rule text spells it "Eight".)
Rule 13(3): "The maximum permissible error on such weighing or measuring instrument shall be such as is specified in the corresponding specifications laid down for such weighing or measuring instrument in Seventh Schedule or as the case may be in Eighth Schedule."
The structure mirrors rules 11 and 12. There is a use-based duty, a pointer to a Schedule, and a pointer to the error limits in that Schedule. The Schedule is the standard, and verification is a separate step. For weighing instruments see our article on the Seventh Schedule.
General requirements at the top of the Schedule
Before Part I, the Eighth Schedule ("Specifications for measuring instruments", marked "See Rule 13") sets general requirements for every measuring instrument. In summary, an instrument must:
- be of such material, design and construction that, in normal working conditions, accuracy is maintained, the operating parts keep functioning and the adjustment stays reasonably permanent;
- not be stamped unless it is complete with all parts and attachments concerned with measurement and delivery;
- keep its accuracy where it has interchangeable or reversible parts;
- if of fixed type, be installed so that the viewer gets a clear, unobstructed view of the indication of measurement and delivery; and
- be designed and built to prevent, as far as possible, tampering with its accuracy, whether inadvertent or deliberate.
The nine Parts of the Eighth Schedule
| Part | Instrument | What the Part contains (in summary) |
|---|---|---|
| I | Volumetric container filling machines | Description (a basin filled to level, then emptied into the container), general requirements such as drainage and sight glasses, a test procedure with a check measure, maximum permissible error by capacity, and sealing plugs |
| II | Bulk meters | Meters used in petroleum trade; definitions (pressure drop, slippage, flow range); positive displacement type; construction and testing |
| III | Water meters (domestic type) | Terminology (Qmax, Qn, Qmin, transitional flow rate), nominal sizes, Class A and Class B, materials, body, registration box, strainers |
| IV | Measuring systems for liquids other than water | Two sub-parts: terminology of the meter and its devices, then the metrological and technical requirements; covers fuel dispensers, with electronic equipment provisions |
| V | Volumetric container type liquid measuring device | A bucket with float and graduated dip stick, generally used for milk at purchasing centres |
| VI | Clinical thermometer | Sub-parts A (solid stem mercury-in-glass), B (enclosed scale type) and C (clinical electrical thermometers with maximum device) |
| VII | Manometers of instruments for measuring arterial blood pressure (sphygmomanometers) | VII-A non-invasive mechanical; VII-B non-invasive automated |
| VIII | Taximeters | Definitions, markings, sealing, maximum permissible errors, test conditions and test methods |
| IX | Compressed gaseous fuel (CNG) measuring systems for vehicles | Terminology, general requirements for the measuring system, model approval, and an annexure on error testing |
Two points of structure are worth knowing. Parts IV and IX are built from the same kind of material: a terminology section (including ancillary devices such as the zero-setting, printing, memory, pre-setting and price-indicating devices) and then the requirements. Part IX's requirements run under "Heading A" and "Heading B" labels. Several Parts also require a suitable plug, plate or device to take the stamp or seal of the verifying authority.
Selected points from the Parts
These are descriptions, not substitutes for the official tables.
- Part II, bulk meters. The Part states that bulk meters shall not have a capacity below 100 litres.
- Part III, water meters. The Part applies to meters for potable cold water with threaded end connections and nominal sizes up to and including 50 mm. The listed nominal sizes are 15, 20, 25, 40 and 50 mm. Meters are classified as Class A and Class B on the basis of verification scale interval and metrological characteristics.
- Part V, milk measuring device. The stated nominal capacities are 5, 10, 20 and 50 dm3, and the bucket must be marked with the nominal capacity, the maker's name or trade mark and the words "for edible liquids".
- Part VIII, taximeters. The Part limits the dispersion of indications. During a drive by distance it is 2 per cent of the true value for the initial distance and for later distances, though for initial distances below 1,000 metres it may be up to 20 metres. During a drive by time it is 3 per cent of the true value, though for initial times below 10 minutes it may be up to 20 seconds. Test methods listed are the road test, the fifth wheel test and the simulated road test.
- Part IX, CNG. The annexure's error test fills a cylinder with approximately 10 kg of gas, weighed on an instrument with a verification scale interval of 10 g or less, and compares the weight actually filled with the quantity the measuring system indicates.
For tolerance tables in Parts I, III, IV, VI and VII, and for every other numeric limit, read the Part in the official text. The scanned tables are not reliable enough for us to reproduce them.
What this means in practice
- Identify the Part. A trader with a water meter looks at Part III; a taxi operator at Part VIII; a filling station at Part IV or Part IX depending on the fuel; a clinic at Parts VI and VII. The match is by the kind of instrument named in the Schedule.
- Read the notified Schedule. Read the Eighth Schedule as notified in the Gazette (G.S.R. 11(E), 7 February 2011) or a reliable official copy, and check later amendments, before you rely on any figure.
- Do not confuse with other instruments. Weighing instruments are in the Seventh Schedule, and measures that are not instruments (cans, tapes, scales) are in the Sixth Schedule (rule 12).
- Remember separate approvals and checks. Section 22 of the Act requires approval of model before manufacture or import of a weight or measure, in the manner and on the fee prescribed; see section 22. Verification and stamping before use is required by section 24, and re-verification periods are in rule 27.
- Other laws may also apply. The Schedule includes medical and vehicle-related instruments. Other regulations may apply to such devices, but those rules are outside the sources used here.
Consequences of non-conformity
An instrument that does not meet the standards established under the Act is non-standard. The Act penalises use in section 25 and manufacture or sale in section 27, and officers may inspect, search and seize under section 15. Sections 25 and 27 were amended by the Jan Vishwas (Amendment of Provisions) Act, 2023 (in force). The Jan Vishwas (Amendment of Provisions) Act, 2026 is enacted but in force only from the date the Central Government notifies; check the notification and the articles on those sections for the amounts.
Examples
Example 1: a water meter supplier. A supplier sells domestic water meters of 20 mm nominal size to housing societies. Part III is the relevant heading, and it covers the class (A or B), materials, registration box and strainer. Before sale, the supplier should confirm that the model meets the notified Part III and is approved where required, and that units are verified before use in billing.
Example 2: a fuel dispenser operator. An operator of a CNG station uses a measuring system for vehicles. Part IX is the heading. The operator should ask the supplier for conformity and verification papers and keep them for inspection.
Common mistakes
- Relying on a blog, including this one, for Eighth Schedule tolerances. Use the notified text.
- Using a Seventh Schedule heading for a meter. Weighing instruments and measuring instruments are in different Schedules.
- Treating conformity and verification as one thing.
Need help with measuring instruments?
If you make, import or operate any of the instruments listed in the Eighth Schedule and want to match them with the notified text, or have a notice after an inspection, we can go through the papers with you in a legal consultation.
Key takeaways
- Rule 13(2) binds measuring instruments used in any transaction or for protection; rule 13(3) sends the error limits to the Schedule.
- The Eighth Schedule has general requirements and nine Parts, from filling machines to CNG measuring systems.
- Each Part has its own definitions, construction, marking, sealing and test provisions; some have error tables.
- Approval of model, verification and periodic re-verification are separate steps.
- Non-conforming instruments risk penalty, seizure and forfeiture under the Act.
Read next
- Verification Procedure for Instruments
- Legal Metrology Officers -- Powers of Inspection
- Rule 13 of the Legal Metrology (General) Rules, 2011: Weighing instruments and the Seventh Schedule
- Rule 14 of the Legal Metrology (General) Rules, 2011: Calibration of vehicle tanks and the Ninth Schedule
Disclaimer: Based on the Legal Metrology (General) Rules, 2011 (G.S.R. 11(E), 7 February 2011) as notified in 2011, read with the Legal Metrology Act, 2009 (Act 1 of 2010), the Jan Vishwas (Amendment of Provisions) Act, 2023 (in force) and the Jan Vishwas (Amendment of Provisions) Act, 2026 (in force only from the date the Central Government notifies), as on 30 September 2026. The Schedule text is the 2011 notification; later amendments, State Legal Metrology rules and notifications change; verify the current position before acting.