Handbook 44 – 2010 3.36. Water Meters 

Table of Contents 

Section 3.36. Water Meters.................................................................................................... 3-93

A. Application .................................................................................................................................................. 3-93

S. Specifications............................................................................................................................................... 3-93

S.1. Design of Indicating and Recording Elements and of Recorded Representations............................. 3-93

S.1.1. Primary Elements................................................................................................................. 3-93

S.1.2. Graduations.......................................................................................................................... 3-94

S.1.3. Indicators. ............................................................................................................................ 3-94

S.2. Design of Measuring Elements.......................................................................................................... 3-95

S.2.1. Provision for Sealing............................................................................................................ 3-95

S.2.2. Batching Meters Only.......................................................................................................... 3-95

S.2.3. Multi-Jet Meter Identification.............................................................................................. 3-95

N. Notes............................................................................................................................................................. 3-95

N.1. Test Liquid......................................................................................................................................... 3-95

N.2. Evaporation and Volume Change. ..................................................................................................... 3-95

N.3. Test Drafts. ........................................................................................................................................ 3-95

N.4. Testing Procedures............................................................................................................................. 3-95

N.4.1. Normal Tests........................................................................................................................ 3-95

N.4.2. Special Tests. ....................................................................................................................... 3-96

N.4.3. Batching Meter Tests. .......................................................................................................... 3-96

T. Tolerances.................................................................................................................................................... 3-97

T.1. Tolerance Values. .............................................................................................................................. 3-97

T.1.1. Repeatability. ....................................................................................................................... 3-97

UR. User Requirements ..................................................................................................................................... 3-97

UR.1. Batching Meters Only........................................................................................................................ 3-97

UR.1.1. Strainer................................................................................................................................. 3-97

UR.1.2. Siphon Breaker. ................................................................................................................... 3-97

UR.1.3. Provision for Testing............................................................................................................ 3-97

UR.2. Accessibility of Customer Indication................................................................................................. 3-97

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Handbook 44 – 2010 3.36. Water Meters 

Section 3.36. Water Meters 

A. Application 

A.1. This code applies to devices used for the measurement of water; generally applicable to, but not limited to, 

utilities type meters installed in residences or business establishments and meters installed in batching systems. 

(Amended 2002) 

A.2. This code does not apply to: 

(a) water meters mounted on vehicle tanks (for which see Section 3.31. Code for Vehicle-Tank Meters) or 

(b) mass flow meters (see Section 3.37. Code for Mass Flow Meters). 

(Added 1994) 

A.3. See also Section 1.10. General Code requirements. 

S. Specifications 

S.1. Design of Indicating and Recording Elements and of Recorded Representations. 

S.1.1. Primary Elements. 

S.1.1.1. General. – A water meter shall be equipped with a primary indicating element and may also be 

equipped with a primary recording element. Such elements shall be visible at the point of measurement or 

be stored in non-volatile and nonresettable memory. The display may be remotely located provided it is 

readily accessible to the customer. 

(Amended 2002) 

S.1.1.2. Units. – A water meter shall indicate and record, if the device is equipped to record, its 

deliveries in terms of liters, gallons or cubic feet or binary or decimal subdivisions thereof except batch 

plant meters, which shall indicate deliveries in terms of liters, gallons or decimal subdivisions of the liter or 

gallon only. 

S.1.1.3. Value of Smallest Unit. – The value of the smallest unit of indicated delivery and recorded 

delivery, if the device is equipped to record, shall not exceed the equivalent of: 

(a) 50 L (10 gal or 1 ft3

) on utility type meters, sizes 1 in and smaller, or 

(b) 500 L (100 gal or 10 ft3) on utility-type meters, sizes 11⁄2 in and 2 in, or 

(c) 0.2 L (1

/10 gal or 1/100 ft3) on batching meters delivering less than 375 L/min (100 gal/min or 

13 ft3

/min), or 

(d) 5 L (1 gal or 1

/10 ft3) on batching meters delivering 375 L/min (100 gal/min or 13 ft3/min) or more. 

 (Amended 2009) 

S.1.1.4. Advancement of Indicating and Recording Elements. – Primary indicating and recording 

elements shall be susceptible to advancement only by the mechanical operation of the device. 

S.1.1.5. Return to Zero. – If the meter is so designed that the primary indicating elements are readily 

returnable to a definite zero indication, means shall be provided to prevent the return of these elements 

beyond their correct zero position. 

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3.36. Water Meters Handbook 44 – 2010 

S.1.1.6. Proving indicator. – Utility-type meters shall be equipped with a proving indicator. The 

individual graduations on a mechanical (analog) proving indicator shall indicate volumes no larger than 1

/100

of the value of the smallest unit of indicated delivery required in S.1.1.3. For electronic (digital) proving 

indications, the smallest unit of volume displayed shall be no larger than 1

/1000 of the value of the smallest 

unit of indicated delivery required in S.1.1.3. 

(Added 2009) 

S.1.2. Graduations. 

S.1.2.1. Length. – Graduations shall be so varied in length that they may be conveniently read. 

S.1.2.2. Width. – In any series of graduations, the width of a graduation shall in no case be greater than 

the width of the minimum clear interval between graduations, and the width of main graduations shall be 

not more than 50 % greater than the width of subordinate graduations. Graduations shall in no case be less 

than 0.2 mm (0.008 in) in width. 

S.1.2.3. Clear Interval Between Graduations. – The clear interval shall not be less than 1.0 mm 

(0.04 in). If the graduations are not parallel, the measurement shall be made: 

(a) along the line of relative movement between the graduations at the end of the indicator, or 

(b) if the indicator is continuous, at the point of widest separation of the graduations. 

S.1.3. Indicators. 

S.1.3.1. Symmetry. – The index of an indicator shall be symmetrical with respect to the graduations, at 

least throughout that portion of its length associated with the graduations. 

S.1.3.2. Length. – The index of an indicator shall reach to the finest graduations with which it is used, 

the width of the minimum clear interval between graduations, and the width of main graduations shall be 

not more than 50 % greater than the width of subordinate graduations. Graduations shall in no case be less 

than 0.2 mm (0.008 in) in width. 

S.1.3.3. Width. – The width of the index of an indicator in relation to the series of graduations with 

which it is used shall not be greater than: 

(a) the width of the narrowest graduation*, and 

[*Nonretroactive as of January 1, 2002]

(Amended 2001) 

(b) the width of the minimum clear interval between graduations. 

When the index of an indicator extends along the entire length of a graduation, that portion of the index of 

the indicator that may be brought into coincidence with the graduation shall be of the same width 

throughout the length of the index that coincides with the graduation. 

S.1.3.4. Clearance. – The clearance between the index of an indicator and the graduations shall in no 

case be more than 1.5 mm (0.06 in). 

S.1.3.5. Parallax. – Parallax effects shall be reduced to the practicable minimum. 

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Handbook 44 – 2010 3.36. Water Meters 

S.2. Design of Measuring Elements. 

S.2.1. Provision for Sealing. – Adequate provision shall be made for applying security seals in such a 

manner that no adjustment or interchange may be made of: 

(a) any measurement elements, and 

(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 

deliveries. 

The adjusting mechanism shall be readily accessible for purposes of affixing a security seal. 

S.2.2. Batching Meters Only. 

S.2.2.1. Air Elimination. – Batching meters shall be equipped with an effective air eliminator. 

S.2.2.2. Directional Flow Valves. – Valves intended to prevent reversal of flow shall be automatic in 

operation. 

S.2.3. Multi-Jet Meter Identification. – Multi-Jet water meters shall be clearly and permanently marked as 

such on the device or identified on the Certificate of Conformance. 

(Added 2003) 

N. Notes 

N.1. Test Liquid. – A meter shall be tested with water. 

N.2. Evaporation and Volume Change. – Care shall be exercised to reduce to a minimum, evaporation losses 

and volume changes resulting from changes to temperature of the test liquid. 

N.3. Test Drafts. – Test drafts should be equal to at least the amount delivered by the device in 2 minutes and in 

no case less than the amount delivered by the device in 1 minute at the actual maximum flow rate developed by the 

installation. The test draft sizes shown in Table N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests, 

shall be followed as closely as possible. 

(Amended 2003) 

N.4. Testing Procedures. 

N.4.1. Normal Tests. – The normal test of a meter shall be made at the maximum discharge rate developed 

by the installation. Meters with maximum gallon per minute ratings higher than the values specified in 

Table N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests may be tested up to the meter rating, 

with meter indications no less than those shown. 

(Amended 1990, 2002, and 2003) 

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3.36. Water Meters Handbook 44 – 2010 

Table N.4.1. 

Flow Rate and Draft Size for Water Meters Normal Tests

Maximum Rate 

Meter Indication/Test Draft 

Meter Size 

(inches) 

Rate of Flow 

(gal/min) 

gal ft3

Less than 5/8 8 50 5 

 5/8 15 50 5 

 3⁄4 25 50 5 

1 40 100 10 

 11⁄2 80 300 40 

2 120 500 40 

3 250 500 50 

4 350 1000 100 

6 700 1000 100 

(Table Added 2003) 

N.4.1.1. Repeatability Tests. – Tests for repeatability should include a minimum of three consecutive 

test drafts of approximately the same size and be conducted under controlled conditions where variations in 

factors, such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 

results obtained. 

(Added 2002) 

N.4.2. Special Tests. – Special tests to develop the operating characteristics of meters may be made 

according to the rates and quantities shown in Table N.4.2. Flow Rate and Draft Size for Water Meters Special 

Tests. 

(Amended 2003) 

Table N.4.2. 

Flow Rate and Draft Size for Water Meters Special Tests 

Intermediate Rate Minimum Rate 

Meter Indication/Test Draft Meter Indication/Test Draft Meter Size 

(inches) Rate of Flow 

(gal/min) gal ft3

Rate of Flow 

(gal/min) gal ft3

Less than or 

equal to 5

/8 2 10 1 1⁄4 5 1 

 3⁄4 3 10 1 1⁄2 5 1 

1 4 10 1 3⁄4 5 1 

 11⁄2 8 50 5 11⁄2 10 1 

2 15 50 5 2 10 1 

3 20 50 5 4 10 1 

4 40 100 10 7 50 5 

6 60 100 10 12 50 5 

(Table Added 2003) 

N.4.3. Batching Meter Tests. – Tests on batching meters should be conducted at the maximum and 

intermediate rates only. 

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Handbook 44 – 2010 3.36. Water Meters 

T. Tolerances 

T.1. Tolerance Values. – Maintenance and acceptance tolerances shall be as shown in Table T.1. Accuracy 

Classes and Tolerances for Water Meters. 

(Amended 2003) 

Table T.1. 

Accuracy Classes and Tolerances for Water Meters 

Accuracy 

Class 

Application Acceptance 

Tolerance 

Maintenance 

Tolerance 

Tolerance for Special 

Tests Conducted at the 

Minimum Flow Rate 

Overregistration 1.5 % 1.5 % 1.5 % 

1.5 

Water, Other 

Than Multi-Jet

Water Meters Underregistration 1.5 % 1.5 % 5.0 % 

Overregistration 1.5 % 1.5 % 3.0 % 

1.5 

Water, MultiJet Water 

Meters Underregistration 1.5 % 1.5 % 3.0 % 

(Table Added 2003) 

T.1.1. Repeatability. – When multiple tests are conducted at approximately the same flow rate, the range of 

the test results shall not exceed 0.6 % for tests performed at the normal and intermediate flow rates, and 1.3 % 

for tests performed at the minimum flow rate, and each test shall be within the applicable tolerance. 

(Added 2002) 

UR. User Requirements 

UR.1. Batching Meters Only. 

UR.1.1. Strainer. – A filter or strainer shall be provided if it is determined that the water contains excessive 

amounts of foreign material. 

UR.1.2. Siphon Breaker. – An automatic siphon breaker or other effective means shall be installed in the 

discharge piping at the highest point of outlet, in no case below the top of the meter, to prevent siphoning of the 

meter and permit rapid drainage of the pipe or hose. 

UR.1.3. Provision for Testing. – Acceptable provisions for testing shall be incorporated into all meter 

systems. Such provisions shall include a two-way valve, or manifold valving, and a pipe or hose installed in the 

discharge line accessible to the proper positioning of the test measure. 

UR.2. Accessibility of Customer Indication. – An unobstructed standing space of at least 76 cm (30 in) wide, 

91 cm (36 in) deep, and 198 cm (78 in) high shall be maintained in front of an indication intended for use by the 

customer to allow for reading the indicator. The customer indication shall be readily observable to a person located 

within the standing space without necessity of a separate tool or device. 

(Added 2008) 

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