1. Accuracy Requirements

 Meter Device Accuracy: Minimum ±5% of reading across typical operating ranges, consistent with industry expectations.

 Non resettable register: Non-resettable, tamper-proof (factory sealed), recording totalizer (cumulative volume) values of extracted water in units of gallons, cubic feet, or acre-feet.

 Technology Standards:

• Magnetic (electromagnetic) and ultrasonic meters: capable of continuous, highly accurate readouts.
• Coriolis meters: acceptable where mass flow sensitivity and density compensation are needed.
• Avoid mechanical displacement or orifice meters for high-precision billing or compliance unless technology limitations apply.

 Must be designed for inline (permanent) installation.

2. Calibration & Re Verification

 Initial Factory Calibration: All meters must come factory-certified with traceable calibration documentation (e.g. ISO 4064, AWWA standards).

 Field Verification Frequency: Reverification every three years via gravimetric, piston-prover, or master-meter comparison bench methods, in line with common utility practices. Fox Canyon Groundwater Management Agency (FCGMA) maintains a list of contractors approved to calibrate meters within its service area: https://fcgma.org/wp-content/uploads/2022/06/Approved_Flowmeter_Calibration_Contractors_190910.pdf

 Post-Repair or Tampering: Any significant maintenance or suspected tampering triggers immediate recalibration or verification prior to return to service.

 Documentation & Records: Maintain a calibration log per meter including calibration date, method, trace reference, and results of pass/fail checks.

3. Installation Standards*

 Straight Pipe Requirements: Minimum 10× pipe diameter upstream straight run and 5× downstream where feasible to assure flow profile accuracy.

 Tamper-Resistant Design: Meters installed in secure vaults or locked enclosures; seals on register or output ports.

 Air/Gas Exclusion: Use air/vapor eliminators or separators upstream of meters, particularly displacement types, to prevent gas-induced reading errors.

 Environmental Protection:

• Enclosures rated to IP65 or better in outdoor or damp environments.
• Temperature sensors (if part of volume compensation) with accuracy to ±0.5 °C and resolution of 0.2 °C, and pressure sensors to ±0.5 bar with 0.1 bar resolution, near meter inlet.

*these are provided only as guidance and you should consult with a local approved professional contractor on current requirements.

4. Meter Requirements

The minimum requirements for choosing a flow meter should ensure accuracy, durability, compliance, and data compatibility. Below is a breakdown of minimum meter selection criteria:

 Accuracy

• ± 2% or better for the device itself.
• ± 5% or better for the full installed system (as per Fox Canyon GSA).

 Flow Range Compatibility

• Meter must operate within the expected minimum and maximum flow rates for the well or pipeline with no degradation in accuracy.
• Consider turn-down ratio (ratio of maximum to minimum measurable flow) suitable for varying pumping demands.

 Telemetry / SCADA Compatibility (if applicable)

• Digital output: Modbus RTU, pulse, or analog 4–20 mA signal.
• SCADA or AMI telemetry systems: Must support connection to systems used by agencies like the Fox Canyon GSA.
• Remote Telemetry Unit (RTU) compatibility or integration is preferred.

 Environmental Durability

• Must meet IP65 or higher environmental protection rating (dust-tight and water-resistant) for outdoor/agricultural environments.
• Operating temperature range must suit local climate (e.g., –20 °C to +60 °C).
• Housing and sensor materials must be corrosion-resistant, especially if exposed to groundwater, chemicals, or brackish water.

 Non-Resettable Totalizer

• Required for regulatory compliance.
• Mechanical or digital totalizer must record cumulative volume, be tamper-resistant, and not allow reset by the user. Preferred unit of measurement is Acre Feet.

 Approved Manufacturer or Model List (if applicable)

• Must appear on local GSA/GSP meter approval lists, such as:

 Fox Canyon GSA approved meters

 California Department of Water Resources or California State Water Resources Control Board recognized meter databases

 USDA NRCS or municipal procurement listings

 Compliance with Standards (Must comply with at least one of the following):

• ISO 4064 (Measurement of Water Flow in Closed Conduits)
• AWWA C700 series (e.g., C701 for turbine, C702 for compound meters)
• NSF/ANSI 61 for drinking water applications