Surface Water Measurement

Contact Info

Contact Information – Water Measurement & Reporting
Please contact the Division of Water Rights if you have any comments or questions regarding water measurement requirements.
Division of Water Rights
Phone (916) 341-5300
Email Water Reporting:

All water right diverters authorized to divert more than 10 AF per year from rivers, creeks, springs or subterranean streams must comply with measurement regulations prepared by the Division pursuant to SB 88.  There are three ways to achieve measurement compliance: (1) Install/use a measuring device, (2) propose an Alternative Compliance Plan, or (3) utilize a measurement method for multiple diverters.  The installation and accuracy of the measurement device must be documented by a Qualified Individual.  The attached table contains measurement frequency requirements and installation deadlines.

The Division relies on annual water diversion reports for water resource planning, particularly in times of drought.  All diverters are required to submit online annual water right reports (electronic reports) of diversions through the eWRIMS Report Management System.  Online annual reports are mandatory filings that document diversions made during the previous calendar year.  The reports include data-logger submittals and certification documents.  Annual reports are still required in times of drought or if water is not used in a particular year.  Failure to achieve measurement and reporting compliance is a violation subject to civil liability so it is important you contact the Division if you need assistance.

Water Measurement Devices

Complying with Measurement Requirements

Water Measurement-Fact Sheet

Selecting a Measuring Device

Below are examples of typical measuring devices.  A diverter can use any method to measure their diversions, provided it meets the accuracy and frequency requirements for their diversion size.  In some cases, you may propose an Alternative Compliance Plan or file a Request for Additional Time for installation.

Installing the Measuring Device

The measurement device must be installed and accuracy certified by a qualified individual if your water right is authorized for 100 AF or more per year.  Any diverter, tenant or employee thereof can become a “qualified individual” for installing/certifying a water right device by completing a training course on measurement devices offered by the University of California Cooperative Extension.   A list of upcoming training classesand registration information are available on the University of California Cooperative Extension websiteClick here to see a list of qualified individuals.

Measurement Methods

In lieu of a measuring device, a diverter may propose a measurement method to comply with measurement and accuracy requirements under the regulation. Measurement Methods must be submitted on the Water Board's Water Right Form and Survey Submittal Portal.

A measurement method is a method capable of accounting for the rate of diversion where the method is likely to achieve accuracy standards comparable to those of individual measuring devices. The regulation is flexible in the types of measurement methods water users may submit as long as the measurement method meets the regulation’s accuracy standards for measurement. Water diverters are encouraged to establish collaborative measurement on a local or regional basis.

Examples of measurement methods include:

  • Multiple water right holders on a single surface supply can propose a collaborative measurement approach.
  • A single water right holder with multiple points of diversion can propose a measurement method that may preclude the need to install a measurement device at each point of diversion.

Measurement Frequency Requirements

Alternative Compliance Plans

A water right holder may request an alternative compliance approach when strict compliance is not feasible, would be unreasonable expensive, would unreasonable affect public trust resources, or would result in the waste or unreasonable use of water.  Alternative compliance plans shall describe how the diverter will attain reasonable compliance with the measurement requirements of the regulation and be accompanied by detailed documentation (see §935 of the California Code of Regulations) establishing and supporting the specific basis for requesting the alternative.

Alternative compliance plans may be considered for a variety of issues, including measurement and monitoring of small hydropower projects, points of diversion that are inaccessible for portions of the year due to snow, points of diversion with highly variable flow rates, points of diversion under tidal influence, and locations with concerns for vandalism or theft.  Click here to see a list of example alternative measurement devices.

Plans are posted on the Alternative Compliance Plan webpage with the opportunity for public comment, and are subject to review, audit or rejection by the Deputy Director of the Division.

Alternative compliance plans must be submitted online using the Division’s Water Right Form and Survey Submittal Portal and remain in effect for no more than five years with the option of renewal by resubmitting before the plan expires.

Request for Extension of Time

A diverter may submit a Request for Additional Time to comply with the measurement and monitoring requirements, contingent upon the diverter's ability to demonstrate one of the following:

  1. Financial considerations shall be considered only in cases where the diverter has requested agency funding and is awaiting grant or loan award.
  2. Extensions based on other considerations are limited to:
    1. minimum time needed to access site due to weather conditions; or
    2. minimum time needed to obtain other agency permits; or
    3. minimum time needed to comply with construction time periods set in other agency permits; or
    4. unforeseen circumstances.

Requests for Additional Time must be submitted online using the Division’s Water Right Form and Survey Submittal Portal.

Device Registration & Certification

How to register your measuring device

Following installation, all water right owners must register their devices online by logging into the Report Management System (RMS) website and selecting the link “Provide measurement device information/certification” and entering basic information such as type of device, manufacturer, and installation date.
(See example of the registration form - see page 18)

How to register a shared device used by multiple owners

Once a device is registered, multiple water rights owners that share that measuring device must claim that device by logging into the Report Management System and selecting the link “Import a measurement device from a previously submitted report”.  You will need to obtain the existing measurement ID number associated with the device (already registered) in order to link multiple water rights to the device.

How to certify accuracy of device

Each device is required to meet specified accuracy requirements in order to achieve certification. Click here for a table of accuracy requirements. The regulation calls for an initial certification report submitted along with the first annual water use report filed after the device has been installed. Percent accuracy applies to devices that record volumetric flow rates directly, or to calculations of total volume using indirect measurements of elevation, pressure, velocity, etc. and conversion factors.

Certification of device accuracy must be performed by a qualified individual. A report of certification must be submitted online using the Report Management System. Once logged into the RMS, select the link "Provide measurement device information/certification". (See example of the Certification Form - see page 19). Measuring devices should be checked for accuracy every five years and re-calibrated if necessary. Devices must be re-certified every five years whether or not they need re-calibration.

Equipment Resources

Measurement Frequency Requirements Table

Field-test Certifications Installation Deadline Required Accuracy Required Monitoring Frequency1 Qualifications for Installation and Certification
Direct Diversion
≥ 1,000 AF/yr or
Storage ≥ 1000 AF
January 1, 2017 ± 10%
(15% if installed before 1/1/2016)
Hourly Who is a “Qualified Individual”?
Direct Diversion
≥ 100 AF/yr or
Storage ≥ 200 AF
July 1, 2017 ± 10%
(15% if installed before 1/1/2016)
Storage ≥ 100 AF July 1, 2017 ± 10% Weekly
Direct Diversion
> 10 AF/yr or
Storage ≥ 50 AF
January 1, 2018 ± 15% Weekly
Storage > 10 AF January 1, 2018 ± 15% Monthly
Laboratory Certifications
(All Laboratory Certified Devices)
Installed after January 1, 2016 ± 5% As noted above

 All diversions less than < 10 AF

No measurement required No measurement required No measurement required (exceptions are listed below)

1-Exceptions to this table are listed below.  This guide does not replace existing permit or license terms that establish additional monitoring requirements.
Northern California Coastal Streams – Hourly monitoring is required for all new permits in the AB 2121 area as designated in Section 10 of the “Policy for Maintaining Instream Flow in Northern California Coastal Stream”.
Cannabis Registrations – Daily monitoring is required for all cannabis diverters as designated in Attachment A of the Cannabis Cultivation Policy.
Water Master Service & Adjudicated areas –  To learn about reporting requirements in these areas, visit the Online Reporting webpage.

Qualified Individuals Table

Category Who is a Qualified Individual?
Water rights
> 100 AF
  1. California-registered Professional Engineer, or
  2. A person under the supervision of a California-registered Professional Engineer and employed to install, operate, and maintain water measurement and reporting devices or methods; or
  3. A California-licensed contractor for C- 57 well drilling, or
  4. A California-licensed contractor for C-61 Limited Specialty/D-21 Machinery and Pumps, or
  5. Any water right owner, diverter, tenant or employee thereof can become qualified by completing a training course on measurement devices offered by the University of California Cooperative Extension.  
Water rights
< 100 AF

Person trained and experienced in water measurement and reporting.  This may include the diverter or the diverter’s agent.  A training class is not necessarily required, but is optional.

Federal agency
water rights

Hydrologist or professional engineer experienced and trained in water measurement who is employed by the federal agency in that capacity.

Regulatory Background

Core Regulatory Development

On January 19, 2016, the State Water Board adopted a Resolution to adopt an Emergency Regulation for Measuring and Reporting Water Diversions. On March 10, 2016, the regulation was submitted to the Office of Administrative Law (OAL) for review. The OAL approved this regulatory action on March 21, 2016.


    Senate Bill 88 was signed by Governor Edmund G. Brown Jr. on June 24, 2015. Sections 15 through 18 of SB 88 add measurement and reporting requirements for a substantial number of diverters.

    The legislation authorizes the State Water Board to adopt a regulation requiring measurement for water right holders and claimants who divert 10 acre-feet of water or more per year. The measurement requirement applies to approximately 12,000 water right holders and claimants. The legislation also authorizes the State Water Board to adopt a regulation requiring annual reporting from statement holders and persons authorized to appropriate under a permit, license, registration (small domestic, small irrigation, or livestock stockpond), or certificate for livestock stockpond use.

    The legislation authorizes the State Water Board to adopt an initial regulation as an emergency regulation that shall remain in effect until revised by the State Water Board. The adoption of the initial regulation is exempt from the California Environmental Quality Act (CEQA).

    The State Water Board anticipated that the new measurement requirements could present challenges to the regulated community. The State Water Board held meetings and workshops in affected areas around the state to receive input on key issues to be addressed in the emergency regulation. See the Meetings and Workshops section below for more information. The State Water Board will use the input from the meetings and workshops to shape a draft regulation which will be broadly circulated around the State in early December. The draft regulation was presented for discussion at a State Water Board Workshop on December 17, 2015.

    On January 19, 2016, the State Water Board approved a Resolution to adopt an Emergency Regulation for Measuring and Reporting Water Diversions. On March 10, 2016, the State Water Board submitted the proposed regulation to the Office of Administrative Law (OAL) for review. The OAL approved this regulatory action on March 21, 2016.

    Drought Issues

    California's recent extended drought has highlighted the need for more current and accurate information on how much water is being diverted in the various watersheds throughout the State. Even during years with more normal precipitation, rainfall and snow accumulation patterns vary widely across the State. Even though water supply may be adequate in one region, a critical water shortage can occur in another region.

    More accurate data on water diversions is needed on a timely basis for all users of water in the State to evaluate how far their water supplies can be expected to stretch. As a user of water in the State, this diversion information together with an understanding of the priority of right to use a limited water supply, will allow for better water use planning decisions. This information is critical to ensure that priority water needs are met, that water rights holders have access to the information indicating whether sufficient water is likely to be available for their beneficial uses, and to ensure that adequate flows remain instream for more senior downstream beneficial uses.

    During the 2015 drought, the State Water Board called upon the water use community to provide predictions of expected surface water diversion, and to report back on the amounts that were actually diverted. This more current information shows that the historic reporting standard does not provide accurate or timely water demand data sufficient for drought response. The new law and proposed implementing regulation is expected to address this problem.

    Benefits of Measurement and Reporting

    The State Water Board is the agency with primary responsibility for the administration and regulation of water rights in California. The State Water Board allocates surface water through a system of permits, licenses, and registrations that grant and condition the right to directly divert water and/or to divert water to storage for reasonable beneficial use. In addition, the State Water Board maintains records of water use under riparian and pre-1914 claims of right.

    The implementation of improved measurement and reporting of water rights as required under Senate Bill 88 and a proposed emergency regulation to implement the new law will improve water right administration and transparency of diversion records. More accurate and current diversion records together with their transparency allow the State Water Board and all water users to more effectively:

    • Understand and plan ahead for limited water supplies;
    • Identify water losses in a diversion system and take corrective actions to conserve water and stretch limited water supplies;
    • Assure compliance with the quantity and season limitations of existing water rights;
    • Protect the senior rights of diverters in accordance with their relative priorities;
    • Provide for efficient management and use of water during times of shortage; and
    • Improve water planning and near-term forecasting of water demand.
  • Final Measurement Regulation
  • Office of Administrative Law Review of Measurement Regulations
  • Approved Resolution 2016-0005 to Adopt Emergency Regulation (includes the adopted regulation)
  • Fact Sheet for the Emergency Regulation
  • Text of Senate Bill 88