republic-os/legislation/us/states/ca/20172018/ab-321.md

---
type: "Bill"
title: "Groundwater sustainability agencies."
description: "Existing law, the Sustainable Groundwater Management Act, requires all groundwater basins designated as high- or medium-priority basins by the Department of Water Resources that are designated as basins subject to critical conditions of overdraft to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2020, and requires all other groundwater basins designated as high- or medium-priority basins to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2022, except as specified. The act authorizes any local agency or combination of local agencies overlying a groundwater basin to decide to become a groundwater sustainability agency for that basin, as prescribed. The act requires a groundwater sustainability agency to consider the interests of all beneficial uses and users of groundwater, as well as those responsible for implementing groundwater sustainability plans, including, among other interests, holders of overlying groundwater rights, including agricultural users and domestic well owners."
jurisdiction: "us/states/ca"
legislature: "California Legislature"
session: "20172018"
identifier: "AB 321"
citation: "California AB 321 (20172018)"
classification: ["bill"]
subjects: ["Groundwater sustainability agencies."]
status: "enacted"
primary_sponsors: ["Mathis"]
version_count: 5
action_count: 22
vote_count: 1
first_action: "2017-02-07"
last_action: "2017-07-18"
source: "openstates"
source_identifier: "ocd-bill/e4d98652-481b-4467-8036-a72e9dce075a"
source_url: "http://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180AB321"
source_hash: "c330a70ab3cc59b702cadeda49ebac2c3fad4615b65b50cf6e5d90fcd42eac8b"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-ca"]
---

# California AB 321 (20172018) — Groundwater sustainability agencies.

Existing law, the Sustainable Groundwater Management Act, requires all groundwater basins designated as high- or medium-priority basins by the Department of Water Resources that are designated as basins subject to critical conditions of overdraft to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2020, and requires all other groundwater basins designated as high- or medium-priority basins to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2022, except as specified. The act authorizes any local agency or combination of local agencies overlying a groundwater basin to decide to become a groundwater sustainability agency for that basin, as prescribed. The act requires a groundwater sustainability agency to consider the interests of all beneficial uses and users of groundwater, as well as those responsible for implementing groundwater sustainability plans, including, among other interests, holders of overlying groundwater rights, including agricultural users and domestic well owners.

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **02/07/17 - Introduced** (filed) — [source](https://leginfo.legislature.ca.gov/faces/billPdf.xhtml?bill_id=201720180AB321&version=20170AB32199INT)
2. **04/27/17 - Amended Assembly** (committee substitute) — [source](https://leginfo.legislature.ca.gov/faces/billPdf.xhtml?bill_id=201720180AB321&version=20170AB32198AMD)
3. **07/17/17 - Chaptered** (committee substitute) — [source](https://leginfo.legislature.ca.gov/faces/billPdf.xhtml?bill_id=201720180AB321&version=20170AB32196CHP)
4. **AB321** (committee substitute) — [source](http://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180AB321)
5. **06/28/17 - Enrolled** (enrolled) — [source](https://leginfo.legislature.ca.gov/faces/billPdf.xhtml?bill_id=201720180AB321&version=20170AB32197ENR)

## Votes

- Special Consent Calendar # AB321 — **39–0** (pass) · upper

## Sponsors

- Mathis — primary (person)
- Berryhill — coauthor (person)
- Cristina Garcia — coauthor (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2017-02-07** Read first time. To print. `reading-1`
- **2017-02-08** From printer. May be heard in committee March 10.
- **2017-02-21** Referred to Com. on W.,P., & W. `referral-committee`
- **2017-03-20** In committee: Set, first hearing. Hearing canceled at the request of author.
- **2017-04-04** Coauthors revised.
- **2017-04-26** From committee: Amend, and do pass as amended and re-refer to Com. on APPR. (Ayes 14. Noes 0.) (April 25). `amendment-passage, committee-passage, amendment-introduction`
- **2017-04-27** Read second time and amended. `reading-1, amendment-passage, reading-2`
- **2017-05-01** Re-referred to Com. on APPR. `referral-committee`
- **2017-05-01** Withdrawn from committee.
- **2017-05-01** Ordered to second reading.
- **2017-05-02** Read second time. Ordered to third reading. `reading-2, reading-1`
- **2017-05-04** Read third time. Passed. Ordered to the Senate. (Ayes 75. Noes 1. Page 1385.) `reading-3, passage, reading-1`
- **2017-05-04** In Senate. Read first time. To Com. on RLS. for assignment. `reading-1`
- **2017-05-18** Referred to Com. on N.R. & W. `referral-committee`
- **2017-06-13** From committee: Do pass. (Ayes 9. Noes 0.) (June 13). `committee-passage-favorable, committee-passage`
- **2017-06-14** Read second time. Ordered to third reading. `reading-2, reading-1`
- **2017-06-20** Ordered to special consent calendar.
- **2017-06-26** Read third time. Passed. Ordered to the Assembly. (Ayes 39. Noes 0. Page 1712.). `reading-3, passage, reading-1`
- **2017-06-27** In Assembly. Ordered to Engrossing and Enrolling. `committee-passage`
- **2017-07-03** Enrolled and presented to the Governor at 11 a.m.
- **2017-07-18** Approved by the Governor. `executive-signature`
- **2017-07-18** Chaptered by Secretary of State - Chapter 67, Statutes of 2017.

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/e4d98652-481b-4467-8036-a72e9dce075a`. Confidence: reported (aggregated from official California legislature records).