California Water Code: Rights, Quality, and Drought Rules

The California Water Code is the state’s primary body of law for allocating water, protecting water quality, managing groundwater, and penalizing misuse. It governs surface water rights, groundwater sustainability, discharge permits, drought curtailments, and the fines that attach when any of these rules are broken. The whole structure sits under a constitutional command that water be put to reasonable and beneficial use, which means no right in California, however old or senior, authorizes waste.

The Reasonable Use Rule Above Everything

Article X, Section 2 of the California Constitution requires that the state’s water resources be put to beneficial use “to the fullest extent of which they are capable” and that waste or unreasonable use be prevented.¹ This provision limits every water right in the state, riparian or appropriative, to the amount reasonably required for beneficial use.

The doctrine is self-executing. Courts can enforce it directly, and the Legislature has layered additional authority onto it through the Water Code, giving the State Water Resources Control Board power to investigate and curtail unreasonable uses. In practice, reasonable use acts as a ceiling on every right and the legal hook for state intervention during shortages.

Water Rights: Who Can Divert and Under What Terms

California blends two legal traditions that developed as the state grew, creating a rights system unlike any other state’s.²

Riparian Rights

Riparian rights belong to landowners whose property borders a natural watercourse. They came through English common law, require no permit, and entitle the holder to a reasonable share of the water that would naturally flow past the property.² Riparian users share available flow proportionally, so during shortages everyone’s allocation shrinks rather than any single user losing access outright.

Appropriative Rights

Appropriative rights trace back to Gold Rush mining claims and now follow a “first in time, first in right” rule: earlier users hold higher priority than later ones.² Unlike riparian rights, these are not tied to land next to a waterway. Water can be diverted and moved to a distant location so long as it serves a beneficial use.

Since 1914, any new appropriative right requires a permit from the State Water Resources Control Board. The Board first evaluates the application and issues a permit for the diversion project, then confirms the final right by issuing a license once water is actually put to use.³ Applications can be rejected when the stream is already fully appropriated during part or all of the year.

In every decision, the Board balances three goals: developing water resources in an orderly manner, preventing waste and unreasonable use, and protecting the environment.²

Groundwater Under SGMA

For most of California’s history, groundwater pumping was essentially unregulated. The Sustainable Groundwater Management Act, passed in 2014, built the state’s first comprehensive framework for long-term groundwater management.⁴

SGMA requires local agencies in high- and medium-priority basins to form Groundwater Sustainability Agencies and adopt Groundwater Sustainability Plans. The plans must address overdraft and set measurable objectives to prevent land subsidence, saltwater intrusion, and other harms from over-pumping.⁵ Basins in critical overdraft must reach sustainability by January 31, 2040. Remaining covered basins have until January 31, 2042.

Small users are not fully exempt. A “de minimis extractor” pumps two acre-feet or less per year for domestic purposes. Local agencies can still require reporting as part of a sustainability plan, and if the State Water Board places a basin on probation and finds that domestic well pumping is substantially impacting the basin, even de minimis users can be required to report well locations and extraction data to the state.

Water Quality Under Porter-Cologne

Division 7 of the Water Code, the Porter-Cologne Water Quality Control Act, is California’s foundational water quality law. It declares that all waters of the state must be protected for use and enjoyment, and that activities affecting water quality must be regulated to achieve the highest quality reasonable given competing demands.⁶ The Act works alongside the federal Clean Water Act and in many respects reaches further, covering both surface water and groundwater.

Implementation runs through two tiers. The State Water Resources Control Board sets statewide policy and hears appeals. Nine Regional Water Quality Control Boards handle permitting and enforcement within their regions, each developing a basin plan that sets water quality objectives for its area.⁷

Waste Discharge Requirements

Anyone discharging waste that could affect water quality must file a report of waste discharge with the appropriate Regional Board.⁸ The Board responds with waste discharge requirements, or WDRs, which operate as permits setting specific limits on what a facility can release and under what conditions. Typical regulated discharges include municipal wastewater, food processing wastewater, and industrial effluent.⁹ Reports are submitted under penalty of perjury, and any material change in the character, location, or volume of a discharge triggers a new filing.

Non-Point Source Pollution

Runoff from farms, construction sites, and streets carries sediment, fertilizers, and other contaminants into waterways without a single discharge point. California addresses these non-point sources through best management practices, which the Regional Boards integrate into basin plans and can enforce through orders and penalties when voluntary compliance falls short.

Conservation Planning Requirements

The Code imposes structured planning on both urban and agricultural water suppliers.

Urban Water Management Plans

Every urban supplier that serves more than 3,000 customers or delivers more than 3,000 acre-feet annually must prepare an Urban Water Management Plan and update it every five years, in years ending in zero and five. Each plan includes a 20-year supply reliability assessment, demand management measures, a water shortage contingency plan, and a discussion of recycled water use.¹⁰

Agricultural Water Management Plans

Agricultural suppliers with at least 25,000 irrigated acres must submit Agricultural Water Management Plans under the Water Conservation Act of 2009. These plans detail water efficiency measures and infrastructure improvements and are updated every five years. The threshold will drop to districts with as few as 10,000 irrigated acres once additional funding is available.¹¹

Drought Curtailment Authority

Water Code Section 1058.5 lets the State Water Board adopt emergency regulations during drought without the normal rulemaking timeline. The authority applies in a critically dry year preceded by two or more consecutive below-normal or dry years, or during a governor-declared drought emergency.¹²

Emergency regulations can require curtailment of diversions based on priority, mandate conservation measures, promote recycling, and impose reporting requirements. Each regulation lasts up to one year and can be renewed while drought conditions persist. Violating an emergency regulation is an infraction punishable by up to $500 per day.¹²

Curtailment orders hit junior rights holders first. During the 2021-2022 drought, the Board issued curtailment notices across major watersheds, ordering thousands of rights holders to stop diverting. Ignoring a curtailment order is far more expensive than the $500-per-day infraction, as the penalty tiers below show.

Penalty Tiers

The State Water Board and the nine Regional Boards share enforcement authority. The usual first step is a notice to the violator. If that does not resolve the problem, formal actions follow, including cease and desist orders and administrative civil liability proceedings.¹³ Penalties vary sharply by the kind of violation.

Water Rights Violations

Violating a term or condition of a water right permit, license, or registration carries up to $1,000 per day. Violating a curtailment order is treated far more seriously: up to $10,000 per day plus $2,500 per acre-foot of water diverted in violation. These penalties can be imposed administratively by the Board or by a superior court on petition from the Attorney General at the Board’s request.¹⁴

Water Quality Violations

Porter-Cologne has its own penalty structure. Violating a cleanup and abatement order or other Regional Board order carries administrative penalties up to $5,000 per day or $10 per gallon of waste discharged, with a minimum of $500 per day when there is an actual discharge plus a cleanup order violation, and at least $100 per day for violating an order without a discharge.¹⁵

Violating waste discharge requirements or other discharge provisions can cost more. Administratively, up to $10,000 per day plus $10 per gallon for volumes over 1,000 gallons that are not cleaned up. In court, the caps rise to $25,000 per day and $25 per gallon. Serious or repeat violations trigger a mandatory minimum of $3,000 per violation.¹⁶

Inflation Adjustments Starting in 2026

Beginning January 1, 2026, all civil and administrative penalties under the Water Code’s water rights division must be adjusted annually for inflation based on the California Consumer Price Index. AB 460 established this requirement, which turns the dollar amounts above into floors that rise over time rather than fixed caps.¹⁷ Adjusted amounts are rounded to the nearest $1,000 for penalties between $1,000 and $10,000, and to the nearest $5,000 for penalties above $10,000.

1
Justia Law. California Constitution Article X – Section 2
2
California State Water Resources Control Board. Water Rights Process
3
California State Water Resources Control Board. Water Rights Applications: Permitting and Licensing Program
4
Department of Water Resources. Sustainable Groundwater Management Act (SGMA)
5
California State Water Resources Control Board. Overview of the Sustainable Groundwater Management Act
6
California Legislative Information. California Code Water Code 13000
7
California State Water Resources Control Board. Porter-Cologne Water Quality Control Act Water Code Division 7 and Related Sections
8
California Legislative Information. California Code Water Code 13260
9
California State Water Resources Control Board. Waste Discharge Requirements Program
10
California Department of Water Resources. Urban Water Management Plans
11
Delta Stewardship Council. Agricultural Water Planning
12
California Legislative Information. California Code Water Code 1058-5
13
State Water Resources Control Board. Water Rights Enforcement
14
California Legislative Information. California Code Water Code 1846
15
California Legislative Information. California Code Water Code 13350
16
California Legislative Information. California Code Water Code WAT 13385
17
California Legislative Information. Bill Text – AB-460 State Water Resources Control Board