The California Water Code is the state’s central body of law for allocating water rights, protecting water quality, managing groundwater, responding to drought, and penalizing violations. It sits under a constitutional requirement that all water be put to reasonable and beneficial use, and it is administered primarily by the State Water Resources Control Board and nine Regional Water Quality Control Boards. What follows is a working map of the Code: what it regulates, who enforces it, and what it costs to get it wrong.
The Constitutional Ceiling on Every Water Right
Article X, Section 2 of the California Constitution requires that the state’s water be put to beneficial use “to the fullest extent of which they are capable” and that waste or unreasonable use be prevented.1Justia Law. California Constitution Article X – Section 2 This applies to every water right in California, riparian or appropriative, senior or junior. No one is entitled to waste water, whatever the paper says.
The doctrine is self-executing, so courts can enforce it directly without additional legislation. The Legislature has also built on it through the Water Code, giving the State Water Board authority to investigate and curtail unreasonable uses. In practice, the reasonable use rule functions as a hard ceiling above every allocation, and it is the legal footing for much of the state’s drought and curtailment response.
Water Rights: Riparian, Appropriative, and Permitted
California’s rights system blends two legal traditions that developed as the state grew, producing a structure unlike any other state’s.2California State Water Resources Control Board. Water Rights Process
Riparian Rights
Riparian rights belong to landowners whose property borders a natural watercourse. They came into California through English common law and entitle the owner to a reasonable share of the water flowing past the property. No permit or government approval is required, and the right applies only to water that would naturally flow in the stream.2California State Water Resources Control Board. Water Rights Process Riparian users share the available flow proportionally, so during shortages every user’s allocation shrinks together rather than any one user losing access outright.
Appropriative Rights
Appropriative rights trace back to Gold Rush mining claims and follow the rule of “first in time, first in right.” Earlier users hold higher priority than later ones, and the water does not have to be used on land adjacent to the stream. It can be diverted and transported so long as it serves a beneficial use.2California State Water Resources Control Board. Water Rights Process
Since 1914, a new appropriative right requires a permit from the State Water Board. The Board first issues a permit authorizing the diversion, then confirms the finished project through a license.3California State Water Resources Control Board. Water Rights Applications: Permitting and Licensing Program Applications can be rejected if the stream is already fully appropriated during some or all of the year.
The State Water Board balances three goals when it acts on rights: developing water resources in an orderly manner, preventing waste and unreasonable use, and protecting the environment.2California State Water Resources Control Board. Water Rights Process
Groundwater and the Sustainable Groundwater Management Act
Groundwater pumping in California was essentially unregulated for most of the state’s history, and decades of heavy extraction left many basins severely depleted. The Sustainable Groundwater Management Act (SGMA), enacted in 2014, created the first statewide framework for managing groundwater over the long term.4Department of Water Resources. Sustainable Groundwater Management Act (SGMA)
SGMA requires local agencies in high-priority and medium-priority basins to form Groundwater Sustainability Agencies and adopt Groundwater Sustainability Plans. Those plans must address overdraft and set measurable objectives for preventing land subsidence, saltwater intrusion, and other harms of over-pumping.5California State Water Resources Control Board. Overview of the Sustainable Groundwater Management Act Basins in critical overdraft must reach sustainability by January 31, 2040, and other covered basins by January 31, 2042.
Small users are treated more lightly but not exempted. A “de minimis extractor” pumps two acre-feet or less per year for domestic purposes. Local agencies can still require these users to report their groundwater use, and if the State Water Board places a basin on probation and finds that domestic pumping is substantially affecting the basin, even de minimis users can be required to report well locations and extraction data directly to the state.
Water Quality Under the Porter-Cologne Act
The Porter-Cologne Water Quality Control Act, codified in Division 7 of the Water Code, is the state’s foundational water quality law. It declares that all waters of the state must be protected and that activities affecting water quality must be regulated to achieve the highest quality reasonable given competing demands.6California Legislative Information. California Code Water Code 13000 Porter-Cologne works alongside the federal Clean Water Act, and in some respects is broader because it covers both surface water and groundwater.
Administration is split two ways. The State Water Board sets statewide policy and hears appeals. Nine Regional Water Quality Control Boards handle day-to-day permitting and enforcement in their geographic areas, and each adopts a basin plan setting water quality objectives for its region.7California State Water Resources Control Board. Porter-Cologne Water Quality Control Act Water Code Division 7 and Related Sections
Waste Discharge Requirements
Anyone discharging waste that could affect water quality must file a report of waste discharge with the appropriate Regional Board.8California Legislative Information. California Code Water Code 13260 The Board then issues waste discharge requirements (WDRs) that function as permits, setting limits on what can be released and under what conditions. Municipal wastewater, food processing wastewater, and industrial discharges are all typically covered.9California State Water Resources Control Board. Waste Discharge Requirements Program Reports must be submitted under penalty of perjury, and any material change in the character, location, or volume of a discharge triggers a new filing.
Conservation Planning Requirements
The Code imposes planning obligations on larger urban and agricultural water suppliers on a five-year cycle.
Urban Water Management Plans
Suppliers serving more than 3,000 customers or delivering more than 3,000 acre-feet annually must adopt an Urban Water Management Plan and update it every five years, in years ending in zero and five. Each plan must include a 20-year supply reliability assessment, demand management measures, a water shortage contingency plan, and a discussion of recycled water use.10California Department of Water Resources. Urban Water Management Plans
Agricultural Water Management Plans
Agricultural suppliers with at least 25,000 irrigated acres must submit Agricultural Water Management Plans under the Agricultural Water Management Planning Act, part of the Water Conservation Act of 2009. Plans describe efficiency measures, infrastructure improvements, and strategies for reducing the water footprint of farming, and are updated every five years. The requirement will extend to districts with as few as 10,000 irrigated acres once additional funding is available.11Delta Stewardship Council. Agricultural Water Planning
Drought Emergencies and Curtailment
Water Code Section 1058.5 lets the State Water Board adopt emergency regulations during drought without the usual rulemaking timeline. The authority is triggered in either of two situations: a critically dry year preceded by two or more consecutive below-normal or dry years, or a governor-declared drought emergency.12California Legislative Information. California Code Water Code 1058-5
Emergency regulations can require curtailment of diversions based on the priority system, mandate conservation, promote recycling, and impose reporting obligations. Each lasts up to one year but can be renewed while drought conditions persist. Violating an emergency regulation is an infraction punishable by up to $500 per day.12California Legislative Information. California Code Water Code 1058-5
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 carries much steeper penalties than the $500-per-day infraction, as the enforcement figures below show.
Penalties Under the Water Code
Enforcement is shared by the State Water Board and the nine Regional Boards. The State Board’s Office of Enforcement employs investigators and attorneys who develop cases and bring formal actions.13California State Water Resources Control Board. Office of Enforcement Typical actions include notices, cease and desist orders, and administrative civil liability proceedings.14State Water Resources Control Board. Water Rights Enforcement Dollar amounts depend on the kind of violation, and the tiers differ sharply.
Water Rights Violations
Violating a term or condition of a water right permit, license, or registration can cost up to $1,000 per day. Violating a curtailment order is treated far more seriously: the cap jumps to $10,000 per day plus $2,500 per acre-foot diverted in violation. These penalties can be imposed administratively or through the courts, with the Attorney General petitioning the superior court at the Board’s request.15California Legislative Information. California Code Water Code 1846
Water Quality Violations
Porter-Cologne has its own penalty structure. Violating a cleanup and abatement order or other Regional Board order can bring administrative penalties of up to $5,000 per day or $10 per gallon of waste discharged. Minimums also apply: at least $500 per day when there is an actual discharge combined with a cleanup order violation, and at least $100 per day for violating an order without a discharge.16California Legislative Information. California Code Water Code 13350
Discharge-related violations under waste discharge requirements are steeper. Administratively, the Board can impose up to $10,000 per day plus $10 per gallon for volumes over 1,000 gallons that are not cleaned up. In court, those caps rise to $25,000 per day and $25 per gallon. Serious or chronic violations trigger a mandatory minimum penalty of $3,000 per violation.17California Legislative Information. California Code Water Code WAT 13385
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 using the California Consumer Price Index. AB 460 made the change, which means the dollar figures above are floors that will rise over time rather than fixed caps.18California Legislative Information. Bill Text – AB-460 State Water Resources Control Board Adjusted amounts round to the nearest $1,000 for penalties between $1,000 and $10,000, and to the nearest $5,000 for penalties above $10,000.