Under California’s Sustainable Groundwater Management Act, a de minimis extractor under SGMA is anyone who pumps two acre-feet or less of groundwater per year strictly for domestic household use. That status matters because it exempts you from the metering requirements, annual extraction reports, and most of the fees that SGMA otherwise lets groundwater sustainability agencies impose on pumpers in their basins. The protections are real, but the line between exempt and regulated is thinner than most well owners realize, and crossing it is easier than you might think.
Who Qualifies as a De Minimis Extractor
Water Code Section 10721(e) sets a two-part test: a de minimis extractor is “a person who extracts, for domestic purposes, two acre-feet or less per year.”1LegiScan. California Water Code 10721 – Definitions Both halves count equally. Pump more than two acre-feet, or pump for anything other than domestic purposes, and the classification is gone.
One acre-foot equals 325,851 gallons, so the annual cap works out to roughly 651,700 gallons, or about 1,785 gallons per day.2U.S. Geological Survey. Estimated Use of Water in the United States in 2000 – Conversion Factors For context, urban Californians average roughly 77 gallons per person per day. A four-person household at that rate uses about 112,000 gallons a year, well under the cap. The buffer is comfortable for normal residential use including some landscape irrigation, but it shrinks fast if you run a large garden, fill a pool regularly, or irrigate pasture.
What “Domestic Use” Actually Means
The State Water Resources Control Board describes domestic purposes as water used for “domestic household purposes.”3State Water Resources Control Board. SGMA Extractors FAQ Drinking, cooking, bathing, laundry, and watering a home garden all fit. The water has to serve your household, not generate revenue.
This is where rural owners most often lose the status without realizing it. A small farming operation, a home nursery selling plants, a livestock operation selling eggs or meat, or a cottage food business that uses meaningful water in production all count as commercial, even if the pumping stays under two acre-feet. Volume is irrelevant once the purpose turns commercial.
Non-commercial animals sit in a gray zone. The statute does not explicitly address a few backyard chickens or a family horse. Where the animals are strictly personal and total pumping stays under the cap, most basins treat the use as domestic, but if you are in that gray area, confirm with your local groundwater sustainability agency rather than assume.
Exemption From Metering and Annual Reporting
Water Code Section 10725.8 gives groundwater sustainability agencies broad authority to require meters and demand annual extraction statements from pumpers. Subsection (e) then carves out a blanket exception: “This section does not apply to de minimis extractors.”4California Legislative Information. California Code Water Code 10725.8 That one sentence does the real work. Your GSA cannot force a measuring device on your well and cannot make you file annual pumping reports, as long as you meet the de minimis criteria.
The exemption is not absolute. The State Water Resources Control Board can require reporting from de minimis users “if a substantial portion of the groundwater use in a basin is from de minimis users and the cumulative impact of the de minimis users is significant.”3State Water Resources Control Board. SGMA Extractors FAQ In a basin where hundreds of domestic wells collectively draw a meaningful share of the water budget, the Board can override the default and impose both reporting and an annual reporting fee. This is most likely in smaller basins packed with rural residential parcels.
Fee Protections and Their Limits
Section 10730 lets agencies charge fees for everything from plan preparation to enforcement. For de minimis users, the statute adds a conditional shield: an agency “shall not impose a fee pursuant to this subdivision on a de minimis extractor unless the agency has regulated the users pursuant to this part.”5California Legislative Information. California Code Water Code 10730 If the agency has not actively subjected you to its regulations, it cannot charge you extraction-based fees.
Two caveats. Once an agency begins regulating de minimis users under SGMA, extraction-based fees become fair game. And even without that trigger, agencies can still levy parcel-based assessments through other legal authority if they can show the parcel benefits from the groundwater management program. Those usually show up as a line item on your annual property tax bill, so check your statement for anything tied to groundwater sustainability.
You Still Need to Register the Well
Exemption from reporting is not exemption from being counted. Most agencies require a one-time well registration so the basin inventory is accurate. You will need your Assessor’s Parcel Number, the physical coordinates of the wellhead (a phone’s mapping app works), and ideally the Well Completion Report the driller filed with the California Department of Water Resources when the well was built.6Justia. California Water Code 13751 – Reports If you do not have a copy, DWR maintains a searchable online database of well logs.
Most agencies accept registration through an online portal; paper forms are usually an option too. After processing, the agency typically assigns a unique well identification number tied to your parcel. Keep it. That number is your proof of compliance if a question comes up later.
Estimating Your Pumping Without a Meter
Without a meter you are guessing, and if your usage is anywhere near the cap, guessing is risky. The simplest calculation: multiply your pump’s flow rate in gallons per minute by the minutes it runs per day, then by 365. A 10-gallon-per-minute pump running two hours a day produces about 1,200 gallons daily, roughly 438,000 gallons a year, well under the limit.
If you do not know your pump’s flow rate, a well technician or electrician can measure it during a routine service call. You can also back-calculate from your electricity bill if you know the pump’s wattage and can isolate its monthly consumption. Neither method matches a real meter for precision, but either tells you whether you are safely under or uncomfortably close. For owners near the cap, installing an inexpensive inline flow meter voluntarily is the cleanest way to end the uncertainty.
What Happens If You Exceed the Cap
The consequences are financial, not criminal, and they stack. Under Water Code Section 10732, pumping more groundwater than permitted carries a civil penalty of up to $500 per acre-foot of excess extraction.7California Legislative Information. California Code Water Code 10732 Overshooting the two-acre-foot cap by one acre-foot caps the overage penalty at $500.
A separate penalty covers violations of any GSA rule, regulation, or ordinance: up to $1,000 for the initial violation, plus $100 for each additional day the violation continues if you fail to correct it within 30 days of receiving notice.7California Legislative Information. California Code Water Code 10732 A well owner who both exceeds the cap and fails to register can face both at the same time. When setting the amount, the agency or court weighs the nature of the violation, how long it lasted, the harm it caused, and the steps you took to fix it. Self-reporting an accidental overage and cutting back pumping leads to a very different outcome than ignoring repeated notices.
Your Voice in the GSA Process
Being exempt from most fees and reporting does not make you invisible, and it should not. Section 10723.2 requires every groundwater sustainability agency to consider the interests of all beneficial users of groundwater when developing its sustainability plan, and the statute specifically lists domestic well owners as a category the agency must account for.8California Legislative Information. California Code Water Code 10723.2 Disadvantaged communities on private domestic wells get additional emphasis.
This matters because sustainability plans determine whether your well keeps producing water. Residential wells are usually shallower than agricultural or municipal supply wells, so declining water tables hit them first. If a basin’s plan allows water levels to drop below your well’s depth, the plan is technically SGMA-compliant and your tap runs dry. Showing up at public meetings during plan development, and commenting on the proposed minimum thresholds for groundwater levels, is the most effective way to protect your well’s long-term viability. By the time an agency notifies property owners of a probationary hearing, the plan is already in effect.
What SGMA Does Not Cover: Water Quality
SGMA governs how much water you pump, not whether that water is safe to drink. The federal Safe Drinking Water Act does not cover private residential wells, so no federal or state agency is testing your water or holding it to a quality standard.9U.S. Environmental Protection Agency. Private Drinking Water Wells That responsibility is yours.
The EPA recommends annual testing for total coliform bacteria, nitrates, total dissolved solids, and pH.10U.S. Environmental Protection Agency. Protect Your Home’s Water Test immediately after changes in taste, color, or odor, or after flooding, new construction, or industrial activity nearby. Add nitrite and pesticide testing if you live near agriculture; test for metals and barium if you live near older mining or drilling sites. Your county health department can point you toward local labs and tell you what contaminants are common in your area’s groundwater. Declining basin levels can concentrate contaminants in what remains, so a plan that allows significant drawdown may keep the basin sustainable on paper while degrading the quality of what comes out of your shallow domestic well.