In November 2023, ProPublica and The Desert Sun published an investigation that should change how anyone in Arizona talks about water. Reporters used NASA satellite data and county land records to estimate, field by field, who actually drinks the Colorado River. The answer: in California's Imperial Valley, a majority of the water consumed by farms goes to members of just 20 extended families. In 2022 they used roughly 1 in every 7 drops that flowed through the entire Lower Basin.

One thing to settle up front. This is not an argument that those families are the problem, that farming is the villain, or that a dry river is anyone's fault in particular. They farm legally, under rights the Supreme Court has upheld more than once, and they grow what the market and the law make rational to grow. If the roles were reversed, most of us would do the same.

The argument is about perspective. When a data center comes before an Arizona town, the first objection is almost always water, and it usually arrives as a number: so many millions of gallons a year. The number is real. What is missing is any sense of what it means, what it buys, or how it compares to anything else in the state's water picture. Those are the three questions this piece tries to answer.

First, What a Million Gallons Is

Water in the West is measured in acre-feet, a unit almost nobody outside the industry can picture. So start there. An acre-foot is a football field, end zones included, under nine inches of water. It is about 326,000 gallons. It is half an Olympic swimming pool. It is roughly what two Arizona households use in a year.

Remember the pool. One Olympic pool is almost exactly two acre-feet, and it is the yardstick for everything below.

The Numbers That Reset the Scale

The Imperial Irrigation District holds the single largest entitlement on the Colorado River, 3.1 million acre-feet a year, with 2.6 million of those carrying a 1901 priority date that Congress and the U.S. Supreme Court have repeatedly upheld. One irrigation district has a bigger and older claim to the river than the states of Nevada and Arizona.

Five members of one family inside that district, the Abattis, used an estimated 260,000 acre-feet in 2022, about 3 percent of the Colorado River's entire Lower Basin flow. Southern Nevada used less. Everything in metro Las Vegas, all two million people, every casino on the Strip, every golf course, every lawn, came to about 220,000.

Now put a data center next to that. A 100-megawatt hyperscale facility running full-load evaporative cooling in a hot climate uses up to about 1,500 acre-feet of water a year, roughly what two and a half Phoenix golf courses use. That is the high end of published figures: Google's 2025 environmental report shows its largest US data center consuming 2.8 million gallons a day, with 16 of its 24 North American sites withdrawing under 1 million gallons a day, and independent estimates put a hot-climate 100-megawatt evaporative build at 350 to 500 million gallons a year. It is also the design metro Phoenix stopped approving a decade ago; the closed-loop and air-cooled systems built there today use a fraction of it, or none at all.

Every data center number in this article is the high end of the worst case: a full-load evaporative build of a kind metro Phoenix stopped approving a decade ago. What actually gets built uses far less. The deck is stacked against the data center deliberately, because an argument that needs favorable numbers is not much of an argument.

In pools: that same data center, at the top of its worst-case range, fills about 740 Olympic pools a year. The Abatti family filled 128,000. Metro Las Vegas, all of it, filled fewer than the Abattis did. The whole Imperial Valley filled about 1.17 million, the water footprint of roughly 1,600 hundred-megawatt data centers running the thirstiest cooling made. Arizona has not built sixteen hundred of anything.

<figure class="infographic"> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 560" role="img" aria-label="Annual Colorado River water use compared: one data center against Las Vegas, one farming family, hay, Arizona's 2027 cut, and the Imperial Valley"> <text x="20" y="36" font-family="ui-monospace, SFMono-Regular, Menlo, Consolas, monospace" font-size="11" fill="#9aa0b0" letter-spacing="3">ONE YEAR OF WATER, TO SCALE</text> <text x="20" y="66" font-family="Inter, sans-serif" font-size="22" fill="#FFFFFF" font-weight="700">The data center bar is too small to draw</text> <text x="20" y="90" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">Acre-feet per year, with the Olympic-pool equivalent. Bars are on one linear scale.</text>

<text x="20" y="138" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">One 100 MW data center, worst-case evaporative cooling</text> <rect x="20" y="148" width="3" height="18" fill="#3C90CC"/> <text x="34" y="162" font-family="Inter, sans-serif" font-size="14" fill="#3C90CC" font-weight="600">1,500 acre-feet</text> <text x="152" y="162" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">740 pools. At this scale the bar is barely one pixel wide.</text>

<text x="20" y="212" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">All of metro Las Vegas, 2022</text> <rect x="20" y="222" width="89" height="18" fill="#3C90CC" opacity="0.7"/> <text x="119" y="236" font-family="Inter, sans-serif" font-size="14" fill="#FFFFFF" font-weight="600">220,000</text> <text x="188" y="236" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">108,500 pools</text>

<text x="20" y="286" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">The Abatti family, five members, 2022</text> <rect x="20" y="296" width="105" height="18" fill="#D84824" opacity="0.8"/> <text x="135" y="310" font-family="Inter, sans-serif" font-size="14" fill="#FFFFFF" font-weight="600">260,000</text> <text x="204" y="310" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">128,000 pools</text>

<text x="20" y="360" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">Hay grown by the top 20 families, per year</text> <rect x="20" y="370" width="277" height="18" fill="#D84824" opacity="0.8"/> <text x="307" y="384" font-family="Inter, sans-serif" font-size="14" fill="#FFFFFF" font-weight="600">685,000</text> <text x="376" y="384" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">338,000 pools</text>

<text x="20" y="434" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">Arizona's Colorado River cut, 2027 and 2028</text> <rect x="20" y="444" width="307" height="18" fill="#3C90CC" opacity="0.7"/> <text x="337" y="458" font-family="Inter, sans-serif" font-size="14" fill="#FFFFFF" font-weight="600">760,000</text> <text x="406" y="458" font-family="Inter, sans-serif" font-size="13" fill="#9aa0b0">375,000 pools</text>

<text x="20" y="508" font-family="Inter, sans-serif" font-size="15" fill="#FFFFFF" font-weight="600">The whole Imperial Valley, 2022</text> <rect x="20" y="518" width="958" height="18" fill="#D84824" opacity="0.8"/> <text x="30" y="532" font-family="Inter, sans-serif" font-size="14" fill="#FFFFFF" font-weight="600">2.37 million</text> <text x="128" y="532" font-family="Inter, sans-serif" font-size="13" fill="#0C0C14" font-weight="600">1.17 million pools, about 1,600 data centers' worth</text> </svg> <figcaption>One Olympic pool is about two acre-feet. Data center figure assumes evaporative cooling, the worst case; most new Phoenix builds use far less. Sources: ProPublica and The Desert Sun, Imperial Irrigation District, U.S. Department of the Interior, AZDCA.</figcaption> </figure>

What the Water Grows

The reflex defense of Imperial Valley farming is that it keeps lettuce, broccoli and onions on American tables in winter. Some of it does. But ProPublica found that most of the top families put the bulk of their water on hay. Sixteen of the top 20 families mostly grow hay, and that takes an estimated 685,000 acre-feet a year, more than four times what San Diego's entire 1.4 million-person water district uses. The crop feeds cattle, not people.

Some of that hay leaves the country. In 2022, about 2 million tons of hay were exported from Southern California ports, half of it to China, with Saudi Arabia taking roughly 200,000 tons of alfalfa because it banned growing the crop at home to protect its own groundwater. The district gets the river water for free from the Bureau of Reclamation and charges growers about $20 an acre-foot. Cheap, senior, federally delivered water grows a forage crop, and a meaningful share of that crop ships overseas to feed other nations' livestock.

None of that is cheating. Alfalfa is the rational crop for that water under those rules, hay is a real product with real buyers, and dairy and beef are part of the food supply. What it is not is a conversation-ending fact. "At least it grows food" is true. It is also something a data center can say, which is the part of this argument nobody runs.

Data Centers Grow Food Too

A growing share of what runs inside a data center is agriculture. Precision irrigation depends on it. The sensor-and-model systems that tell a farmer how much water each field needs, and when, run on cloud compute. A systematic review of 135 studies published between 2018 and 2025 found AI-driven irrigation cut on-farm water use by roughly 30 to 50 percent while raising yields 20 to 30 percent. The Yuma-area operation described in What 100 Megawatts Actually Does is a concrete version of the same thing: a model running in a data center somewhere in the Southwest, pumping decisions every fifteen minutes, an aquifer that draws down slower than it used to.

Consider what that means arithmetically. A 100-megawatt facility uses at most about 1,500 acre-feet a year, and far less if it is built the way Phoenix now requires. If the models running inside it trim even a few percent from the irrigation water of the farms that subscribe, the facility is water-positive for the region before anyone counts the radiology, the telehealth, the captioning or the payroll. Nobody has fully tallied that ledger, and this article is not claiming a precise number. The point is narrower. "It grows food" settles nothing, because both sides grow food. One of them is also the most regulated new water user in Arizona, and the one most likely to reduce somebody else's consumption.

Why They Own the River, and Why It Won't Change

The obvious question is why anyone is allowed to flood-irrigate export hay in a drought while cities ration their tap water. The answer is a body of law built to settle the arid West a century ago, and it is working exactly as written.

Western water runs on prior appropriation: first in time, first in right. Whoever put the water to beneficial use first holds the senior claim, and in a shortage senior rights are filled completely before junior users get a single drop. The Imperial Irrigation District's claim traces to diversions that began around 1901, which makes it about as senior as any user on the Lower Colorado. That seniority is frozen into what is called the Law of the River, the stack of compacts, federal acts, contracts and court decrees governing the system. Four documents carry most of the weight: the 1922 Compact, the 1928 Boulder Canyon Project Act, California's 1931 Seven Party Agreement ranking the farm districts ahead of the cities, and the Supreme Court's 1963 decree in Arizona v. California. IID's core entitlement is a "present perfected right," a vested property right that predates and outranks almost everything else on the river.

Two features make this close to impossible to reform. First, these are property rights, not permits. Government cannot simply revoke them. It has to buy them out or condemn them, and condemning water rights triggers Fifth Amendment takings fights nobody wants. So the only lever that moves water is cash. The district wants federal taxpayers to fund $840 per acre-foot conservation payments for water that earns roughly $300 an acre-foot growing alfalfa.

Second, the doctrine punishes conservation. Under "use it or lose it," a rights holder who doesn't put the full allocation to beneficial use can forfeit the unused portion to the next user in line. So the law rewards spreading as much water as possible across the thirstiest reliable crop, which is exactly what alfalfa is. The behavior that looks wasteful from the outside is the rational response to the incentives the rules create. Changing it means rewriting a system locked behind seven states, Mexico, thirty tribes and Congress, with the most senior holder, California, having the least reason to give anything up. "It is what it is," Gov. Gavin Newsom told The Desert Sun when asked if the arrangement was fair. "It's called senior water rights, and they are well established in law. And they matter."

Now the part that should bother everyone. These rights are more than 120 years old. Nobody alive voted for them. Almost nobody in Arizona knows they exist. And they sit senior to every household in Phoenix, Tucson, Las Vegas and Reno. A resident who has never heard of the Seven Party Agreement is, in a shortage, junior to a hay field in another state. That is not a scandal. It is the system. But a public that argues about water without knowing it is arguing in the dark.

Why This Matters for Arizona

Arizona sits on the wrong end of that priority stack. To get the Central Arizona Project authorized in 1968, the state agreed that CAP water would be junior to California's senior rights. The bill comes due in a shortage. When the federal government declared Colorado River shortages in 2022 and 2023, Arizona's CAP absorbed the deepest mandatory cuts in the basin while the Imperial Valley, holding senior rights, surrendered nothing it didn't choose to sell. Three years later it happened again, several times larger, and it is now federal policy through 2028.

Arizona also has a structural advantage the Imperial Valley does not. The 1980 Groundwater Management Act and the Active Management Area framework subject every large industrial user, data centers included, to rules that simply do not exist for Imperial's grandfathered farmers. A 100-megawatt campus that pays industrial tax rates, employs a four-figure operations team, runs increasingly on reclaimed water and closed-loop cooling, and has to prove a 100-year assured water supply before it can break ground is the most accountable new water user in the state. The thing critics fear about data centers, unaccountable water use, is far closer to reality on the agricultural side of the line, and far better governed on the data center side, than the public debate assumes.

The 2027 Cuts, and Where They Land

The rules that have governed Lake Powell and Lake Mead since 2007 expire at the end of 2026, and the seven basin states spent three years failing to agree on what replaces them. On August 21, 2026, Interior stopped waiting. Secretary Burgum signed the 2027-2028 Operating Guidelines and a Record of Decision that set a ten-year framework through 2036, to be filled in two years at a time. The combined contents of Powell and Mead are lower than at any point since Powell began filling in 1963, after the lowest snowpack on record in the winter of 2025-26.

The headline number is a 1.25 million acre-foot cut to Lower Basin deliveries in each of 2027 and 2028, plus at least 700,000 acre-feet of additional voluntary conservation over the two years. The three Lower Basin states proposed how to split it, and Interior wrote that split into the rules: Arizona 760,000 acre-feet, California 440,000, Nevada 50,000.

Set that against what each state was promised in 1928: California 4.4 million acre-feet, Arizona 2.8 million, Nevada 300,000. Arizona holds about 37 percent of the Lower Basin's water and is taking 61 percent of the cut. Arizona surrenders roughly a quarter of its river supply. California surrenders a tenth. That is the 1968 CAP bargain doing exactly what it was written to do, and it is deeper than any shortage cut Arizona has taken before.

For scale, Arizona's cut is about 375,000 Olympic pools a year, the water footprint of roughly 500 hundred-megawatt data centers built to the least efficient cooling standard made. Arizona has nowhere near that many and never will. The state is giving up, in one year, more river water than every data center it could plausibly build.

What the new rules do not do is touch the Imperial Valley's senior rights. The framework says shortages get shared by agreement in the Lower Basin or, absent agreement, according to the Law of the River, which means priority. The Imperial Irrigation District said so plainly: any change to how shortages are shared must come through voluntary agreements, and IID will keep helping provided its rights are protected, the terms are fair and participation stays voluntary. California's 440,000 acre-foot share is a negotiated contribution, and the district's part of it is paid conservation.

That conservation is real, and it is the fairest thing to be said about the valley. IID reports more than 9.2 million acre-feet conserved since 2003 through on-farm efficiency, system improvements and paid fallowing. Roughly 900,000 acre-feet of that came in the last four years, with up to another 100,000 in 2026, which the district credits with adding more than 13 feet of elevation to Lake Mead. That 9.2 million is more water than metro Las Vegas uses in forty years, given up voluntarily. They are not sitting on their hands. They are conserving on their own terms, for a price, under rights nobody can compel, and the law is on their side.

The Honest Frame

The river is genuinely overallocated. For a century, allocations assumed about 17.5 million acre-feet would flow each year. The real number, especially since 2000, has been far less, closer to 12.4 million. There is not enough water, and hard choices are coming for everyone who draws from the river, farms, cities and industry alike.

But honest scarcity math starts with where the water goes and what it buys. ProPublica's methodology holds up. It cross-checked satellite evapotranspiration data against the district's own crop and soil records, had independent experts review it, and landed within 0.1 percent of the district's reported total deliveries. The Imperial Irrigation District declined to release the underlying customer data and then did not dispute the findings. This is about as solid as water-use estimation gets without direct meter access.

Data centers are the target of the moment. Some of that is earned, the industry has been slow to explain itself, and some of it is a political and economic wave that needed a face. Either way, the objection deserves a real answer rather than a reflex, and the real answer starts with proportion. A million gallons is three acre-feet, a pool and a half, six households for a year. A hyperscale campus, even at its thirstiest, is several hundred pools attached to a tax base, a payroll, a regulator, and a lengthening list of things it does for the farms, hospitals and classrooms running on it. The Colorado's shortage was written into law in 1922 and 1968, long before the first server rack, by people who could not have imagined either the drought or the machines.

The twenty families are not the boogeyman. Neither are data centers. Every one of us is downstream of decisions made without us. The way to stop being surprised by them is to look at the whole picture, count in units we can feel, and show up for the decisions being made now. That is what the data center industry is asking Arizona to do with it, and it is what Arizona should be asking of the river.

Fact Check

We validated the central claims in the ProPublica/Desert Sun investigation against independent sources before publishing this. The Imperial Irrigation District's 3.1 million acre-foot entitlement and 1901 senior priority date are confirmed by IID's own filings. The Abatti family's 260,000 acre-feet versus Southern Nevada's roughly 220,000 acre-feet was independently reported by the Las Vegas Review-Journal and Las Vegas television coverage. The 2022 hay export figures (2 million tons from Southern California ports, half to China, about 200,000 tons to Saudi Arabia) and the $20 per acre-foot water rate are corroborated across multiple outlets. The Colorado River overallocation (allocations built on roughly 16.5 to 17.5 million acre-feet against actual flows closer to 12.4 million since 2000) is well documented by the Water Education Foundation and federal sources. The legal framework is also well established: prior appropriation, the present perfected rights confirmed in Arizona v. California (1963), and the "use it or lose it" forfeiture rule are basic Western water law, and Arizona's CAP supply was made junior to California's under the 1968 Colorado River Basin Project Act, which is why CAP took the basin's deepest cuts in the 2022 and 2023 shortage declarations. ProPublica issued one correction after publication, on the affiliation of a quoted researcher, not on any of the water-use findings. The investigation holds up.

The 2026 federal decision was checked against primary sources. The August 21, 2026 signing, the 1.25 million acre-foot annual Lower Basin reduction for 2027 and 2028, the 760,000 / 440,000 / 50,000 state split, the 700,000 acre-foot voluntary conservation figure, the ten-year framework through 2036, and the record-low reservoir and snowpack statements all come from Interior's own press release. The 4.4 / 2.8 / 0.3 million acre-foot apportionments are the 1928 Boulder Canyon Project Act figures confirmed in Arizona v. California. The percentage comparisons are arithmetic off those numbers. IID's position on senior rights, the 9.2 million acre-feet conserved since 2003, the roughly 900,000 acre-feet of system conservation over four years and the 13 feet of Lake Mead elevation are IID's own statements from its July 31, 2026 release and are presented as the district's claims.

The 100-megawatt water figure is the high end of the published 600 to 1,500 acre-feet per year range for a full-load evaporative build, a design metro Phoenix stopped approving roughly a decade ago; reported facility consumption in Google's 2025 environmental report supports the upper part of that range. Every comparison in this article uses the 1,500 figure, which is the least favorable number available to the data center side. Unit conversions: one acre-foot is 325,851 U.S. gallons. An Olympic pool is 2,500 cubic meters, about 660,430 gallons, so one pool is 2.03 acre-feet; pool figures in the chart and text are rounded from that ratio. A football field including end zones is 1.32 acres, so one acre-foot covers it to about nine inches. The "two households" figure uses a typical Arizona single-family use of roughly half an acre-foot per year and is an approximation. The 30 to 50 percent irrigation water savings figure is the range reported by a 2025 meta-analysis of 135 studies in Smart Agricultural Technology and applies to AI-driven irrigation systems in the studied contexts, not to all farms.

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