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Every single buyer who looks at land south of Tucson asks me about water before they ask about anything else. Before price, before access, before power. Which is fine, it's the desert, you should ask. The problem is most of what people think they know about water down here is a headline they read about Phoenix or Pinal County, and it doesn't apply to the Tucson basin. So I'm going to walk through how it actually works, and every claim in here has a link so you can go check me.
The short answer
No. Tucson gets its water from three places - Colorado River water through the CAP canal, reclaimed water, and groundwater - and for years the city has been buying its full river allocation and banking what it doesn't use underground out in Avra Valley and south Tucson. When the river shortage hit, Tucson's water director went on NPR and said it basically wasn't going to affect the Tucson basin because of that bank.
Now, the 2026 story is real and it's about the river, not the aquifer. The seven basin states still can't agree on how to run the Colorado after this year, and Arizona has put a 27% cut to its own allocation on the table. That's a big deal for the city's long term planning. It matters way less if you're buying acreage on a well south of town, and the rest of this is about why.
Two totally different questions
"Is there water" is actually two questions and people mash them together all the time.
If you're buying acreage to put a house on, you're in the world of private wells, and that's a filing, not an approval. If you're buying land to cut up into a bunch of small pieces, you're in the world of the 100-year assured water supply, which is a state program with actual published rules. Different worlds. Don't mix them up, because the headlines are almost always about the second one and the buyers calling me are almost always in the first one.
Wells - what the law actually says
A domestic well pumping up to 35 gallons a minute is exempt under state law. 35 is the max, not something you have to hit. You file a Notice of Intention to Drill with ADWR, you use a licensed driller, you register the well when it's done. No certificate. No hydrology study. That's it.
Yield is where everybody panics for no reason. Nobody out here runs the house straight off the well. The well fills a storage tank and a booster pump runs the house at full pressure, which is what the U of A's own well guide tells you to do when the yield isn't huge. Do the math. Even 3 gallons a minute, which is literally the state's definition of a struggling well, puts over 4,300 gallons a day into a tank. A normal Tucson household uses about 300.
And one more thing buyers miss constantly. The 100-year rule doesn't apply to every piece of dirt. Under state law a "subdivision" is six or more parcels under 36 acres each. 36 acres and up sits outside that definition, and that's exactly why so much of the ranch country down here is cut at 36 and sold on wells. It's not a coincidence.
The 100-year rule, and where it's actually paused
You've probably read that Arizona stopped approving new subdivisions on groundwater. True, but read where. That happened in the Pinal Active Management Area in 2021 and the Phoenix AMA in 2023. Nothing like that has been done for the Tucson AMA, which runs from Marana down past Green Valley. Down here the program still runs on the published criteria: 100 years of physical, legal and continuous availability, water quality, financial capability, plan consistency, and a 1,000 foot depth-to-water limit.
Two things happened this year worth knowing. In April a judge blocked ADWR's "unmet demand" rule, the one that had frozen approvals up in Phoenix. And ADWR is rebuilding its Tucson groundwater model, targeting 2027. If you're planning a subdivision south of town, that model is the thing to watch, not the Phoenix headlines.
There are three ways to make the 100-year showing: a certificate backed by CAGRD replenishment, a commitment from a designated water provider, or renewable supplies and storage credits you dedicate to the project. And the designated providers are already here. Sahuarita Water Company holds a 100-year designation. The proof is on the ground. Quail Creek got approvals for over 4,000 homes, and the whole town of Sahuarita, 34,000 some people, got built under the same program.
What's actually under the ground down here
Nobody puts this in a listing and it's honestly the strongest part of the whole story.
- The aquifer is federally settled. Interior's 2007 Statement of Findings locked in the Tohono O'odham settlement, the Asarco agreement, the FICO agreement and the San Xavier groundwater protection program under the 2004 Arizona Water Settlements Act. The fight over who owns the water in this basin got settled 20 years ago.
- The mine runs on river water. Asarco's Mission mine took rights to 10,000 acre-feet a year of tribal Colorado River water and cut its pumping to match, about 80% of what it uses, since 2009.
- So do the pecans. The orchards south of Sahuarita were the biggest pumper in the basin, something like 25,000 acre-feet a year. They switched to CAP water in 2020 through a $17.1 million pipeline they paid for themselves. And Twin Buttes mine shut down in 1994.
- Recharge is real, you can measure it. The Pima Mine Road recharge project, Project Renews and a 22,000 acre-foot-a-year groundwater savings facility are all running in the corridor, and USGS says subsidence has slowed way down and levels are actually coming up a little near the recharge sites.
What to check before you buy anything
- Any well's depth, level and yield - ADWR's well registry. Every registered well in the state is in there.
- Whether the parcel sits inside a designated provider's service area, or under a certificate - Pima County's assured water supply map.
- The state public report on any parceled land you're buying. It has to spell out the water situation in plain English. Read it before your earnest money goes hard, not after.
The questions people actually type into Google
Is Tucson running out of water? No. Three sources, unused river water banked underground, and the water director has said the river shortage isn't expected to hit the Tucson basin. The open question is how much river water Arizona keeps after 2026, and that's a city planning problem, not a today problem for a rural well.
Where does southern Arizona get its water? Colorado River water through the CAP canal, treated reclaimed water, and groundwater. South of Tucson the two biggest users, the Mission mine and the pecan orchards, moved most of their demand over to river water, and three recharge projects are putting water back in.
Can I drill a well on land south of Tucson? On most rural acreage, yes. Domestic well up to 35 gallons a minute is exempt. File the notice with ADWR, use a licensed driller, register it. No certificate, no hydrology study.
Does the Arizona groundwater pause apply here? No. The pauses were Pinal and Phoenix. Tucson's AMA never got one, and a judge blocked the Phoenix rule in April 2026 anyway.
What should I check before I buy? The well records in the ADWR registry, whether the parcel is in a provider's service area on the county map, and the state public report on any parceled land. All three are linked above.
If you're looking at acreage south of Tucson and water is the thing holding you up, send me the parcel number. I'll pull the well records and the county map and tell you what's there. No pitch, just the answer.
Hudson Robison
Designated Broker, The Broker Reserve · 480.313.3234 · hudson@thebrokerreserve.com
Sources
- A.R.S. § 45-454, exempt wells · ADWR, exempt wells · S.2063, 3-gpm threshold
- Statutory "subdivision" definition, Dunaway Law Group
- ADWR, Assured and Adequate Water Supply overview
- Snell & Wilmer on the Phoenix AMA pause · Arizona Daily Star, 1,000-ft limit
- WRRC, Pinal AMA determination (2021)
- Arizona Mirror, rule blocked April 2026 · ADWR Tucson groundwater model
- ADWR list of designated providers · Sahuarita Water Company
- Pima County assured water supply map and CAGRD
- Arizona Daily Star, Quail Creek approvals · Sahuarita population
- 72 Fed. Reg., Statement of Findings (2007) · S.437, Arizona Water Settlements Act
- Arizona Daily Star, Mission mine on CAP (2009) · Arizona Daily Star, pecan pipeline (2020) · Freeport-McMoRan, Twin Buttes
- University of Arizona Cooperative Extension, AZ1581 · Arizona Daily Star, household use
- KGUN 9, the future of water for Tucson and Marana residents · NPR, Tucson's banked Colorado River water · AZPM, what Colorado River cuts could mean for Tucson's water supply (March 2026)
- Town of Sahuarita, Pima Mine Road Recharge · Community Water Co., Project Renews · Green Valley Pecan, groundwater savings facility · Arizona Daily Star, USGS subsidence findings
Pulled from the public sources linked above, believed reliable but not guaranteed. Nothing here is a guarantee of water availability, well yield or any regulatory outcome. Assured water supply determinations are made by the Arizona Department of Water Resources, not by me. Equal Housing Opportunity.
