A.R.S. 45-454 defines Arizona's exempt well. A well whose pump moves 35 gallons per minute or less, used for the home or stock watering, can pump groundwater without a full water right, even inside an Active Management Area. Limits still apply, including a 100-foot rule near a city water system and required drilling paperwork.
This is a government work (Arizona statute, administrative rule, or city ordinance) in the public domain. Always confirm the current official text at the source before relying on it.
Arizona controls how much groundwater people pump. The control is tightest inside the state's Active Management Areas. Phoenix sits inside one of them. One narrow exception to that control is the exempt well. A.R.S. 45-454 defines it. A small well used for the home can pump water without a full groundwater right. This page explains what makes a well exempt, and the limits that still apply.
What makes a well "exempt"
The key number is the pump size. A well counts as exempt when its pump is small and the water serves a non-irrigation use. Household (domestic) use and stock watering both count. The statute describes these as "wells having a pump with a maximum capacity of not more than thirty-five gallons per minute." So the ceiling is 35 gallons per minute. People often call these domestic wells. The legal term in the statute is exempt well.
Why the exemption matters
Inside an Active Management Area (AMA), you usually cannot pump groundwater without a grandfathered right or a permit. This is the state's way of protecting a shared water supply. The exempt well is a listed exception to that system. If your well meets the 35 gpm limit and serves the home, you do not need a full groundwater right to use it. That is the whole point of A.R.S. 45-454.
The limits that still apply
Being exempt does not mean "no rules." Several limits remain:
- The 100-foot rule. A new exempt well cannot go in too close to a water company or city system. The statute says "an exempt well otherwise allowed by this section may not be drilled on land if any part of the land is within one hundred feet of the operating water distribution system." If a provider's lines already reach your lot, a new well may be off the table.
- Withdrawal limits. The statute caps how much water some exempt wells may pump each year. The cap depends on when the well was drilled and where it sits.
- Paperwork. You still must file a Notice of Intention to Drill before the work, and a completion report after.
What this means for you
On the Phoenix fringe or in rural Maricopa County, an exempt well can be a real option for a single home. But the 35 gpm cap sets the ceiling. That flow is plenty for a house and a yard. It is not enough for farming or a large commercial draw. And if city water already runs past your property, the 100-foot rule may block a new well.
Before any drilling starts, you file a Notice with the state under A.R.S. 45-596, and any old well on the lot must be capped or properly closed under A.R.S. 45-594. For the plain-English basics of living on well water, see well water system basics. If your pump keeps clicking on and off, see well pump short cycling. This page is general information, not legal advice. Confirm the current rule text and your own situation with the Arizona Department of Water Resources before you rely on it.
Keep Reading
- A.R.S. 45-594: Well Construction Standards and Capping an Open Well
- A.R.S. 45-596: Notice of Intention to Drill a Well
- Arizona Administrative Code R18-4-215: Backflow Prevention and Annual Testing
- AAC R18-9-A316: Septic Inspection When a Property Transfers
- How does a home well water system work in Arizona?
- Why is my well pump short-cycling (turning on and off rapidly)?