How deep do you have to drill a well in Arizona?

The aquifer (the underground layer of rock and sand that holds water) and the water table (the depth at which the ground is saturated) beneath your land set how deep a well has to go, not a code minimum. Arizona has no required depth for a water well. A well is drilled only as deep as it has to go to reach enough water. Most domestic wells in the state land somewhere between 100 and 800 feet, and in deep desert basins, some go past 1,000 feet. Two homes a mile apart can need very different depths. Because water levels shift over time and vary lot by lot, confirm the likely depth for your specific parcel with a licensed well driller before you budget. These are general ranges, not a guarantee for your land.

Why there is no single answer to well depth

Well depth has no fixed number because you are chasing water, not a code requirement. The drill goes down until it hits a water-bearing layer that can supply the home, then a bit further to set the pump below the water level. How deep that is comes down to geology. In a valley with a high water table, you might hit good water at 150 feet. On a ridge or in a deep basin, the same water might sit 600 or 800 feet down. The land sets the depth, not a rule.

Arizona's geography makes this swing wide. The state sits on a series of basins and ranges, and groundwater collects in the basins. Rio Verde Foothills, the unincorporated area northeast of Scottsdale, is a good example of a place where depths vary sharply from lot to lot and water can sit deep. Areas closer to rivers and historic floodplains often have shallower water. Long-term pumping and drought also pull the water table down over the years, so a depth that worked for a neighbor decades ago may be too shallow today.

The best way to estimate your own depth is local well data. The Arizona Department of Water Resources (ADWR) keeps a public record of registered wells, including their depth and the depth to water. A licensed driller will pull the records for nearby wells on your road before quoting, because those neighbors are the closest thing to a preview of what your drill will find. That data, not a rule of thumb, is what sets a realistic depth and budget.

What sets the depth and cost of your well

The depth of your well is set by four things: the aquifer, the water table, how much water you need, and where the pump has to sit. Each one pushes the final number up or down, and together they drive both how deep you drill and what it costs.

• The aquifer depth. This is the big one. A shallow, productive aquifer means a shorter, cheaper well. A deep basin aquifer means a long, expensive one.
• The water table. The pump has to sit well below the standing water level so it keeps drawing even when the level drops in summer or in drought. That adds depth beyond the point where water first appears.
• Water demand. A single home needs less flow than a home plus irrigation, livestock, or a second dwelling. A driller may go deeper to reach a layer that yields enough gallons per minute.
• Well yield. If the first water-bearing layer is weak, the driller keeps going to find a stronger one, which adds depth.

Depth drives cost because most wells are priced by the foot for drilling and casing, plus the pump and electrical at the end. A shallow well of a few hundred feet costs far less than one past 800 feet. This is why a firm number only comes after a driller studies your parcel. Treat any range you read online as a starting point and get a per-foot quote based on local records. For how a well fits the larger rural-building picture, see how to get water to a home in Rio Verde Foothills.

Permits, drillers, and the exempt well rule

Before any drilling starts, Arizona requires you to file a notice with the state and use a licensed driller. ADWR rules are clear on both points. You must file a Notice of Intent (NOI) to Drill with ADWR before a new well is drilled, deepened, or modified. And the work has to be done by "a well driller licensed in the State of Arizona," or by a single-well licensee drilling one exempt well on their own property. You cannot legally drill a water well yourself without that license.

The most common home well is an exempt well. Under A.R.S. 45-454, an exempt well is a small-capacity well with a pump rated at no more than 35 gallons per minute, used for domestic, stock, or limited non-irrigation purposes. Exempt wells are easier to permit because they fall outside the heavier groundwater-rights rules that govern large pumping. For a typical single home, the exempt well is the standard path. To go beyond that capacity, or to pump inside certain managed areas, you face additional ADWR review.

Two more details matter. First, your lot may need a registered well and a recorded location before a county will approve a building permit for a rural home, because the home needs a proven water source. Second, well and septic spacing rules apply, since a well has to sit a set distance from a septic system to protect the water. We cover that in how close can a well be to a septic system in Arizona, and the filing itself in what is an ADWR Notice of Intent to drill a well.

What to do if your well runs dry

If a well runs dry, you usually have three options: deepen the existing well, drill a new deeper one, or change how you get water. A dry well rarely means the land has no water at all. More often the water table has dropped below the pump, or below the bottom of the well, after years of drought and pumping. The fix depends on how much deeper the water has gone.

Here are the common paths, roughly cheapest to most involved:

• Lower the pump. If there is still water in the well but the level fell below the pump, a driller can sometimes reset the pump deeper at modest cost. This is the first thing to check.
• Deepen the existing well. If the well bottom is now above the water, a driller can deepen the same borehole to chase the lower water table. You file an NOI to deepen, the same as a new well.
• Drill a new well. If the existing well cannot be saved, you drill a new, deeper well, often in a better-studied spot using current local data.
• Switch to hauled water or a shared source. Some rural owners, especially in parts of Rio Verde Foothills, rely on hauled water stored in a tank instead of a private well. See how to get water to a home in Rio Verde Foothills and what is a shared well agreement in Arizona.

A dry well is a real risk on rural Arizona land, so plan for it before you buy or build. Ask the seller for the well log and the most recent water-level reading, check ADWR records for nearby wells, and budget a cushion in case the driller has to go deeper than the neighbors did. Because water tables move and vary so much by location, confirm current local depths and well costs with a licensed Arizona driller before you commit to a parcel or a budget.

How Jematell Homes helps

We plan water and wastewater early so they never stall your permit. We would rather answer your questions before you build than after, so get in touch any time.

Sources

• Arizona Department of Water Resources: Well Drilling in Arizona
• Arizona Department of Water Resources: Well Forms and Applications
• A.R.S. 45-454 (Exemption of small non-irrigation wells; 35 gpm)