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Water in Maricopa County
What the state and federal record says about water across Maricopa County. Each figure names the agency it came from.
Can I drill a well here?
Yes, an exempt well, with Active Management Area limits on much of the county
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Outside an Active Management Area
An exempt well (35 gallons a minute or less) is allowed for any use but irrigation, with no yearly cap. Domestic use includes growing plants on under two acres.
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Inside an Active Management Area
An exempt well is allowed, but use other than household and stock watering is capped at 10 acre-feet a year.
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Near a city water main, in an older AMA
No exempt well if any part of the land is within 100 feet of a designated city provider's water mains, unless ADWR grants an exemption. The 100 feet is a survey question.
- Active Management Areas here: Phoenix AMA, Pinal AMA.
- Every well needs a notice of intention to drill filed with ADWR and a licensed driller. On five acres or less the county health authority also signs off the site plan, and no well may sit within 100 feet of a septic system.
What has actually been permitted in Maricopa County
- 4,419exempt wells registered since 2015
- 5,019production wells of every kind since 2015
- 460feet, the typical exempt well depth
- 200feet down to water, typically
ADWR wells registry Decided by: ADWR, on the notice of intention to drill.
- 50,940 Wells on record across 9,283 square miles
- 570 ft Well depth middle value across 2,647 of 9,283 square miles
- 246 ft Depth to water middle value across 294 of 9,283 square miles
Point at any square mile to read what is on it. Hover the maps below to compare them.
Maricopa County by the square mile
Each figure below is one number for the whole county. The map places the same records on the ground, square mile by square mile.
Wells on record. Every well ADWR has a record of, exempt and non-exempt together.
- none on record (bare ground)
- up to 1
- 2
- 3 to 4
- 5 to 10
- 11 to 40
- over 40
9,283 surveyed sections, drawn 3 by 3 miles to a square. The shading is scaled against every county in Arizona, so a color means the same thing on any of these pages. The outline is the county boundary from the Census Bureau: ground inside the line and outside the shading is ground nobody has drilled, filed on or addressed. Aerial imagery is the USGS National Map.
Water rights here are still being decided in court
100% of the county falls inside a general stream adjudication that has run for decades and is not finished. Until it ends, who holds what is formally unsettled.
Arizona general stream adjudications 1 of 14 counties
100% here 1st of 14 One bar per Arizona county from lowest to highest. Point at one to name it.
A lot of well registrations here have been cancelled
32% of well records are cancelled, against 20% in the median county. A cancelled registration is not a well you can use.
ADWR wells registry 1 of 15 counties
32% here 1st of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
Water systems here are under enforcement
18% of the county is served by a system with a formal EPA or ADEQ enforcement action on record, against 3% in the median county. An enforcement action is the step after a violation that was not fixed.
EPA Safe Drinking Water Information System 1 of 15 counties
18% here 1st of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
Wells here have to go a long way down
The typical well is 570 feet deep, against 332 ft in the median county, across 50,940 wells on record. Drilling is priced by the foot and the casing with it, so depth is the first line of any estimate for putting water on raw land, and it is the number a seller is least likely to volunteer.
ADWR wells registry 2 of 15 counties
570 ft here 2nd of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
A lot of this county is in a mapped floodplain
39% of the county intersects a FEMA special flood hazard area, against 25% in the median county. In Arizona that is usually a wash rather than a river, dry for most of the year and the reason the insurance is required anyway.
FEMA National Flood Hazard Layer 2 of 15 counties
39% here 2nd of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
Water sampled here comes back over a federal limit more often than it should
11.5% of groundwater samples in this county exceeded a federal drinking water standard, against 4% in the median county, across 49,500 samples. In Arizona the usual culprit is arsenic, which is natural, invisible, and a treatment cost rather than a reason not to buy.
Water Quality Portal (USGS and EPA) 2 of 15 counties
11.5% here 2nd of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
Much of this county is inside an Active Management Area
53% of the county sits in Phoenix AMA. Inside an AMA the state limits new groundwater pumping and a subdivision must prove a hundred-year assured water supply before it can sell lots. Outside one, almost none of that applies, and which side of the line a property falls on changes what can be built there.
ADWR Active Management Areas 3 of 9 counties
53% here 3rd of 9 One bar per Arizona county from lowest to highest. Point at one to name it.
A lot of this county is within five miles of a federal cleanup site
11% of the county lies within five miles of a Superfund site. Five miles is proximity rather than contamination, and it is the distance at which a groundwater plume stops being somebody else's problem.
EPA Superfund national priorities list 3 of 13 counties
11% here 3rd of 13 One bar per Arizona county from lowest to highest. Point at one to name it.
The water here stands a long way below the surface
The water table sits 242 feet down in the typical square mile. That is not the depth of the hole, it is where the water stands in it, and it sets the pump, the lift and the power bill for as long as the well runs.
ADWR groundwater level change 4 of 15 counties
242 ft here 4th of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
A lot of this county is land with nothing built on it
38% of the county holds parcels with no situs address, meaning no building with a number on the door. This is raw land country, which is the market, and it also means few neighbours to share a road, a line or a well with.
County assessor parcel records 4 of 15 counties
38% here 4th of 15 One bar per Arizona county from lowest to highest. Point at one to name it.
Ground here is prime farmland, but only if it is irrigated
33% of sections carry soil the USDA classes as 'prime farmland if irrigated'. The qualifier is the whole sentence: the soil is excellent and the classification depends on water reaching it.
USDA SSURGO soil survey 4 of 10 counties
33% here 4th of 10 One bar per Arizona county from lowest to highest. Point at one to name it.
A court has already adjudicated the water over part of this county
8.9% of this county sits inside a decreed area, under 5 mapped court decrees. An adjudication is a court deciding who owns what water on a stream and in what order, and once entered it governs. On an adjudicated stream the decree, rather than a well permit, is what says whether there is water to use.
ADWR decreed area boundaries 1 of 10 counties
8.9% here 1st of 10 One bar per Arizona county from lowest to highest. Point at one to name it.
The land here is sinking where the aquifer was drawn down
2,021 mapped subsidence features and no confirmed fissures yet. Subsidence is what precedes a fissure, and it is worth knowing about before it becomes one.
AZGS earth fissure and subsidence mapping 1 of 9 counties
2,021 here 1st of 9 One bar per Arizona county from lowest to highest. Point at one to name it.
Ground here has cracked open where the water was pumped out
507 confirmed earth fissures and 2,021 mapped subsidence features. Fissures open when an aquifer is drawn down and the land above settles unevenly. They swallow fences, roads and foundations, and no ordinary policy covers them.
507 here The bar is the whole county and the fill is this county's share.
Buying here can come with a CAGRD bill attached
3.9% of the county is inside a CAGRD service area. Membership means an annual charge that replenishes the groundwater a property pumps, it runs with the land, and it rises.
3.9% here The bar is the whole county and the fill is this county's share.
The irrigation water here is already spoken for
20,300 grandfathered irrigation rights are recorded in this county. Inside an AMA, ground that was already being irrigated in 1980 kept the right to go on doing it and no new irrigation right can be created. New ground does not get water by asking for it.
20,300 here The bar is the whole county and the fill is this county's share.
This county is being platted into subdivisions
41,419 platted subdivisions are recorded here. Inside an AMA each one had to prove a hundred-year assured water supply before a lot could be sold; outside one, it did not, and the developer only had to disclose that fact.
41,419 here The bar is the whole county and the fill is this county's share.
For one parcel in Maricopa County
The figures above describe the whole county. The Land, Development and Rights reports answer for one parcel: what water conveys, whether a household well needs only a notice, and whether the county requires an adequate water supply to split it. Each answer gives the evidence within a mile and who decides.
Search an address in Maricopa County