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No utility publishes hardness by ZIP code. Hardness depends on which utility serves your address and which wells or system feed it. This table doesn't invent a per-ZIP number. It shows which published utility figures could apply in each ZIP, so you know which report to trust.
For your exact address, use the City of Tucson's interactive water-quality map. It shows results from a nearby sample point, including grains per gallon.3 Or check the name on your water bill and use that utility's figure below.
The published figures
- Tucson Water (main system): classed "hard to very hard" (180+ mg/L is "very hard" on its scale).1 Its 2025 annual report doesn't publish a system-wide hardness number,2 so check the city's address map for a nearby reading.3 See the 2025 water quality report summary.
- Metro Water, Metro Main: Metro Water's 2025 hardness map for Metro Main shows 52 to 130 ppm (3.0 to 7.6 gpg), depending on which system serves the neighborhood. (Metro Water 2025 Metro Main hardness map)
- Metro Water, Metro Hub: Metro Water's 2025 hardness map for Metro Hub shows an average of 71 ppm (4.17 gpg). (Metro Water 2025 Metro Hub hardness map)
- Metro Water, Metro Southwest (Diablo Village): Metro Water's 2025 hardness map for Diablo Village shows an average of 57 ppm (3.4 gpg). (Metro Water 2025 Diablo Village hardness map)
- Metro Water, Metro Southwest (E&T): Metro Water's 2025 hardness map for E&T shows an average of 325 ppm (19.01 gpg). (Metro Water 2025 E&T hardness map)
- Metro Water, Metro Southwest (Lazy B): Metro Water's 2025 hardness map for Lazy B shows an average of 230 ppm (13.45 gpg). (Metro Water 2025 Lazy B hardness map)
Metro Water notes that its systems are interconnected in some areas, so water is blended and concentrations may vary.5
ZIP table
"In Tucson city limits" is the share of the ZIP's land inside the City of Tucson (Census 2020).7 Provider shares are the portion of the ZIP's area inside each provider's mapped service boundary (Pima County GIS, which maps every provider except Tucson Water).6 City limits and Tucson Water's service area are not the same thing.
| ZIP | In Tucson city limits | Metro Water area | Other mapped providers | Published figures that may apply |
|---|---|---|---|---|
| 85701 | 100% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85704 | 0% (outside city limits) | Metro Main: 54% | Town of Oro Valley: 12% Mesaland Water Co: 1% | Metro Water Metro Main: 52 to 130 ppm (3.0 to 7.6 gpg), depending on which system serves the neighborhood. Other mapped providers: no published figure on our site |
| 85705 | 75% | none | Flowing Wells ID: 24% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85706 | 76% | none | Ray Water Company: 18% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85707 | 99% | none | DMAFB Water System: 88% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85708 | 100% | none | DMAFB Water System: 98% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85709 | 100% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85710 | 100% | none | Halcyon Acres Water User Ass.: 2% Halcyon Acres Annex Water #2: 1% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85711 | 100% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85712 | 99% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85713 | 52% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85714 | 75% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85715 | 77% | Metro Hub: under 1% | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Metro Water Metro Hub: an average of 71 ppm (4.17 gpg). |
| 85716 | 98% | none | Winterhaven Water and Co: 2% U of A: 1% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85719 | 100% | none | U of A: 7% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85721 | 100% | none | U of A: 100% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85723 | 100% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85724 | 100% | none | U of A: 62% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85726 | 100% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85730 | 28% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85734 | 100% | none | Arizona State Prison: 24% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85735 | 0% (outside city limits) | Metro Southwest (Lazy B): under 1% | Thim Utility: 3% | Metro Water Lazy B: an average of 230 ppm (13.45 gpg). Other mapped providers: no published figure on our site |
| 85737 | 0% (outside city limits) | Metro Main: 4% | Town of Oro Valley: 51% Lago Del Oro Water Co: 9% | Metro Water Metro Main: 52 to 130 ppm (3.0 to 7.6 gpg), depending on which system serves the neighborhood. Other mapped providers: no published figure on our site |
| 85741 | 0% (outside city limits) | Metro Main: 52% | Town of Marana: 4% | Metro Water Metro Main: 52 to 130 ppm (3.0 to 7.6 gpg), depending on which system serves the neighborhood. Other mapped providers: no published figure on our site |
| 85742 | 0% (outside city limits) | Metro Main: 21% | Town of Oro Valley: 12% Town of Marana: 7% | Metro Water Metro Main: 52 to 130 ppm (3.0 to 7.6 gpg), depending on which system serves the neighborhood. Other mapped providers: no published figure on our site |
| 85745 | 32% | none | Lazy C Water Service: 3% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85747 | 69% | none | DMAFB Water System: 10% Spanish Trail Water Company: 10% Rincon Creek Water Co.: 2% Vail Water Company: 1% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Other mapped providers: no published figure on our site |
| 85748 | 52% | none | none mapped | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) |
| 85750 | 0% (outside city limits) | Metro Hub: 12% | none mapped | Metro Water Metro Hub: an average of 71 ppm (4.17 gpg). |
| 85756 | 55% | Metro Southwest (E&T): under 1% | Red Rock Utilities LLC: 5% DMAFB Water System: 3% Voyager Water Company: 1% | Tucson Water main system: "hard to very hard" (no system-wide number published; use the city's address map) (if you're a Tucson Water customer) Metro Water E&T: an average of 325 ppm (19.01 gpg). Other mapped providers: no published figure on our site |
| 85757 | 0% (outside city limits) | Metro Southwest (Diablo Village): 20% | none mapped | Metro Water Diablo Village: an average of 57 ppm (3.4 gpg). |
Missing data: we don't have published hardness figures for the other providers listed (for example Flowing Wells, Oro Valley, Marana or Davis-Monthan's system). If one serves you, check its annual water quality report. ZIPs not listed here are outside the Tucson coverage of our lookup.
Convert and set your softener
Divide mg/L (ppm) by 17.1 to get grains per gallon (Tucson Water's conversion).1 See how to set softener hardness.
Frequently asked questions
Does Tucson Water publish hardness by ZIP code?
No. No Tucson-area utility publishes hardness by ZIP code, and Tucson Water's 2025 annual report doesn't give a system-wide hardness number either. The City of Tucson's online water quality map shows readings from sample points near an address.
How do I know if I'm on Tucson Water or Metro Water?
Check the name on your water bill. Many Tucson-area ZIP codes are split between providers, so a ZIP code alone can't tell you.
How hard is Metro Water's water?
Metro Water's 2025 hardness maps show 52–130 ppm (3.0–7.6 gpg) across Metro Main, an average of 71 ppm for Metro Hub and 57 ppm for Diablo Village, and 230 ppm for Lazy B and 325 ppm for E&T.
More Tucson water guides: Tucson water quality report (2025) · Tucson Water vs. Metro Water hardness · Why CAP water tastes the way it does · RO vs. whole-house filter · Tucson softener cost · Tucson RO cost
Sources
- Tucson Water: water quality parameter explanation table
- Tucson Water 2025 Annual Water Quality Report (Main System)
- City of Tucson: interactive water quality lookup
- Metro Water: service area maps
- Metro Water: hardness, TDS and fluoride
- Pima County GIS: Water Provider Service Areas (except Tucson Water)
- US Census Bureau: 2020 ZCTA to place relationship file
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Get free quotesMoving to Tucson or Phoenix?
New to the area, including military families on a PCS move? Here's what the local water utilities publish, so you know what you're dealing with before you buy or rent treatment equipment.
- Tucson: find out who supplies your water first. Depending on the address (not just the ZIP code), it can be Tucson Water, Metro Water or another provider. The name is on the water bill (Pima County water provider service areas).
- Tucson Water calls its water "hard to very hard" and its 2025 report gives no single system-wide hardness number (parameter guide; 2025 report). Its online lookup shows readings from sample points near an address. See our Tucson hardness by ZIP table.
- Metro Water's 2025 hardness maps run from 3.0 gpg in parts of Metro Main (map) to an average of 19.01 gpg in E&T (map).
- Phoenix: the City of Phoenix's 2025 Water Quality Report lists hardness of 172–302 ppm, or 10–17.6 grains per gallon (2025 report). It doesn't publish hardness by ZIP code. Some Phoenix-area ZIPs are split between the City of Phoenix and other providers (ADWR service area map), so check your bill. Neighboring cities publish their own reports: Scottsdale, Mesa, Chandler, Gilbert. See Phoenix hardness by ZIP.
- Setting a softener or dishwasher: both use grains per gallon. Divide mg/L (ppm) by 17.1 (Tucson Water's conversion). A test of your own tap is more precise than a citywide range. See how to set softener hardness.