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Which report this is
This page summarizes Tucson Water's 2025 Annual Water Quality Report for the main system, which covers testing from January 1 to December 31, 2025. It's the newest report Tucson Water has published. Tucson Water publishes these reports each June.1,2 It applies to Tucson Water's main system only. Tucson Water's small isolated systems, and other utilities such as Metro Water, publish their own reports.2
Tucson Water serves over 244,000 households and businesses in the main system. It says about 78% of the water it delivers each year is recharged Colorado River (CAP) water recovered through wells, and about 22% comes from its Central Well Field.1 The report says the system had no health-based MCL or missed-monitoring violations.1
Key numbers from the 2025 report
| What | 2025 result | Notes |
|---|---|---|
| Hardness | No published figure | Tucson Water lists hardness among the things it monitors, but the 2025 report gives no number. Its parameter guide calls Tucson's water "hard to very hard" (180+ mg/L is "very hard").1,4 |
| Total dissolved solids (TDS) | No published figure | Listed as monitored, with no number given.1 EPA's non-enforceable taste guideline is 500 mg/L.6 |
| Disinfectant residual | Chlorine: annual average 1.0 ppm; monthly averages 0.94–1.07 ppm | Limit (MRDL) is 4 ppm. Tucson Water adds about 1 ppm of chlorine at well sites, reservoirs and other facilities and takes 248 routine chlorine samples a month. The report describes chlorine disinfection and lists no chloramine.1 |
| Sodium | 22.4–70.4 ppm (highest 70.4) | No federal limit. Source listed as erosion of natural deposits.1 |
| Arsenic | Highest 8.8 ppb (range ND–8.8) | Limit 10 ppb. No violation.1 |
| Nitrate | Highest 6.7 ppm (range 0.25–6.7) | Limit 10 ppm. The report advises anyone caring for an infant to ask a health care provider for advice if nitrate is above 5 ppm.1 |
| Fluoride | Highest 0.80 ppm (range 0.13–0.80) | Limit 4 ppm.1 |
| Uranium | Highest 16 ppb (range ND–16) | Limit 30 ppb.1 |
| Total trihalomethanes (TTHM) | 13.6 ppb highest locational running annual average (samples 1.8–26.8) | Disinfection byproduct. Limit 80 ppb.1 |
| Haloacetic acids (HAA5) | 1.3 ppb highest locational running annual average (samples ND–2.1) | Disinfection byproduct. Limit 60 ppb.1 |
| Lead | 90th percentile 0.65 ppb; 0 samples above the action level | Action level 15 ppb. Most recent sampling year listed: 2023.1 |
| Copper | 90th percentile 0.135 ppm; 0 samples above the action level | Action level 1.3 ppm. Sampling year 2023.1 |
| pH | No published figure | Listed as monitored, with no number given.1 |
ppm = parts per million (mg/L). ppb = parts per billion. ND = not detected. "Highest" is the highest result the report lists for 2025.
What isn't published
Hardness and TDS: the report lists both among the things Tucson Water tests, but it doesn't give a figure for either.1 The 2024 report didn't either.3 We don't fill the gap with numbers from other websites. For a reading near your home, use the City of Tucson's water quality map,5 or ask a dealer to test your tap. You can also see Tucson hardness by ZIP for which utility's figures apply where you live.
PFAS
Tucson Water completed EPA's UCMR5 study in 2025: 29 PFAS plus lithium, from 162 samples. The report says perfluorobutanoic acid (PFBA) was detected once at one well site, giving 1 PFAS detection out of 4,698 PFAS parameters analyzed. All other PFAS results were below the detection limit. Lithium was also detected.1
2024 vs. 2025
| What | 2024 report | 2025 report |
|---|---|---|
| Sodium | 24.5–40.8 ppm | 22.4–70.4 ppm |
| Chlorine (annual average; monthly range) | 1.0 ppm (0.96–1.14) | 1.0 ppm (0.94–1.07) |
| Arsenic (highest) | 6.64 ppb | 8.8 ppb |
| Nitrate (highest) | 7.2 ppm | 6.7 ppm |
| Fluoride (highest) | 0.59 ppm | 0.80 ppm |
| Hardness | No published figure | No published figure |
| TDS | No published figure | No published figure |
From the 2024 and 2025 main-system reports.1,3
What this means for home treatment
- Scale: Tucson Water calls its water "hard to very hard",4 but with no published number, test your tap before sizing a softener. See Tucson softener cost.
- Taste and dissolved minerals: under-sink reverse osmosis is the system type where TDS reduction is a required NSF/ANSI 58 claim. Check a unit's listing for anything else it's certified to reduce.7 See Tucson RO cost and why CAP water tastes the way it does.
- Chlorine taste: carbon filters certified to NSF/ANSI 42 target chlorine taste and odor.8
- Sodium: Tucson Water notes that softeners usually trade hardness minerals for sodium.4 If you watch sodium, ask about RO for drinking water.
Frequently asked questions
What is the hardness of Tucson water?
Tucson Water's 2025 Annual Water Quality Report doesn't publish a hardness figure. Tucson Water's parameter guide describes its water as "hard to very hard" (180+ mg/L is very hard). The City's online water quality map shows readings from sample points near your address.
Does Tucson use chlorine or chloramine?
The 2025 report describes chlorine disinfection and lists chlorine at an annual average of 1.0 ppm (monthly averages 0.94–1.07 ppm), against a limit of 4 ppm. It doesn't list chloramine.
How much sodium is in Tucson water?
Tucson Water's 2025 report lists sodium at 22.4 to 70.4 ppm.
More Tucson water guides: Tucson water hardness by ZIP · 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 2025 Annual Water Quality Report, Main System (PWS AZ0410112), PDF
- Tucson Water: 2025 Annual Water Quality Reports (archive page)
- Tucson Water 2024 Annual Water Quality Report, Main System, PDF
- Tucson Water: water quality parameter explanation table
- City of Tucson: interactive water quality lookup
- 40 CFR 143.3: secondary maximum contaminant levels
- NSF: NSF/ANSI 58 reverse osmosis systems
- NSF: NSF/ANSI 42, 53 and 401 filtration standards
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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.