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Which report this is
This page summarizes the City of Mesa's 2025 Water Quality Consumer Confidence Report, issued in 2026, which reflects testing done in 2025. It's the newest report Mesa has published.1,2 It covers City of Mesa water customers only.
Mesa is split into three zones. The City Zone gets Salt and Verde River water treated at the Val Vista plant, about 40% of 2025 deliveries. The Eastern and Southern Zones get Colorado River (CAP) water from the Brown Road and Signal Butte plants, about 52%. City wells supplied about 4%, and Eastern and Southern wells another 4%.1 The report's map shows which zone you're in.
Key numbers from the 2025 report
| What | Result in the 2025 report | Notes |
|---|---|---|
| Total hardness | 6.6–433 ppm (0.4–25 grains per gallon); zone averages about 12 gpg (City Zone) and 16 gpg (Eastern and Southern Zones) | Sampled 2025. Mesa says groundwater share and well minerals explain the wide range.1 |
| Total dissolved solids (TDS) | 190–970 ppm | Sample year 2022, the most recent listed. EPA's non-enforceable guideline is 500 ppm.1,3 |
| Disinfectant residual | Chlorine: highest running annual average 0.65 ppm; samples 0.02–2.04 ppm | Limit (MRDL) is 4 ppm. The report lists no chloramine.1 |
| Chlorine dioxide | Highest 150 ppb (<20–150) | Used at the Val Vista and Brown Road plants. Limit 800 ppb.1 |
| Sodium | 45–212 ppm | No federal limit.1 |
| pH | 6.60–8.51 | EPA guideline 6.5–8.5.1 |
| Calcium | 2.6–103.7 ppm | Sampled 2025.1 |
| Magnesium | 0.19–43 ppm | Sample year 2022.1 |
| Arsenic | Highest 8.8 ppb (0.8–8.8) | Limit 10 ppb.1 |
| Nitrate | Highest 8.99 ppm (ND–8.99) | Limit 10 ppm.1 |
| Fluoride | Highest 1.11 ppm (ND–1.11) | Sample year 2021. Limit 4 ppm. Mesa has fluoridated since 1999.1 |
| Total trihalomethanes (TTHM) | 57 ppb highest locational running annual average (ND–64.09) | Disinfection byproduct. Limit 80 ppb.1 |
| Haloacetic acids (HAA5) | 25 ppb highest locational running annual average (ND–19.6) | Disinfection byproduct. Limit 60 ppb.1 |
| Bromate | 4.0 ppb highest running annual average (2.8–7.0) | Disinfection byproduct. Limit 10 ppb.1 |
| Lead (2024 sampling) | 90th percentile 5.01 ppb; 1 sample above the action level; range 0.13–15.32 | Action level 15 ppb. Sampled every three years.1 |
| Copper (2024 sampling) | 90th percentile 0.17 ppm; 0 above the action level | Action level 1.3 ppm.1 |
ppm = parts per million (mg/L). ppb = parts per billion. ND = not detected. Hardness, TDS, pH, calcium, magnesium and sodium come from the report's "Other Parameters of Interest" table.1
What isn't published
The report gives zone averages for hardness but no average for TDS or sodium. Its TDS range is from 2022 sampling, not 2025.1 There's no published figure by ZIP code or street. For a reading at your tap, test it or ask a dealer to.
Correction
This site used to describe Mesa's hardness as "12 to 22 grains per gallon", citing a City of Mesa web page that is no longer online. We now use the figures in the 2025 report instead.
What this means for home treatment
- Scale: Mesa suggests starting a softener at 16 gpg and adjusting.1 See Mesa softener cost, hard water in Mesa and softener installation in Mesa.
- TDS and taste: TDS reduction is a required claim for RO systems certified to NSF/ANSI 58. Check a unit's listing for anything else it's certified to reduce.4
- Chlorine taste: carbon filters certified to NSF/ANSI 42 target chlorine taste and odor.5
- Sodium: tap water already carries 45–212 ppm. A salt-based softener adds more, so ask about RO for drinking water if that matters to you.
Frequently asked questions
How hard is Mesa water?
Mesa's 2025 Water Quality Report says City Zone water averages about 12 grains per gallon and Eastern and Southern Zone water averages 16 gpg. Individual samples ranged from 0.4 to 25 gpg (6.6 to 433 ppm).
What should I set my water softener to in Mesa?
The City of Mesa recommends setting your softener at 16 gpg and then adjusting it to suit your needs and preference. A test of your own tap gives a better number.
What is the TDS of Mesa tap water?
Mesa's 2025 report lists total dissolved solids of 190 to 970 ppm, from 2022 sampling. EPA's non-enforceable secondary guideline is 500 ppm.
Does Mesa use chlorine or chloramine?
Mesa's 2025 report lists chlorine, with a highest running annual average of 0.65 ppm (samples 0.02 to 2.04 ppm) against a limit of 4 ppm. Chlorine dioxide is also used at two treatment plants. The report doesn't list chloramine.
How much sodium is in Mesa water?
Mesa's 2025 report lists sodium at 45 to 212 ppm.
More water quality reports: Chandler · Gilbert · Scottsdale · Phoenix · Tucson · Mesa water treatment pros
Sources
- City of Mesa 2025 Water Quality Report (Consumer Confidence Report, issued 2026), PDF
- City of Mesa: Water Quality page (current report)
- 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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