Hardness
Hard average; wide range135.5mg/L as CaCO₃ · average
Range: 43.5–229 mg/L (2.5–13.4 gpg), from soft to very hard. Average: 7.9 gpg.
2025
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Your local water, explained
Houston Water Quality Report: Hardness & Chloramine
A hard average does not describe every Houston tap.
Houston Main System water averaged 135.5 mg/L hardness in 2025, but samples ranged from soft to very hard. Chloramine is used for disinfection. Match this report to your water bill, then use a tap hardness test to settle the softener question.
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Your water
Match the name on your water bill.
The report follows your water provider—not your ZIP code or county boundary.
Only the listed water system is summarized here. Choose “Other / not sure” if your bill shows a different supplier.
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Utility data is a starting point. It is not a test of your tap or a live advisory. Sources checked October 22, 2026
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Houston Water — Main System
2025 report; individual rows show sample year
Main System only. Houston’s report separately covers Kingwood, Willow Chase, District 73, District 82 and Belleau Woods; their results are not combined here.
Your water at a glance
See the amount, the comparison and what it means. “Below” refers to the stated benchmark, not zero risk.
Chloramine
Average below 4 ppm MRDL2.8ppm
Average; samples 0.04–4.8
Individual peaks and annual compliance averages are different.
2025
View source ↗TTHMs
Below 80 ppb MCL43.6ppb
Highest locational running annual average
2025
View source ↗HAA5
Below 60 ppb MCL40.8ppb
Highest locational running annual average
2025
View source ↗Fluoride
Below 4 ppm MCL0.71ppm
Maximum; average 0.11
2025
View source ↗Lead
Below 15 ppb action level5.1ppb
90th percentile; 0 sites over action level
A utility percentile is not a test of your faucet.
2025
View source ↗PFAS
Cannot assess high or lowNot quantified here
No compound-specific result used in this summary
No result shown does not mean absent.
2025 report
View source ↗Nitrate as nitrogen
Below 10 ppm MCL1.40ppm
Maximum in distribution samples
2025
View source ↗View Full Water ReportOpen the measured results, dates, comparisons and original utility report.
The numbers behind your report
Selected useful results—not a replacement for the utility’s complete report. Older measurements retain their original year.
Open the complete utility report ↗
| What was measured | Reported amount | Sample year / source date | How to read it |
|---|---|---|---|
| Hardness | 135.5 mg/L as CaCO₃ · average | 2025 | Hard average; wide rangeRange: 43.5–229 mg/L (2.5–13.4 gpg), from soft to very hard. Average: 7.9 gpg. |
| Chloramine | 2.8 ppmAverage; samples 0.04–4.8 | 2025 | Average below 4 ppm MRDLIndividual peaks and annual compliance averages are different. |
| TTHMs | 43.6 ppbHighest locational running annual average | 2025 | Below 80 ppb MCL |
| HAA5 | 40.8 ppbHighest locational running annual average | 2025 | Below 60 ppb MCL |
| Fluoride | 0.71 ppmMaximum; average 0.11 | 2025 | Below 4 ppm MCL |
| Lead | 5.1 ppb90th percentile; 0 sites over action level | 2025 | Below 15 ppb action levelA utility percentile is not a test of your faucet. |
| PFAS | Not quantified here No compound-specific result used in this summary | 2025 report | Cannot assess high or lowNo result shown does not mean absent. |
| Nitrate as nitrogen | 1.40 ppmMaximum in distribution samples | 2025 | Below 10 ppm MCL |
| Arsenic | 6.7 ppbMaximum at water plants | 2025 | Below 10 ppb MCL |
| Barium | 0.40 ppmMaximum | 2025 | Below 2 ppm MCL |
| Copper | 0.22 ppm90th percentile | 2025 | Below 1.3 ppm action level |
| Total dissolved solids | 260 ppmAverage; range 146–331 | 2025 | Below 500 ppm aesthetic guideline |
| Turbidity | 1.95 NTUHighest single measurement | 2025 | Report lists a treatment-technique violationSee the utility notice on page 9. |
ppm ≈ mg/L; ppb ≈ µg/L; ppt ≈ ng/L in drinking water. Hardness in gpg = mg/L as CaCO₃ ÷ 17.1. ND means not detected at the method’s reporting limit—not zero.
MCL is a maximum contaminant level. MRDL is a disinfectant limit. Lead/copper action levels use system sampling percentiles and are not a safe-tap threshold. TTHM/HAA5 compliance uses locational annual averages.
PFOA/PFOS comparisons use EPA’s 4 ppt values. Historical detections are not a present compliance finding; EPA assesses compliance using running annual averages. Rule implementation is being reviewed. EPA PFAS benchmarks and implementation ↗
Turn your report into a plan for your home.
Choose the system size, keep useful existing equipment, and review your filtration goals.
Source water. Main System water is a surface-water and groundwater blend. Its 2025 report describes 90.3% surface water and 9.7% groundwater.
Your provider needs its own report.
Continue with your home details for general filtration guidance. We will not use another utility’s numbers as your result.
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What this means for your home
Houston’s annual report covers six systems separately. This page summarizes Main System TX1010013 only. If your bill or service area points to Kingwood, Willow Chase, District 73, District 82 or Belleau Woods, use the corresponding system table in the original report.
A useful local question
Is Houston water hard enough to need a softener?
The Main System’s 2025 average was hard, but its range crossed four hardness categories. A current test at your home is the useful next step before including a softener for scale control.
Sources and methodology
We keep each utility’s results separate, show the reported sample year, and distinguish averages, maxima and tap-sampling percentiles. Hardness classifications use USGS ranges. Missing data stays unknown.
- Houston Water — Main System ↗2025 report; individual rows show sample year
- USGS hardness classification
- EPA PFAS benchmarks and implementation
Sources checked October 22, 2026
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