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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- 2Your home
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Your local water, explained
Harris County Water Quality Report & Provider Guide
One county does not mean one water supply.
Harris County has many water suppliers. Begin with the provider on your bill: this first report covers Houston Water’s Main System, while other Houston systems and municipal utility districts need their own reports.
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Your water → your home → your system
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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.
Confirm the provider on your bill, or choose “Other / not sure” to continue without a matched report.
Utility data is a starting point. It is not a test of your tap or a live advisory. Sources checked October 22, 2026
Choose the right utility report
The figures below are provider-specific. They are not a countywide average.
| Utility | Hardness | Hardness source |
|---|---|---|
| Hard average; wide range | 2025 |
Showing utility report
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.
Find My Water System →Private well? Start with a current water test.
A city report cannot establish a well’s water quality. Well-water treatment depends on your test results and site conditions.
Explore well-water systems →Email this report
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More about your local water
What this means for your home
A Houston mailing address is not enough to identify your water system. If your bill names a municipal utility district or a different system, choose “Other / not sure” and use that supplier’s report before making contaminant-specific treatment decisions.
Related city reports
A useful local question
Does the Houston report apply everywhere in Harris County?
No. Houston Main System, other Houston-operated systems, municipal utility districts and private wells are different water sources. Use this report only when the provider and system match your bill.
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
Your water → your home → your system
Turn your report into a plan for your home.
Choose the system size, keep useful existing equipment, and review your filtration goals.
Your homeFind my system →