Hardness
Moderately hard average62mg/L as CaCO₃
average; range 8.1–112
USGS hardness classes
About 3.6 gpg. The range runs from soft to moderately hard; this report does not support treating every SF home as very hard.
2025
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Your local water, explained
San Francisco County Water Quality Report
One city and county. Confirm the water system before using its report.
San Francisco is a consolidated city and county, but a county label still does not identify every water system. Start with SFPUC’s San Francisco retail report, then use the city guide for its hardness and treatment context.
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Your water
Match the name on your water bill.
Check the supplier on your water bill. City and county boundaries can include several water systems.
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.
These are utility measurements, not a test at your tap or a current service advisory. Sources checked October 28, 2026
Choose the right utility report
The figures below are provider-specific. They are not a countywide average.
| Utility | Hardness | Hardness source |
|---|---|---|
| 62 mg/L as CaCO₃ · Moderately hard average | 2025 · average; range 8.1–112 |
Showing utility report
SFPUC — San Francisco retail system
2025 utility report; sampling years shown beside each result
Select this exact provider and supply system. A city, county or ZIP match alone does not confirm the water reaching your home.
Your water at a glance
See the amount, the comparison and what it means. “Below” refers to the stated benchmark, not zero risk.
Chloramine
Below the 4 mg/L limit2.6mg/L
highest running annual average; range <0.1–3.6
MRDL: 4 mg/L
Select filtration with documented chloramine performance at the flow your home needs.
2025
View source ↗TTHMs
Below the 80 ppb limit47µg/L (ppb)
highest locational annual average; range 12–65
MCL: 80 ppb
This is a distribution-system statistic, not a sample from your home.
2025
View source ↗HAA5
Below the 60 ppb limit37µg/L (ppb)
highest locational annual average; range 6–50
MCL: 60 ppb
Read byproducts using the report’s averaging basis.
2025
View source ↗Fluoride
Below California’s 2 mg/L limit0.7mg/L
treated-water average; range 0.5–0.8
California MCL: 2 mg/L
Uses treated-water results from the report footnote, not the separate source-water fluoride row.
2025
View source ↗Lead
Below the report’s action level4.9µg/L (ppb)
90th percentile; 50 sampled taps
Report action level: 15 ppb
No sampled tap exceeded 15 ppb. Your plumbing can affect your own result; below an action level is not a no-risk guarantee.
August 2024
View source ↗Arsenic
Cannot rate the levelNo numerical resultin the report summary
not listed as a result in the reviewed tables
Missing numerical data is not zero and does not establish an exceedance. Ask SFPUC for its detailed monitoring data.
2025
View source ↗PFAS
Below reporting limitsNot detected29 tested compounds
UCMR5 monitoring
Compound-specific reporting limits
A nondetect is not proof of zero. These historical utility tests do not measure your current tap.
2023–2024
View source ↗View Full Water ReportOpen the measured results, dates, comparisons and original utility report.
The numbers behind your report
Selected results with the original sampling dates and measurement basis. Open the utility report for every parameter, notice and footnote.
Open the complete utility report ↗
| What was measured | Reported amount | Sample year / source date | How to read it |
|---|---|---|---|
| Hardness | 62 mg/L as CaCO₃average; range 8.1–112 | 2025View source ↗ | Moderately hard averageAbout 3.6 gpg. The range runs from soft to moderately hard; this report does not support treating every SF home as very hard. |
| Chloramine | 2.6 mg/Lhighest running annual average; range <0.1–3.6 | 2025View source ↗ | Below the 4 mg/L limitSelect filtration with documented chloramine performance at the flow your home needs. |
| TTHMs | 47 µg/L (ppb)highest locational annual average; range 12–65 | 2025View source ↗ | Below the 80 ppb limitThis is a distribution-system statistic, not a sample from your home. |
| HAA5 | 37 µg/L (ppb)highest locational annual average; range 6–50 | 2025View source ↗ | Below the 60 ppb limitRead byproducts using the report’s averaging basis. |
| Fluoride | 0.7 mg/Ltreated-water average; range 0.5–0.8 | 2025View source ↗ | Below California’s 2 mg/L limitUses treated-water results from the report footnote, not the separate source-water fluoride row. |
| Lead | 4.9 µg/L (ppb)90th percentile; 50 sampled taps | August 2024View source ↗ | Below the report’s action levelNo sampled tap exceeded 15 ppb. Your plumbing can affect your own result; below an action level is not a no-risk guarantee. |
| Arsenic | No numerical result in the report summarynot listed as a result in the reviewed tables | 2025View source ↗ | Cannot rate the levelMissing numerical data is not zero and does not establish an exceedance. Ask SFPUC for its detailed monitoring data. |
| PFAS | Not detected 29 tested compoundsUCMR5 monitoring | 2023–2024View source ↗ | Below reporting limitsA nondetect is not proof of zero. These historical utility tests do not measure your current tap. |
| Bromate | 3.5 µg/Lhighest running annual average; range 1.9–4.1 | 2025View source ↗ | Below the 10 µg/L limit |
| Chromium-6 | 0.1 µg/Laverage; range ND–0.1 | 2025View source ↗ | Below the report’s 10 µg/L limit |
| Nitrate as nitrogen | ND mg/Laverage; range ND–0.4 | 2025View source ↗ | Reported range below 10 mg/LND means below the reporting limit, not zero. |
| Copper | 72 µg/L90th percentile; range ND–152 | August 2024View source ↗ | Below the 1,300 µg/L action level |
| Total dissolved solids | 95 mg/Laverage; range 24–197 | 2025View source ↗ | Below the report’s 1,000 mg/L benchmarkAn aesthetic measure; TDS alone cannot establish water safety. |
| Iron | 17 µg/Laverage; range <6–36 | 2025View source ↗ | Below the 300 µg/L aesthetic benchmark |
| Manganese | <2 µg/Laverage; range <2–2.7 | 2025View source ↗ | Below the 50 µg/L aesthetic benchmark |
| Chloride | 10 mg/Laverage; range <3–19 | 2025View source ↗ | Below the report’s 500 mg/L benchmark |
| Sodium | 18 mg/Laverage; range 3.1–29 | 2025View source ↗ | No MCL listed in this report |
| pH | 9.3 pH unitsaverage; range 9.0–9.7 | 2025View source ↗ | Alkaline waterpH is not hardness and does not by itself determine whether a softener is needed. |
In drinking water, ppm ≈ mg/L, ppb ≈ µg/L and ppt ≈ ng/L. Calculated hardness in grains per US gallon (gpg) = mg/L as CaCO₃ ÷ 17.118, rounded to one decimal. ND means below the reporting limit, not zero.
MCL is an enforceable contaminant limit; MRDL is a disinfectant limit. A PHG is a health goal, not the legal limit. Lead/copper action levels use system sampling percentiles, not a safe-tap threshold. TTHM/HAA5 comparisons use locational running annual averages.
PFAS results are compound-specific. Source monitoring, entry-point samples and tap tests are different. Notification and response levels in a utility report are not maximum contaminant levels; do not infer a compliance violation from a single value. EPA PFAS benchmarks and implementation ↗
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Source water. Predominantly Hetch Hetchy and Bay Area surface-water supplies, with small groundwater and purchased-water contributions. Source blends change.
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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More about your local water
What this means for your home
This county hub organizes the SFPUC San Francisco retail results and the linked city guide. Treasure Island has separate reporting. Wholesale SFPUC water supplied to another retailer also needs that retailer’s report. The 62 mg/L retail hardness average is not a measurement for every nearby address.
Related city reports
Different name on your water bill?
These local providers publish separate reports. Follow the matching utility link; the measurements above do not describe these systems.
A useful local question
Which San Francisco water report should I use?
Confirm the system that supplies your building. Use the San Francisco retail report for that system, and the separate report listed by SFPUC for Treasure Island when applicable. If you are outside the city, check your own retailer even when it buys SFPUC water.
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.
- SFPUC — San Francisco retail system ↗2025 utility report; sampling years shown beside each result
- USGS hardness classification
- EPA PFAS benchmarks and implementation
Sources checked October 28, 2026
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