Shizuoka
Shizuoka, Japan has an estimated water hardness of 80 ppm (mg/L as calcium carbonate), which is classed as moderately hard. Some mineral build-up is possible in heated appliances.
Shizuoka water hardness in every unit
| Unit | Reference estimate |
|---|---|
| mg/L or ppm (CaCO₃) | 80 |
| mmol/L | 0.8 |
| German degrees (°dH) | 4.48 |
| French degrees (°fH) | 8 |
| Clark degrees (°e) | 5.61 |
| Grains per US gallon (gpg) | 4.67 |
How the Shizuoka figure was derived
- Period covered: Not stated by the source
- Calculation: The source publishes a single typical figure and no range.
Where Shizuoka's water comes from
- Supplier: Shizuoka City Waterworks and Sewerage Bureau
- Source: Shizuoka City’s municipal water sources, which differ by area
- Official website: Shizuoka City
The City describes its tap water as moderately soft, with a hardness of about 80 mg/L that varies by water source. Shizuoka City: tap water quality (checked 2026-10-31).
How Shizuoka compares
With a reference estimate of 80 ppm, Shizuoka ranks 34th hardest of the 69 cities in our directory, 6 ppm above the directory median of 74 ppm. Among the cities in our directory in Asia, Nagoya is the softest at 19 ppm.
What moderately hard water means at home
Moderately hard water can leave light white deposits on kettle elements, taps and glassware over time. It is usually manageable with periodic descaling, and many households need no softening equipment at all.
Using a 80 ppm reading with your appliances
- Dishwasher: salt check manual; match the converted reading to your model. Use salt only as specified for the built-in softener.
- Coffee machine: descale when the manual or machine indicates; filter: use only a compatible filter specified by the manufacturer.
- Laundry: use the medium-water dose. Follow the product label for your load size.
- Kettle: Inspect for scale; follow the manual.
- Humidifier: For ultrasonic or impeller units, use low-mineral water such as distilled water. Empty and dry portable tanks daily; clean every third day. Follow manufacturer instructions.
Official manufacturer guidance
Use these references with your exact appliance model. They explain settings and maintenance, not the local water measurement. Source languages and model limits are shown; these are not affiliate links.
- De’Longhi Japan — ディナミカ ECAM35015BH：使い方・お手入れ (ja)
ECAM35015BH commercial coffee-machine page with a water-hardness checker listed and linked cleaning/descaling demonstrations. Model-specific, not a general household maintenance schedule.
- Panasonic Japan — 加湿機：サポート・お手入れ (ja)
Panasonic humidifier support and manual links. This manufacturer specifies fresh tap water for its products; do not substitute generic ultrasonic-humidifier advice for your model’s instructions.
(checked 2026-10-20).
Hardness alone does not determine maintenance frequency. How to match your reading to an appliance manual. Dishwasher settings by brand: find your setting. Thinking about a softener? Pros and cons and sizing. Kettles and coffee machines: descaling guide. Portable humidifier care: US EPA guidance.
Frequently asked questions
Do I need dishwasher salt in Shizuoka?
Check manual. Use salt only as specified for the built-in softener. Always follow your dishwasher manual.
How often should I descale a coffee machine in Shizuoka?
Descale when the manual or machine indicates. Hardness alone does not determine an interval: usage and appliance design also matter. Water filter: use only a compatible filter specified by the manufacturer.
Do I need a water softener in Shizuoka?
Usually not. Appliance settings and occasional descaling are normally enough, but a filter or softener is a personal choice if you dislike spotting.
Is hard water in Shizuoka safe to drink?
Water hardness is mainly an aesthetic and scale issue. The World Health Organization does not set a health-based guideline value for it. Hardness affects taste, scale and detergent use rather than drinking safety, and your utility is responsible for meeting drinking-water standards. If you have a specific health or dietary concern, ask your doctor.
How to check your own water
City averages are a starting point. To get your actual figure, check the linked source (Shizuoka City: tap water quality) and obtain a current report for your address from your water supplier, or dip a hardness test strip in a glass of cold tap water and read it against the chart. Strips usually report in °dH, gpg or ppm; enter the number into the Waterdial checker to convert it and see the matching appliance settings. Use a recent, correctly performed hardness test when a city estimate is too broad.
Source
Shizuoka City: tap water quality, checked 2026-10-31. Guidance is general; your appliance manual takes priority.
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