Water hardness in Duartina
80 mg/L moderately hard
Tap water in Duartina is moderately hard: 80 mg/L (4.7 gpg · 4.5 °dH · 8 °fH).
Source: Ministério da Saúde, SISAGUA – controle semestral (Companhia De Saneamento Basico Do Estado De Sao Paulo), CC BY-ND 3.0 (2026) · data checked 2026-10-20
Duartina, in São Paulo state, is supplied by Companhia De Saneamento Basico Do Estado De Sao Paulo. The Ministry of Health reports 80.0 mg/L hardness (2026), which is moderate. Kettles and showerheads may show some scale over time.
Portaria GM/MS nº 888/2021 sets a maximum of 300 mg/L CaCO₃ for total hardness (dureza total); operators report it in mg/L to SISAGUA.
Water data
| Total hardness | 80 mg/L |
|---|---|
| Utility | Companhia De Saneamento Basico Do Estado De Sao Paulo |
How Duartina compares
- Tap water in Duartina is 88 % harder than the median of the 1915 cities we track in Brazil (43 mg/L).
- By hardness it ranks 359 of 1915 in Brazil (1 = hardest); 81 % of these cities have softer water.
- In São Paulo it is number 82 of 530 cities; the regional median is 42 mg/L.
- Nearest city with clearly softer water: Piratininga, 24 km away (42 mg/L).
- Nearest city with clearly harder water: Oriente, 75 km away (125 mg/L).
Ranking of the hardest and softest water in Brazil →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Duartina
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Duartina water hard or soft?
It is moderately hard: 80 mg/L as CaCO₃ (4.7 gpg, 4.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Duartina safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Portaria GM/MS nº 888/2021 sets a maximum of 300 mg/L CaCO₃ for total hardness (dureza total); operators report it in mg/L to SISAGUA.
How many grains per gallon is Duartina water?
4.7 gpg, equal to 4.5 °dH, 8 °fH or 80 mg/L calcium carbonate.
What dishwasher salt setting should I use in Duartina?
For 80 mg/L (4.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Duartina?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Ministério da Saúde, SISAGUA – controle semestral (Companhia De Saneamento Basico Do Estado De Sao Paulo), CC BY-ND 3.0 (2026). Method: figure published by the water supplier. Ministério da Saúde, SISAGUA – controle semestral (Companhia De Saneamento Basico Do Estado De Sao Paulo), CC BY-ND 3.0 · Outdated figure? Tell us