Tap water hardness in Porto
We have published hardness data for 14 cities in Porto. The median is 98 mg/L; the hardest water is in Amarante (100 mg/L), the softest in Baião (26 mg/L).
0 % of these cities have hard or very hard water (over 120 mg/L).
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Cities in Porto, hardest first
| mg/L | mg/L | ||
|---|---|---|---|
| Amarante | 100 | 100 | moderately hard |
| Fânzeres | 100 | 100 | moderately hard |
| Aldoar | 98 | 98 | moderately hard |
| Campanhã | 98 | 98 | moderately hard |
| Matosinhos | 98 | 98 | moderately hard |
| São Mamede de Infesta | 98 | 98 | moderately hard |
| Senhora da Hora | 98 | 98 | moderately hard |
| Canidelo | 98 | 98 | moderately hard |
| Oliveira do Douro | 98 | 98 | moderately hard |
| Águas Santas | 97 | 97 | moderately hard |
| Maia | 97 | 97 | moderately hard |
| Gondomar | 83 | 83 | moderately hard |
| Penafiel | 55 | 55 | soft |
| Baião | 26 | 26 | soft |