Convert between °dH, mg/L and ppm as CaCO₃.Water hardness converter
Water hardness converter lets you compare results from different sources when hardness is reported in different units (°dH, ppm, mg/L as CaCO3). This is useful for sizing a softener, assessing scale risk and verifying performance after service.
Classification is approximate. Scale formation also depends on temperature, heating time and overall water chemistry. For sizing, rely on a measurement taken at the point of use.
FAQ - Water hardness converter
What is °dH?
German degrees (°dH) are a common hardness unit. 1 °dH equals 17.848 mg/L as CaCO3.
What does ppm mean for hardness?
Most often ppm is the same as mg/L as CaCO3. Always confirm the definition used by your tester or report.
How do I convert °dH to mg/L as CaCO3?
Multiply °dH by 17.848. This is the standard conversion.
What hardness is considered high?
In many homes, above roughly 14 °dH scale becomes a frequent issue. Thresholds vary by system and temperature.
How can I measure hardness at home?
Drop titration tests are the most accurate. Strip tests are fast but usually less precise.
Is water hardness constant in municipal supply?
Not always. It can change seasonally or after network work. Periodic checks are recommended.
Why does hard water create scale?
Higher calcium and magnesium levels precipitate during heating, creating deposits that affect appliances and fixtures.