The water hardness in Onsdorf (54456) is approx. 13 °dH and is therefore medium in the hardness range.
This value was calculated from the neighbour cities.
The average water hardness in Rheinland-Pfalz is 15 °dH.
The water hardness directory is a community that allows each user to enter values for each city in the directory. Nothing but a user account is needed. The system controls itself practically, since each one can convey a value and from all values the average degree of hardness is determined. Nevertheless, all information is given without guarantee and should be checked in case of doubt.