WATER QUALITY - Hardness of water

                                        March 22, 1962

QUALITY OF WATER BRANCH MEMORANDUM NO. 62.47

To:      District Chiefs and Staff Officials, Water Resources
         Division

From:    Chief, Quality of Water Branch

Subject: WATER QUALITY - Hardness of water

We have had no uniform policy in classifying water hardness 
by numerical ranges or adjective ratings.  This subject again 
came up in connection with manuscript preparation for reports 
on public water supplies of the United States.  Country-wide, 
there is need for standardization.

After discussion with field and Washington staff members, I 
am establishing the following breakdown, which will 
henceforth be used where hardness classification is 
discussed:

          Hardness range           Adjective rating
               (ppm)
               0-60                     soft
              61-120                    moderately hard
             121-180                    hard
             181 +                      very hard

Because hardness grouping is of interest to many offices of 
the Division, copies of this memorandum are being mailed to 
all field installations.


                                   S. K. Love

WRD Dist:  A, B, S, FO.