TOTAL HARDNESS

The measurements shown below were made at USGS station 01209710, located on the Norwalk River near the Perry Avenue bridge. All of the measurements are in milligrams per liter, as CaCO3. For details about the data, press here.

The highest reading, 110, occurred in 1/81, and the lowest, 43, in 4/84. All of the readings above 110 (9 percent of the samples), are shown in red and all that are below 62 (another 9 percent), are in blue.

 Averages by
Season and by
5-year Period:
 
(Overall = 84.6)
Jan-Mar81.1
Apr-Jun 80.7
Jul-Sep 87.7
Oct-Dec 88.1
1980-84 85.0
1985-89 85.0
1990-94 94.3
1995-99 82.3

YearJanFebMar AprMayJunJulAug SepOctNovDec
1980                   100    
1981 110     77     88     100    
1982 82     78     96       110  
1983 50                      
1984       43                
1985         84   85 85 86 93 70 83
1986 93   84 80 90 90 88 94 88      
1987                        
1988                        
1989                        
1990                        
1991                        
1992                        
1993                        
1994                   110 110 70
1995 63 88 73 95 97 81 91
81		 100 56 94    
1996 100 84   73   86 100 110 81 62   55
1997   65   64 73 100 71 84 93