The table below shows conversions between water conductivity and resistivity. It also converts resistivity to conductivity, and to parts per million or milligrams per liter (ppm, mg/L).

Water Quality Conductivity Conversion Table

mg/L
Sodium
Chloride		 Total Dissolved
Solids as
mg/L CaCO3		 Specific
Conductance
(Microsiemens/cm)		 Specific
Resistance
Megaohm Ω		 Grains
per Gallon
Sodium Chloride
0.05 0.043 0.105 9.5238 0.0029
0.1 0.085 0.212 4.71698 0.0060
0.2 0.170 0.424 3.55849 0.012
0.3 0.255 0.637 1.56985 0.018
0.4 0.340 0.848 1.17924 0.023
0.5 0.425 1.06 0.943396 0.029
0.6 0.510 1.273 0.785545 0.035
0.7 0.595 1.985 0.6734 0.041
0.8 0.680 1.696 0.589622 0.047
0.9 0.765 1.908 0.524109 0.053
1 0.85 2.12 0.471698 0.06
2 1.70 4.24 0.235849 0.12
3 2.55 6.37 0.156985 0.18
4 3.40 8.48 0.117924 0.23
5 4.25 10.6 0.094339 0.29
6 5.10 12.73 0.078554 0.35
7 5.95 14.85 0.06734 0.41
8 6.80 16.96 0.058962 0.47
9 7.65 19.08 0.05241 0.53
10 8.5 21.2 0.047169 0.58
20 17.0 42.4 0.023584 1.17
30 25.5 63.7 0.015698 1.75
40 34.0 84.8 0.011792 2.34
50 42.5 106.0 0.009433 2.92
60 51.0 127.3 0.007855 3.51
70 59.5 148.5 0.006734 4.09
80 68.0 169.6 0.005896 4.68
90 76.5 190.8 0.005241
100 85 212 0.004716 5.85
200 170 410 0.002439 11.70
300 255 610 0.001639 17.5
400 340 812 0.001231 23.4
500 425 1,008 0.000992 29.2
600 510 1,206 0.000829 35.1
700 595 1,410 0.000709 40.9
800 680 1,605 0.000623 46.8
900 765 1,806 0.000553 52.6
1,000 850 2,000 0.0005 58.5
2,000 1700 3,830 0.000261 117
3,000 2550 5,760 0.000176 175
4,000 3400 7,500 0.000133 234
5,000 4250 9,240 0.000108 292
6,000 5100 10,950 0.000091 351
7,000 5950 12,650 0.000079 409
8,000 6800 14,340 0.000069 468
9,000 7650 16,000 0.000062 526
10,000 8500 17,600 0.000056 585