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ΒΆ Introduction
Survey of analysis results from South Dakota surface and groundwater samples submitted to ServiTech Laboratories during 2013 to 2022, inclusive, for analysis of Livestock Suitability. The results are grouped by National Agricultural Statistics Service (USDA-NASS) reporting districts.
ΒΆ Figure 1. South Dakota USDA-NASS Districts
Interpretation of survey results:
- Median = 50th percentile
- Typical range = 25th and 75th percentiles
- Low - High = 5th and 95th percentiles
ΒΆ Table 1. Total dissolved solids, TDSc mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 1855 | 855 β 3605 | 165 β 7310 |
| North Central | 1500 | 800 β 2160 | 260 β 5035 |
| Northeast/Central | 1560 | 1115 β 1780 | 385 β 3330 |
| West Central | 2260 | 730 β 3820 | 155 β 10525 |
| East Central | 1220 | 645 β 1520 | 405 β 2215 |
| Southwest | 2110 | 1260 β 4565 | 90 β 20440 |
| South Central/Southeast | 1080 | 505 β 1640 | 190 β 4655 |
| Statewide | 1540 | 820 β 2640 | 205 β 6885 |
("Acceptable" = 2000 - 4000 TDS mg/L)
ΒΆ Table 2. Sulfate, SO4 mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 1100 | 258 β 2300 | 8 β 6245 |
| North Central | 720 | 150 β 1300 | 8 β 4050 |
| Northeast/Central | 1100 | 435 β 1300 | 26 β 2790 |
| West Central | 1450 | 245 β 2925 | 4 β 6900 |
| East Central | 680 | 120 β 1000 | 34 β 1500 |
| Southwest | 1700 | 410 β 4000 | 4 β 38600 |
| South Central/Southeast | 600 | 55 β 1100 | 3 β 4350 |
| Statewide | 930 | 230 β 1800 | 8 β 5900 |
("Acceptable" = 200 - 500 SO4 mg/L)
ΒΆ Table 3. Nitrate-nitrogen, NO3-N mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 0.2 | 0.2 β 0.2 | 0.2 β 10.0 |
| North Central | 0.2 | 0.2 β 0.2 | 0.2 β 12.3 |
| Northeast/Central | 0.2 | 0.2 β 0.2 | 0.2 β 2.6 |
| West Central | 0.2 | 0.2 β 0.2 | 0.2 β 20.4 |
| East Central | 0.2 | 0.2 β 0.8 | 0.2 β 20.1 |
| Southwest | 0.2 | 0.2 β 0.3 | 0.2 β 1039 |
| South Central/Southeast | 0.4 | 0.2 β 3.8 | 0.2 β 40.7 |
| Statewide | 0.2 | 0.2 β 0.2 | 0.2 β 12.7 |
("Acceptable" = 30 - 70 NO3-N mg/L)
ΒΆ Table 4. Calcium, Ca mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 75 | 25 β 176 | 5 β 440 |
| North Central | 108 | 56 β 270 | 11 β 495 |
| Northeast/Central | 240 | 71 β 379 | 10 β 516 |
| West Central | 91 | 35 β 204 | 8 β 403 |
| East Central | 156 | 64 β 300 | 6 β 444 |
| Southwest | 289 | 62 β 440 | 1 β 765 |
| South Central/Southeast | 125 | 72 β 255 | 28 β 400 |
| Statewide | 110 | 42 β 260 | 7 β 458 |
("Acceptable" = 80 - 120 Ca mg/L)
ΒΆ Table 5. Magnesium, Mg mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 64 | 8 β 220 | 1 β 788 |
| North Central | 64 | 26 β 113 | 4 β 578 |
| Northeast/Central | 75 | 30 β 98 | 3 β 229 |
| West Central | 48 | 10 β 183 | 1 β 460 |
| East Central | 47 | 22 β 87 | 2 β 170 |
| Southwest | 112 | 14 β 532 | 1 β 6272 |
| South Central/Southeast | 41 | 24 β 80 | 6 β 418 |
| Statewide | 63 | 17 β 160 | 2 β 684 |
("Acceptable" = 50 - 120 Mg mg/L)
ΒΆ Table 6. Potassium, K mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 14 | 6 β 30 | 2 β 66 |
| North Central | 28 | 14 β 60 | 5 β 150 |
| Northeast/Central | 22 | 19 β 30 | 7 β 79 |
| West Central | 18 | 11 β 27 | 4 β 51 |
| East Central | 11 | 7 β 16 | 2 β 23 |
| Southwest | 19 | 8 β 34 | 3 β 115 |
| South Central/Southeast | 17 | 7 β 22 | 1 β 41 |
| Statewide | 18 | 9 β 30 | 3 β 87 |
("Acceptable" = 80 - 120 K mg/L)
ΒΆ Table 7. Sodium, Na mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 428 | 109 β 809 | 12 β 1700 |
| North Central | 187 | 71 β 524 | 11 β 1350 |
| Northeast/Central | 132 | 68 β 342 | 15 β 828 |
| West Central | 541 | 162 β 1118 | 13 β 2808 |
| East Central | 110 | 36 β 222 | 12 β 744 |
| Southwest | 542 | 152 β 1270 | 4 β 7090 |
| South Central/Southeast | 100 | 40 β 251 | 5 β 1250 |
| Statewide | 255 | 74 β 645 | 12 β 1712 |
("Acceptable" = Na plus Mg less than 50% of TDS)
ΒΆ Table 8. Chloride, Cl mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 22 | 10 β 45 | 3 β 195 |
| North Central | 65 | 38 β 174 | 10 β 823 |
| Northeast/Central | 82 | 35 β 159 | 10 β 442 |
| West Central | 35 | 18 β 86 | 6 β 268 |
| East Central | 25 | 7 β 97 | 2 β 311 |
| Southwest | 30 | 13 β 121 | 2 β 466 |
| South Central/Southeast | 35 | 11 β 108 | 2 β 287 |
| Statewide | 37 | 15 β 92 | 4 β 341 |
("Acceptable" = 125 - 250 Cl mg/L)
ΒΆ Table 9. Electrical conductivity, EC ΞΌmho/cm |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 2880 | 1310 β 4530 | 245 β 8575 |
| North Central | 2350 | 1250 β 3370 | 410 β 7870 |
| Northeast/Central | 2440 | 1745 β 2780 | 600 β 5205 |
| West Central | 3530 | 1140 β 5455 | 245 β 11200 |
| East Central | 1900 | 1010 β 2380 | 630 β 3465 |
| Southwest | 3300 | 1965 β 7135 | 145 β 31980 |
| South Central/Southeast | 1680 | 785 β 2560 | 300 β 7270 |
| Statewide | 2410 | 1280 β 3890 | 315 β 8425 |
("Acceptable" = 1300 - 2600 ΞΌmho/cm)
ΒΆ Table 10. Iron, Fe mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 0.32 | 0.14 β 0.93 | 0.05 β 10.3 |
| North Central | 0.47 | 0.17 β 1.30 | 0.05 β 7.1 |
| Northeast/Central | 0.48 | 0.24 β 1.28 | 0.05 β 2.7 |
| West Central | 0.41 | 0.19 β 1.43 | 0.05 β 5.9 |
| East Central | 0.33 | 0.05 β 1.58 | 0.05 β 4.6 |
| Southwest | 0.36 | 0.14 β 1.55 | 0.05 β 5.4 |
| South Central/Southeast | 0.37 | 0.12 β 1.20 | 0.05 β 4.0 |
| Statewide | 0.37 | 0.15 β 1.22 | 0.05 β 6.3 |
("Acceptable" = 0.20 - 0.40 Fe mg/L)
ΒΆ Table 11. Manganese, Mn mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 0.078 | 0.018 β 0.265 | 0.005 β 1.00 |
| North Central | 0.323 | 0.080 β 1.575 | 0.013 β 4.78 |
| Northeast/Central | 0.150 | 0.078 β 0.762 | 0.016 β 2.70 |
| West Central | 0.193 | 0.047 β 0.595 | 0.007 β 1.45 |
| East Central | 0.137 | 0.019 β 0.404 | 0.005 β 1.65 |
| Southwest | 0.059 | 0.018 β 0.488 | 0.005 β 24.14 |
| South Central/Southeast | 0.100 | 0.020 β 0.255 | 0.005 β 2.50 |
| Statewide | 0.140 | 0.031 β 0.500 | 0.005 β 2.40 |
("Acceptable" = 0.025 - 0.050 Mn mg/L)
ΒΆ Table 12. Hardness, as CaCO3 grains/gallon |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 33 | 6.3 β 80 | 1.0 β 249 |
| North Central | 33 | 15.0 β 76 | 2.4 β 200 |
| Northeast/Central | 56 | 18.3 β 78 | 2.2 β 110 |
| West Central | 27 | 7.7 β 84 | 1.4 β 140 |
| East Central | 35 | 15.0 β 67 | 1.3 β 104 |
| Southwest | 71 | 12.0 β 195 | 0.6 β 1550 |
| South Central/Southeast | 32 | 16.0 β 66 | 5.9 β 150 |
| Statewide | 36 | 11.0 β 77 | 1.6 β 210 |
("Moderately hard" = 3.5 - 7.0 CaCO3 grains/gallon)
ΒΆ Table 13. Hardness, as CaCO3 mg/L |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 550 | 110 β 1325 | 15 β 4290 |
| North Central | 560 | 250 β 1300 | 40 β 3400 |
| Northeast/Central | 960 | 315 β 1300 | 35 β 1895 |
| West Central | 465 | 130 β 1425 | 25 β 2400 |
| East Central | 600 | 250 β 1100 | 25 β 1740 |
| Southwest | 1200 | 210 β 3300 | 10 β 26700 |
| South Central/Southeast | 540 | 270 β 1150 | 105 β 2600 |
| Statewide | 620 | 190 β 1300 | 25 β 3600 |
("Moderately hard" = 60 to 120 CaCO3 mg/L)
ΒΆ Table 14. Water pH |
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| South Dakota Districts | Median | Typical range | Low - High |
| Northwest | 8.2 | 7.9 β 8.6 | 6.9 β 9.3 |
| North Central | 7.9 | 7.6 β 8.2 | 7.2 β 8.9 |
| Northeast/Central | 7.8 | 7.5 β 8.0 | 7.2 β 8.6 |
| West Central | 8.2 | 7.8 β 8.5 | 7.4 β 9.5 |
| East Central | 7.8 | 7.6 β 8.0 | 7.3 β 8.4 |
| Southwest | 7.9 | 7.7 β 8.5 | 7.1 β 8.9 |
| South Central/Southeast | 7.8 | 7.6 β 8.1 | 7.2 β 8.7 |
| Statewide | 8.0 | 7.7 β 8.4 | 7.2 β 9.1 |
("Neutral" pH = 6.5 - 7.5)
ΒΆ Table 15. Conversion Factors |
| 1 mg/L β 1 ppm |
| 1 mg/L = 1,000 Β΅g/L |
| 1 mmho/cm = 1 dS/m |
| 1 mmho/cm = 1,000 Β΅mho/cm lb/ac-in = mg/L x 0.2267 lb/ac-ft = mg/L x 2.7204 |
| lime equivalent, lb/ac-ft = HCO3 mg/L x 2.2304 |
| 1 acre-inch = 27,154 gallons |
| 1 acre-foot = 325,848 gallons |
ΒΆ Table 16. Sample Count |
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| Northwest | 350 |
| North Central | 194 |
| Northeast | 13 |
| West Central | 94 |
| Central | 107 |
| East Central | 71 |
| Southwest | 53 |
| South Central | 17 |
| Southeast | 52 |
| Statewide | 951 |