β¦ Back to Water Resource Management Home
ΒΆ Introduction
Contains survey statistics of laboratory results from water samples submitted to ServiTech Laboratories during 2011 to 2022, inclusive, for analysis of irrigation water suitability. The results are grouped by National Agricultural Statistics Service (USDA-NASS) reporting districts.
ΒΆ Figure 1. Idaho 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 |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 470 | 145 β 805 | 90 β 3510 |
| South Central | 225 | ---- | ---- |
| Southeast | 495 | 270 β 990 | ---- |
| Statewide | 425 | 175 β 805 | 90 β 2295 |
("Acceptable" = 2000 - 4000 TDS mg/L)
ΒΆ Table 2. Sulfate, SO4 mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 35 | 5 β 140 | 2 β 2600 |
| South Central | 25 | ---- | ---- |
| Southeast | 35 | 24 β 158 | ---- |
| Statewide | 35 | 7 β 110 | 2 β 1800 |
("Acceptable" = 200 - 500 SO4 mg/L)
ΒΆ Table 3. Nitrate-nitrogen, NO3-N mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 0.2 | 0.2 β 0.4 | 0.2 β 12.3 |
| South Central | 0.4 | ---- | ---- |
| Southeast | 1.6 | 0.2 β 14.2 | ---- |
| Statewide | 0.3 | 0.2 β 1.0 | 0.2 β 24.8 |
("Acceptable" = 30 - 70 NO3-N mg/L)
ΒΆ Table 4. Chloride, Cl mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 26 | 4 β 74 | 1 β 397 |
| South Central | 18 | ---- | ---- |
| Southeast | 45 | 8 β 178 | ---- |
| Statewide | 24 | 5 β 74 | 1 β 363 |
("Acceptable" = 125 - 250 Cl mg/L)
ΒΆ Table 5. Calcium, Ca mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 17 | 8 β 76 | 2 β 444 |
| South Central | 39 | ---- | ---- |
| Southeast | 64 | 9 β 166 | ---- |
| Statewide | 23 | 9 β 77 | 2 β 346 |
("Acceptable" = 80 - 120 Ca mg/L)
ΒΆ Table 6. Magnesium. Mg mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | |||
| South Central | |||
| Southeast | |||
| Statewide | |||
("Acceptable" = 50 - 120 Mg mg/L)
ΒΆ Table 7. Potassium, K mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 6 | 3 β 9 | 2 β 36 |
| South Central | 4 | ---- | ---- |
| Southeast | 5 | 2 β 10 | ---- |
| Statewide | 6 | 3 β 9 | 2 β 27 |
("Acceptable" = 80 - 120 K mg/L)
ΒΆ Table 8. Sodium, Na mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 83 | 19 β 200 | 8 β 1037 |
| South Central | 19 | ---- | ---- |
| Southeast | 58 | 8 β 128 | ---- |
| Statewide | 63 | 18 β 170 | 7 β 712 |
("Acceptable" = Na plus Mg less than 50% of TDS)
ΒΆ Table 9. Iron, Fe mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 0.10 | 0.06 β 0.47 | 0.05 β 3.44 |
| South Central | 0.18 | ---- | ---- |
| Southeast | 0.08 | 0.05 β 0.31 | ---- |
| Statewide | 0.10 | 0.05 β 0.33 | 0.05 β 2.11 |
("Acceptable" = 0.20 - 0.40 Fe mg/L)
ΒΆ Table 10. Manganese, Mn mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 0.029 | 0.008 β 0.074 | 0.005 β 13.560 |
| South Central | 0.208 | ---- | ---- |
| Southeast | 0.005 | 0.005 β 0.157 | ---- |
| Statewide | 0.017 | 0.005 β 0.074 | 0.005 β 8.680 |
("Acceptable" = 0.025 - 0.050 Mn mg/L)
ΒΆ Table 11. Hardness, as CaCO3 grains/gallon |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 3.9 | 1.3 β 17.0 | 0.6 β 78.0 |
| South Central | 8.5 | ---- | ---- |
| Southeast | 16.5 | 3.3 β 38.0 | ---- |
| Statewide | 5.3 | 2.3 β 21.0 | 0.6 β 62.4 |
("Moderately hard" = 3.5 - 7.0 CaCO 3 grains/gallon)
ΒΆ Table 12. Hardness, as CaCO3 mg/L |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 65 | 25 β 290 | 10 β 1300 |
| South Central | 150 | ---- | ---- |
| Southeast | 280 | 55 β 655 | ---- |
| Statewide | 90 | 40 β 350 | 10 β 1055 |
("Moderately hard" = 60 to 120 CaCO 3 mg/L)
ΒΆ Table 13. Electrical conductivity, EC ΞΌmho/cm |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 735 | 225 β 1260 | 140 β 5480 |
| South Central | 350 | ---- | ---- |
| Southeast | 775 | 420 β 1550 | ---- |
| Statewide | 660 | 275 β 1260 | 140 β 3585 |
("Acceptable" = 1300 - 2600 Β΅mho/cm)
ΒΆ Table 14. Water pH |
|||
| Idaho Districts | Median | Typical range | Low - High |
| Southwest | 8.0 | 7.6 β 8.3 | 5.8 β 8.9 |
| South Central | 7.9 | ---- | ---- |
| Southeast | 8.3 | 7.6 β 8.8 | ---- |
| Statewide | 8.1 | 7.6 β 8.3 | 6.3 β 9.2 |
("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 |
|
| Southwest | 23 |
| South Central | 2 |
| Southeast | 6 |
| Statewide | 31 |