Drinking Water Well Condition: Assessing Drinking Water Contamination Risk
| Low Risk | Low - Moderate Risk | Moderate - High Risk | High - Risk | |
| Fertilizer Storage | ||||
Dry Formulation:
| None stored at any time. Covered on Impermeable surface (such as concrete or asphalt). Spills are collected. | Less then 1 ton. Covered on clay soil. Spills are collected | Between 1 and 20 tons. Partially covered on loamy soils. Spills not collected. | More then 20 tons. Not covered on sandy soils. Spills not collected. |
Liquid formulation:
| None stored at any time Concrete or other impermeable secondary contain - ment does not allow spill to con - taminate soil. | Less then 55 gallons Clay lined secondary contain - ment. Most of spill can be recovered. | Between 55 and 1500 gallons. Somewhat permeable soils (loam). No secondary contain - ment. Most of spill cannot be recovered. | More then 1500 gallons. Permeable soil (sand). No secondary contain - ment. Spills con - taminate soil.. |
| Containers | Original containers clearly labeled. No holes tears or weak seams. Lids tight. | Original containers old. Labels partially missing or hard to read. | Containers old but patched. Metal containers showing signs of rusting. | Containers have holes or tears that allow fertilizers to leak. No labels. |
| Security. | Fenced or locked area separate from all other activities , or locks on valves | Fenced area separate from most other activities. | Open to activities that could damage containers or spill fertilizer. | Open access to theft, vandalism and children. |
| Mixing and Loading Practices | ||||
| Location of well in relation to mixing - loading area with no curbed and impermeable contain - ment area. | 100 feet or more downslope from well. | 50 to 100 feet downslope from well. | 10 to 50 feet downslope or 100 to 500 feet upslope from well. | Within 10 feet downslope or less than 100 feet upslope from well. |
| Additional Mixing and Loading Practices for liquid Fertilizer | ||||
| Mixing and loading pad (spill contain - ment). | Concrete pad with curb keeps spills contained. Sump allows collection and transfer to storage. | Concrete pad with curb keeps spills contained. No sump. | Concrete pad with some cracks keeps some spills contained. No curb or sump. | No mixing - loading pad. Spills soak into ground. |
| Water source. | Separate water tank. | Hydrant away from well. | Hydrant near well. | Obtained directly from well. |
| Backflow prevention on water supply. | Anti - backflow device installed or 6 inch air gap maintained between hose and sprayer tank. | Anti - backflow device installed . hose in tank above waterline. | No anti - backflow device. Hose in tank above waterline. | No anti - flow device. Hose in tank below waterline. |
| Filling supervision. | Constant. | Mostly constant. | Frequent. | Seldom or never. |
| Handling system. | Closed system for all liquid product transfers | closed system for most liquids. Some liquids hand poured. Sprayer fill port easy to reach. | All liquids hand poured. Sprayer fill port easy to reach. | All liquids hand poured. Sprayer fill port hard to reach. |
| Clean-up and Disposal Practices | ||||
| Sprayer cleaning and rinsate (rinse water) disposal. | Sprayer washed out an field. Rinsate used in next load and applied to crop. | Sprayer washed out on pad. Rinsate used in next load and applied to crop. | Sprayer washed out at homestead. Rinsate applied on nearby field. | Sprayer washed out at homestead. Rinsate sprayed less than 100 feet from well. |
December 8, 1997
Dr. Dennis Hoffman, Project Leader
Steve Dagitz, Webmaster
