Drinking Water Well Condition: Assessing Drinking Water Contamination Risk

For each category listed on the left that is appropriate to your situation, click the box under rank 1-4 that best applies. Your "rank number" will then be genrated on the right.

Glossary for this Fact Worksheet

Information for this Fact Worksheet (PDF)

 

Please Select Your County:

Well Location (Addressed in Section 1)
 
Low Risk
(rank 4)
Low-Mod Risk
(rank 3)
Mod-High Risk
(rank 2)
High Risk
(rank 1)
Your Rank
1. Position of drinking water well in relation to contamination sources Up slope from all potential sources of contamination.
No surface water runoff reaches well. Surface water diverted from well. 		Up slope from or at grade with potential sources of contamination. No surface water runoff reaches well. Down slope from most potential sources of contamination. Some surface water runoff may reach the well. Settling or depression near casing. Surface water runoff reaches the well.

 

 
2. Separation
distances between well and homestead contamination sources*		 All potential sources of contamination are greater than the recommended separation distances from the well. Most potential sources of contamination meet the recommended minimum separation distances from the well. Some potential sources of contamination meet the recommended minimum separation distances from the well. None of the potential sources of contamination meet the recommended minimum separation distances from the well.

 

 
3. Soil (< 5' below ground surface) potential to protect ground water Fine-textured soils
(clay loams, silty clay).		 Medium-textured soils (silt loam, loam). Medium textured soils. Coarse-textured soils (sands, sandy loam).

 

 
4. Geology (> 5' below ground surface) potential to protect ground water --- Clay layers present above the water bearing zones. Clay layers absent above the water bearing zones. Fractured consolidated
formations such as basalts

   

 
*See page Fact/Worksheet 1, page 4, Drinking Water Well Condition, Separation Distances.

Well Construction* (Addressed in Section 2)
5. Condition of casing, well cap, and pitless adapter No holes or cracks in casing. An approved sanitary well cap tightly secured. Screened vent. Pitless adapter in place. No defects visible.
Approved sanitary seal tightly secured. Well vented but not screened.		 No holes or cracks visible. Cap loose. Cap missing or loose. No pitless adapter. Holes or cracks visible. Can hear water draining.

 

 
6. Casing depth
and surface seal		 Casing extends below water level in well and is more than 18 feet below surface. At least 18 feet of surface seal is in place, or into the confining layer above the aquifer in which the well is completed.** Casing extends to water level, but not less than 18 feet below surface.
Required 18-foot surface seal is in place.**		 Surface seal missing
or less than required depth.**		 No surface seal.**

 

 
7. Casing height above land surface More than 12 inches above grade. No flood water reaches well. 12 inches above grade. Possibility of flood water reaching well. Less than 12 inches above grade. Possibility of flood water reaching well. Below grade or in pit or basement. Likely to be flooded.

 

 
8. Well age Constructed following Idaho well guidelines,
enacted 1987.		 --- Constructed and seal is placed before 1987. Not constructed according to Idaho regulations.

 

 

 

Well Management (Addressed in Sections 3, 4, and 5)
9. Backflow prevention Anti-backflow devices (such as check valves) installed on all faucets with hose connections. No cross-connections between water supplies. Anti-backflow devices installed on some faucets with hose connections. No anti-backflow devices. Air gap maintained. No anti-backflow devices. Air gap not maintained. Cross-connections between water supplies.

 

 
10. Water testing Regular annual testing. Records indicate
consistent, satisfactory water quality. Bacteria, nitrate, and other tests meet standards.		 Regular testing. Records indicate increased levels of bacteria, nitrate, or other contaminants, but still meet standards. Regular testing. Bacteria, nitrate, and other tests do not meet standards some of the time but are closely monitored. No water tests done or tests indicate bacteria, nitrate, or other
contaminant levels
frequently above
standards. Noticeable changes in color, clarity, odor, or taste after
rainstorms or during spring melt.

 

 
11. Unused wells No unused, unsealed wells. Unused wells properly
abandoned and protected according to Idaho specifications.		 Unused wells, more than 100 feet from drinking water well, not properly abandoned. Unused well, less than 100 feet from drinking water well, not properly
abandoned.

 

 
Boldface type: Besides representing a higher-risk choice, this practice also violates Idaho law.
*See page 2 of the Drinking Water Well Condition Fact/Worksheet for well construction requirements in Idaho.
**An 18 foot surface seal is required for all new well installations. Existing wells must meet requirements in effect at time of construction. Placement of a surface seal in all wells is required.