Published
Some ground is harder to drill in, and Idaho marks it on a map
Some ground gets a warning label
Most of Idaho drills by one set of rules. Some ground — where the water is under pressure, warm, or already compromised — carries a designation that tightens everything at once:
“The Director may designate an ‘area of drilling concern’ to protect public health, or to prevent waste and contamination of ground or surface water, or both, because of factors such as aquifer pressure, vertical depth to the aquifer, warm or hot ground water, or contaminated ground or surface waters.”
— IDAPA 37.03.09 §040.01.a, areas of drilling concern (effective 3-18-22). Retrieved 28 September 2026
Four factors do the triggering: aquifer pressure, vertical depth to the aquifer, warm or hot ground water, and contaminated ground or surface waters. The designation exists to protect public health or prevent waste and contamination — or both at once. It is the state saying: on this ground, an ordinary well is not an ordinary well.
One more layer, never a replacement
The designation does not supersede or preclude the heavier ones (3-18-22): a Critical Ground Water Area (Section 42-233a, Idaho Code), a Ground Water Management Area (Section 42-233b), or a Geothermal Resource Area (Sections 42-4002 and 42-4003) can sit on the same ground. And the line is drawn aquifer by aquifer, not square mile by square mile: a designation can include certain aquifers or portions while excluding others — low temperature geothermal resources in, the shallower cold ground water systems out. Two wells on one parcel can face different rules.
What tightens inside the line
- The driller’s bond. A minimum of $10,000 filed with the Director for the construction or modification of any well in the area — unless it can be shown to the Director’s satisfaction that a smaller bond is sufficient (3-18-22). And the Director may require a larger bond case by case, based on the estimated cost to repair, complete or properly decommission the well (7-1-25).
- The driller’s record. Demonstrated to the Director’s satisfaction: the experience and knowledge to construct or decommission a well that encounters warm water or pressurized aquifers (7-1-25).
- The equipment. The driller must have, or have immediate access to, the specialized equipment or resources the work needs (7-1-25).
- The fast lane. Start cards and verbal approvals are not allowed for wells constructed in a designated area of drilling concern — nor in a Critical Ground Water Area, Ground Water Management Area or Area of Contamination — unless the Director otherwise authorizes. The permit routes are explained here.
How to check your ground
The state puts the boundaries on a public map, and this page will not tell you what is designated — designations are aquifer-specific and move with the science. The check takes minutes:
“Use the map below to view well locations layered with areas of drilling concern in addition to nitrate priority areas, groundwater management areas, and more.”
— Idaho Department of Water Resources, Find a Well map, idwr.idaho.gov/wells/find-a-well-map/. Retrieved 28 September 2026
Open idwr.idaho.gov/wells/find-a-well-map/, find the parcel, and read the layers stacked on it — the same map shows the nitrate priority areas that drive the septic-side analysis. A boundary touching a neighbor’s ground is not a rumor; it is a fact you can see before paying for a single foot of drilling.
Before you budget a well in uncertain ground
- Check the parcel on the Find a Well map — areas of drilling concern, nitrate priority areas, groundwater management areas, all layered.
- Ask the licensed driller what the designation demands: the bond, the record, the equipment.
- Plan on the full issued permit — no start card, no verbal approval inside the line.
- If the ground runs warm as well as tight, read what the low-temperature geothermal rules add.
- Confirm everything with the department before the rig commits — then bring the map printout and the well plan to (208) 656-1467.
Common questions
What is an area of drilling concern?
An area the Director of the Idaho Department of Water Resources may designate to protect public health or prevent waste and contamination of ground or surface water, because of factors such as aquifer pressure, vertical depth to the aquifer, warm or hot ground water, or contaminated waters.
Does the designation replace other groundwater designations?
No. An area of drilling concern does not supersede or preclude designation of the same ground as a Critical Ground Water Area, Ground Water Management Area, or Geothermal Resource Area - those statutes stack.
Can part of an aquifer be inside and part outside?
Yes. The designation can include certain aquifers or portions thereof while excluding others - for example, low temperature geothermal resources in while the shallower cold ground water systems stay out.
What bond does a driller need inside an area of drilling concern?
A minimum of $10,000 filed with the Director for construction or modification of any well, unless a smaller bond is shown sufficient to the Director's satisfaction. The Director may also require more, case by case, based on the estimated cost to repair, complete or properly decommission a well.
What extra must a driller demonstrate inside one?
Two things, to the Director's satisfaction: the experience and knowledge to adequately construct or decommission a well encountering warm water or pressurized aquifers, and possession of - or immediate access to - the specialized equipment or resources the work needs.
Can you use a start card or verbal approval in an area of drilling concern?
No. Verbal approval and start card permits are not allowed for wells constructed in a designated Area of Drilling Concern, Critical Ground Water Area, Ground Water Management Area or Area of Contamination, unless the Director otherwise authorizes.
How do I find out whether my property is in one?
Check IDWR's Find a Well map at idwr.idaho.gov/wells/find-a-well-map/ - it layers well locations with areas of drilling concern, nitrate priority areas and groundwater management areas - then confirm with the department before budgeting the well.
Is Island Park in an area of drilling concern?
This page will not assert either way: designations are aquifer-specific and change over time. The reliable answer is the state's map checked against your parcel, and the department's confirmation - not a brochure's memory.
Why does the designation exist at all?
Because some ground punishes ordinary drilling - pressure, heat and contamination turn a routine well into a hazard. The designation lines up the bond, the driller's demonstrated experience, and the permit route with the actual risk.