Research · updated 2026-08-23 · download the county-level CSV
New Hampshire Well Depth & Drilling Cost Index
Drilling a private water well in New Hampshire means paying by the foot — so the two questions every well owner asks are how deep and how much. We computed both for all 10 counties with enough records to be reliable, from 106,477 official NHDES well records.
Statewide, the median well reaches 340 ft, and a complete system — drilling, casing, pump, pressure tank, and hookup — typically runs $24,300–$40,500. But the county spread is large:
Deepest counties to drill in New Hampshire
| County | Median depth | Typical depth range | Complete system |
|---|---|---|---|
| Carroll | 400 ft | 220 ft–550 ft | $26,400–$44,000 |
| Hillsborough | 385 ft | 250 ft–505 ft | $29,580–$49,300 |
| Sullivan | 360 ft | 225 ft–500 ft | $25,200–$42,000 |
| Merrimack | 345 ft | 240 ft–500 ft | $25,200–$42,000 |
| Grafton | 343 ft | 240 ft–500 ft | $24,360–$40,600 |
Most expensive counties to drill in New Hampshire
| County | Complete system | Drilling & casing only | Median depth |
|---|---|---|---|
| Hillsborough | $29,580–$49,300 | $12,325–$32,045 | 385 ft |
| Carroll | $26,400–$44,000 | $11,000–$28,600 | 400 ft |
| Merrimack | $25,200–$42,000 | $10,500–$27,300 | 345 ft |
| Sullivan | $25,200–$42,000 | $10,500–$27,300 | 360 ft |
| Grafton | $24,360–$40,600 | $10,150–$26,390 | 343 ft |
Download the full county table (CSV)
How to read this
- Depth is measured; cost is modeled. Depths are the median of recorded drilled depths per county. Cost applies published New Hampshire per-foot drilling rates to that local median depth — a planning estimate, not a quote. Actual bids vary with geology, casing, site access, and water depth.
- Counties below 30 records are excluded so a thin sample can't produce a misleading superlative.
- Records are drilling events from the state database, which include some replacement and abandoned wells; deeper counties reflect real local geology (bedrock, aquifer depth).
Sources & methodology
- New Hampshire well records: NHDES (refreshed weekly; see our general methodology).
- Percentiles (p25/median/p75) computed per county; cost from published per-foot rate ranges applied to the local median depth.
The county table is free to use with attribution to New Hampshire Well Data (newhampshirewelldata.com). For a specific county, a custom cut, or the underlying records, email — usually same-day.
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