Ask three drilling crews how deep a Samui well goes and you'll get three confident answers, all different. The truthful version: most wells we drill on the island land between 40 and 120 meters, and the spread inside that range is decided by geology that changes street to street.
Why the range is so wide
Samui is a granite island wearing a coat of weathered rock and sediment. Water moves through the fractured and weathered zones, and how deep those sit varies sharply with elevation and position. A plot near the ring road in Maenam and a hillside plot ten minutes up the same road are different drilling projects.
Depth also isn't the goal in itself — a stable yield is. A 60 m well producing steadily beats a 100 m well that was drilled deep to compensate for a poorly chosen spot.
What actually determines your depth
- Elevation and position — how far the water table sits below your ground level
- The fracture zones — where water actually moves in the granite
- Season of drilling — the survey accounts for dry-season water table drop
- Your demand — a household well and a resort well may stop at different layers
How to get a real number for your site
A site survey. It reads the terrain, nearby well data and access, and gives you an expected depth range and a fixed written quote before a rig ever arrives. Ours is free, and the number in the quote is the number you pay.