Drilling a private well on Koh Phangan: the groundwater permit you legally need

Do you need a permit to drill a well on Koh Phangan? Yes — under the Groundwater Act B.E. 2520 (1977), any well drawing water from below the Department of Groundwater Resources' (DGR) working depth threshold needs a drilling license before drilling starts and a separate use license before the water is pumped, and this applies regardless of land ownership. Given the island's recurring dry-season mains rationing (see Water supply and shortage risk on Koh Phangan), a private well is one of the few genuine hedges a buyer has — but only if it's properly licensed, not just physically present.

What counts as "groundwater" requiring a permit

Section 3 of the Act defines groundwater as water below a depth the Minister prescribes, set at no less than 10 metres; DGR's current operating threshold — confirmed directly by its Region 6 office, which covers Surat Thani province (and therefore Koh Samui, Koh Phangan and Koh Tao) alongside Trang, Krabi, Phang Nga, Phuket, Chumphon, Ranong and Nakhon Si Thammarat — is 15 metres. In practice this catches almost every drilled well on the island: the granite-and-sandstone aquifers that give reasonable dry-season yield typically sit well past that mark.

Two separate licenses, not one

• Drilling license — required before any rig touches the ground (Sections 16–18). Valid for up to one year (Section 20(1)).
• Use license — required before the water is actually pumped and used. Valid for up to ten years, renewable before expiry (Section 20(2)).
• Both are issued by the local groundwater office — for Koh Phangan, DGR's Region 6 branch — and neither exemption depends on holding a chanote or any other title to the land itself.

Fees and typical cost

Under the Act's fee schedule, an application costs around ฿10 per document and each license roughly ฿1,000. Usage itself is fee-exempt for domestic and small-scale agricultural consumption up to 50 m³ a day; above that, or for commercial use, the standard rate runs around ฿8.50 per m³. None of this covers the physical drilling — a standard 4-inch well from a private contractor typically runs ฿40,000–120,000 in southern Thailand, on top of the license fees.

The penalty for skipping it

Section 16 makes unlicensed drilling, use or discharge into a well an offence, whatever the landowner's intentions: up to six months' imprisonment, a fine of up to ฿20,000, or both, with the court empowered to order the well filled in and equipment seized at the offender's expense. It is enforced, not a dead letter — provincial groundwater offices routinely inspect wells flagged by neighbours or during other permit applications.

What this means before you buy

• Ask for both licenses, in the current owner's name — not just proof a well exists. A drilled well with no paperwork is an inherited liability, not a free asset; fold it into due diligence before buying alongside title and zoning checks.
• A pump running on an unlicensed well can be shut down and the well ordered filled — don't rely on one as a dry-season backup without confirming both licenses are current.
• If a well needs drilling as part of a build, apply through a local groundwater-licensed contractor rather than an informal driller; the license itself is what makes the asset transferable and defensible later, alongside the building's own permit (see Building a villa on Koh Phangan).

None of this makes a well impractical — it's a routine, inexpensive permit most owners never think to ask about. Making “well licensed and current” a written condition in the sale or construction contract turns a common informal shortcut into a properly documented, defensible asset.