The short answer: a well deeper than fifteen metres needs a licence, and you need two of them
Drilling on your own land, using the water yourself, paying for the rig yourself, still needs permission.
Groundwater is not something that comes with the land. It sits in a formation that runs under dozens of plots, so pumping it always affects somebody else. That is why the law is involved at all.
The most common misunderstanding is that this applies to factories, golf courses and large farms rather than to one house.
It applies to houses too.
And there are two separate licences: one to drill, another to use. Plenty of people obtain the first and stop there, assuming the job ends when the rig leaves, when the second is the one that makes every day's water lawful.
This article works through it in layers: the fifteen metre line that decides everything, the actual application, the three layers of cost, the ongoing duties people forget, and then the part that matters more than any licence, which is whether the water is fit to drink and how you would know.
The fifteen metre line decides which law you are under
The Groundwater Act B.E. 2520 defines groundwater as water below the surface deeper than the depth fixed by ministerial regulation, and that depth is fifteen metres.
The line splits the world cleanly.
Shallower than fifteen metres, such as the concrete ring wells dug traditionally, is not groundwater under this Act and needs no drilling licence.
Deeper than fifteen metres is groundwater in full, and both drilling and use need permission.
The catch is that in most of the country, a well yielding enough water all year round is almost never shallower than fifteen metres.
Household boreholes usually go down tens of metres, sometimes over a hundred, because shallower layers do not yield enough, dry out in the hot season, or are too easily contaminated from the surface.
So in practice, if you are seriously considering a borehole, assume from the outset that you need a licence and be pleasantly surprised if the well turns out shallow enough.
One more caution: the depth the driller quotes and the depth actually reached are not always the same. Some drillers sidestep the licensing question by telling the owner it is only a dozen metres or so while the rig goes far deeper. The person who carries the legal consequence is the landowner, not the driller.
Put the real depth in the quotation and the completion note, and keep the well log. Not to fight a case with, but because the day the well misbehaves, that paperwork is the only thing that tells you how deep the casing goes and where the screen sits.
Two licences, doing two different jobs
This is where people get lost, because it sounds like one thing while the law treats it as two acts.
The drilling licence permits putting a rig in the ground and opening the well. The application is form Nor Bor 1.
The use licence permits pumping water out of that well. The application is form Nor Bor 2.
They are separate because they affect different things.
Drilling affects the formation, and done badly it opens a path for poor quality water to run down into a good aquifer, which is damage that is close to impossible to reverse.
Use affects how much water the aquifer holds and how the ground behaves above it, which is why it is controlled through metering and charges.
In practice, somebody holding only the drilling licence and using the water anyway is using groundwater without permission, which is a separate offence from drilling.
Where to apply. To the local groundwater officer, which sits in different offices depending on the area.
- In Bangkok, the Bureau of Groundwater Operations Control at the Department of Groundwater Resources.
- In provinces where the function has been transferred to local administration, such as Khon Kaen, Chiang Mai and Nakhon Ratchasima, at the local administrative organisation.
- Elsewhere, at the Provincial Office of Natural Resources and Environment.
Telephone the office first. The transfer of this function to local administrations keeps widening, and nothing is more wasteful than driving to the wrong counter.
The application fee is 10 baht per form, which surprises most people by being far smaller than expected.
The licence fee goes by bore size:
- Small bores of 2 to 3 inches, including ring wells, 100 baht each.
- Medium bores of 4 to 6 inches, 500 baht each.
- Large bores of 8 inches and above, 1,000 baht each.
An ordinary house is usually in the small to medium band, so this is a matter of hundreds of baht.
Once lodged, officials have fifteen days to check the documents are complete. Anything missing is requested, and a complete file goes to the authorised officer for a decision.
That fifteen days is document checking, not the time until a licence issues, which is why getting the file right on the first pass saves more time than anything else.
The documents
The set every office asks for:
- Identity card and house registration of the applicant, with copies.
- Title to the land, a chanote or Nor Sor 3 Kor, showing you have the right to drill there.
- Written consent from the landowner if the land is not yours, for instance a rented plot or land still in a parent's name.
- A sketch map showing the intended location and the access route.
- A power of attorney if the drilling company lodges on your behalf.
- Company registration documents if the applicant is a company.
The third item trips people up most. A house built on a parent's or relative's land means the applicant and the landowner are different people, and that needs consent in writing, not an assurance that it is your mother's land.
The real cost has three layers, and the largest is not the fees
Anybody budgeting from the government fees alone is in for a surprise when the quotations arrive.
Layer one, the official fees. Ten baht per application, a few hundred for the licence depending on bore size. Not much money.
Layer two, the drilling itself. This is the large one. It depends on depth, bore size, the formation being drilled, and how far the rig has to be hauled in. Drilling through clay and drilling through hard rock are very different prices.
It also covers casing, screen, well development afterwards, the submersible pump, cable, control box, and the pipework into the house.
Prices vary so much by area and depth that no average figure quoted anywhere is worth trusting. Get three quotations from firms actually working in your area and compare what each one includes.
The cheapest usually leaves out the pump and the pipework, two items large enough to reverse the whole ranking.
Layer three, the monthly water charge. A use licence holder is liable for the groundwater use charge, and in some areas a groundwater conservation charge on top.
The good news for households is that use for domestic consumption and for agriculture is exempt from the use charge.
That exemption is not automatic in every case, though. The volume and the conditions depend on the type of use and the area.
If you intend to use groundwater for something commercial at home, a car wash, a food shop, or several rental rooms, ask the local groundwater officer on the day you lodge whether your use falls within the exemption, and how it would be charged if it does not.
Do not assume. Being billed retrospectively is far more painful than asking plainly at the start.
What you owe after the licence issues, which is the part people forget
Many people treat the licence as the finish line: file it away, use the water forever.
It is not. A licence comes with continuing duties.
- Display the licence openly at the site, rather than keeping it in a drawer.
- Install a water meter at the well and have the officer seal it.
- Report monthly usage by the seventh of the following month.
- Pay the use and conservation charges applicable to your category of use.
- Repair or replace a damaged meter within fifteen days and notify the officer.
The meter catches the most people, because owners often do not know one is required and some drillers do not fit one because nobody asked.
The cheaper path is to raise the meter when signing the drilling contract so it arrives with the job, since calling a crew back later always costs more.
On expiry. The licence carries its own expiry date. Read that date rather than relying on what somebody told you, and if you intend to keep using the well, lodge the renewal on form Nor Bor 7 before the current one expires.
That word before matters, because letting it lapse and then applying is no longer a renewal.
The method that actually works is photographing the licence into your phone and setting a calendar reminder two months ahead of the expiry date. Done once, never thought about again.
The penalty, and why an unlicensed well becomes a problem when you sell
Drilling or using groundwater without a licence carries imprisonment of up to six months, a fine of up to 20,000 baht, or both.
In reality, though, what hurts owners is usually not the criminal penalty.
It is the sale.
A careful buyer, or a bank valuing the security, sees a borehole on the land and asks for the licence. If there is none, what follows is a discount or a condition that it be sorted out before transfer.
A house with a properly licensed well, a meter, and a licence that has not lapsed is a house that sells more easily and needs less explaining.
The other side of this, which almost nobody discusses, is the abandoned well.
A disused well left open is a direct route for dirty surface water into the aquifer. It does not merely contaminate itself, it contaminates the water the whole neighbourhood draws on.
A well taken out of service should be sealed properly, not covered with a sheet of zinc and a rock and forgotten for a decade.
Critical groundwater areas and the conservation charge
Some areas have been pumped so hard that water levels have fallen and the ground has subsided, so a group of provinces carries an additional groundwater conservation charge.
That charge is 4.50 baht per cubic metre in Bangkok, Nonthaburi, Pathum Thani, Phra Nakhon Si Ayutthaya, Samut Prakan, Samut Sakhon and Nakhon Pathom.
The figure says more than it appears to.
It says that across the seven provinces of the lower Chao Phraya plain, the state would rather people did not use groundwater, and has deliberately made it expensive enough that piped supply wins.
The reason is subsidence, which does not reverse. Once clay layers compact they do not spring back when pumping stops. What follows is water that ponds more easily, drains that lose their fall, and buildings that settle unevenly.
If your house is in those seven provinces and mains water reaches it, a borehole rarely pays, both in your own costs and in what the whole neighbourhood shares.
A far better return in areas like these comes from fixing storage and pressure instead, which we covered in an above-ground tank against an underground one and sizing a water pump so it stops short cycling.
Now the part that matters more than the licence: what kind of water is it
The biggest misconception about groundwater is that clear means clean.
Plenty of groundwater is perfectly clear when drawn and turns cloudy or coloured ten minutes later, because dissolved iron has met air and precipitated.
And in the other direction, water that stays clear forever can carry arsenic or fluoride at harmful levels, with no colour, no smell and no taste to give it away at all.
So your eyes are not an instrument for measuring water quality.
They are not useless, though. Visible symptoms point fairly reliably at one set of problems. The other set can only be found by testing.
Reading the water from its symptoms
Orange-red staining in basins and toilets, a metallic taste, white laundry turning brown.
That is iron, the most common groundwater problem in Thailand. At the levels usually found it is not a health risk, but it ruins fittings and fabric and makes the water unusable in practice.
Black staining at tap outlets and in the pan, water going grey-black on standing.
That is manganese. It usually travels with iron, is harder to remove, and leaves marks that are much harder to scrub off. A house that treated the iron and still has black staining usually treated only half the problem.
Soap that will not lather, white scale on the shower head and in the kettle, tight dry skin after a shower.
That is hardness, calcium and magnesium dissolved out of limestone, common wherever the underlying rock is limestone.
A brackish or salty taste.
That is salinity, from rock salt beds or seawater intrusion, found across parts of the northeast and in coastal areas. Salinity is the hardest of all these to deal with, because ordinary filtration does not remove it.
A rotten egg smell.
Hydrogen sulphide, either from the formation or from bacteria in the well. If the smell is new in a well that behaved for years, suspect bacteria first.
Sand or sediment coming through with the water.
This one is not about the aquifer, it is about the well. It can mean a broken screen, a leaking casing, or a well that was never properly developed after drilling. It has to be fixed at the well rather than at a filter, and the longer it runs the more sand grinds away the pump impeller.
The set you cannot see, which only a laboratory finds
This is what makes testing more than an optional extra.
Arsenic has no colour, smell or taste, and causes no immediate symptoms, while accumulating and causing disease over years. Areas with a history of tin mineralisation or old mining carry higher risk.
Fluoride in the right amount helps teeth, and too much causes mottling and affects bone over the long term. High fluoride has been reported in groundwater in areas with hot springs and igneous rock.
Nitrate is a signal that surface water or waste has reached the aquifer, usually from fertiliser, animal pens or a leaking treatment system. It is particularly dangerous for infants.
Coliform bacteria may not make anybody ill by themselves, but finding them means there is a path for surface contamination to reach the well, which is valuable information, because whatever else is up there can use the same path.
The pattern worth noticing is that wells sitting close to a cesspool, a treatment tank, animal pens or a waste water outlet carry that risk far more often.
Distance between the well and the treatment system is therefore something to plan before drilling rather than to fix afterwards, because by the time a bad result comes back, nothing can be moved.
If you are about to install a new treatment system, read about siting and types in a cesspool against a prefabricated treatment tank before deciding where the borehole goes.
How to test, where, and what to ask for
Testing water is neither difficult nor as expensive as people fear.
Where to send it
- Your regional Groundwater Resources office, which runs a laboratory analysing groundwater quality directly.
- A regional health centre or the provincial public health office, for drinking suitability and bacteriology.
- A local university laboratory, or an accredited private laboratory.
What to ask for. At minimum the parameters that actually drive decisions: pH, turbidity, colour, hardness, total dissolved solids, iron, manganese, chloride, nitrate, fluoride, arsenic and coliform bacteria.
If you intend to drink it, say so plainly, so the laboratory reports against drinking water criteria rather than handing you bare numbers to find a benchmark for yourself.
How to take the sample. This decides how much the result is worth, more than people realise, because a badly taken sample gives a wrong answer that you then use to buy a filter.
- Use the bottle the laboratory supplies, or a clean bottle to their specification. Not a rinsed soft drink bottle.
- Run the tap for several minutes first to clear water standing in the pipes, because standing water is not well water.
- Sample from the tap nearest the well and upstream of any filter, if you want to know what the raw water is.
- For bacteriology use the laboratory's sterile bottle, never rinse it yourself, and keep the sample cold in transit.
- Deliver it as fast as possible, bacteriological samples especially, since they have a very short life.
The other thing worth doing that almost nobody does is testing again.
Groundwater is not constant through the year. Many wells differ between the end of the dry season and the middle of the rains, so a single test in a single month describes only that day.
Test annually at least, and immediately whenever taste or colour changes, after flooding in the area, or after work on the well.
Choose treatment from the test result, not from the sales pitch
This is where the most money disappears for the least return.
Every kind of treatment solves a different problem, and the one that solves problem A does nothing at all for problem B.
Iron and manganese need aeration or oxidation to precipitate first, then filtration through media suited to the job. Fitting an ordinary sediment cartridge blocks it within days and fixes nothing.
Hardness needs ion exchange, which means salt to top up and a regeneration cycle. Not a fit and forget system.
Salinity, arsenic, fluoride and nitrate are dissolved, and ordinary filtration does not remove them. That needs something like reverse osmosis, which produces good water alongside a reject stream, so it is usually fitted at the drinking and cooking points rather than for the whole house.
Bacteria need disinfection, chlorine or an ultraviolet lamp, but more importantly they need somebody to find how they are getting in. Disinfecting at the outlet without closing the entrance is treating the symptom forever.
Sand and sediment are fixed at the well, not at a filter.
The right order is to test first, then take the result to whoever sells treatment, rather than have a salesman look at the water and prescribe a package.
A good supplier asks to see the analysis. One who answers instantly without looking at anything is selling the same package to every house.
And once a system is in, remember it carries running costs: media to replace, salt to top up, cartridges with a service life. That number belongs in the decision from the start, not discovered in year two.
How a neglected well fails
Boreholes do not last forever, and they rarely fail suddenly. They degrade until one day there is not enough water.
Yield falling gradually can be a screen clogging with scale or with the slime that iron bacteria produce, or a genuine drop in the water level from everything in the area pumping at once.
A pump cycling oddly or running hot can mean it is working at a water level lower than it was designed for, which eats its life quickly.
More sand than before signals a screen or casing starting to fail, and it gets more expensive the longer it runs.
A sudden change in water quality in a well that has been stable for years means stopping drinking it and testing, particularly if the change followed flooding or nearby construction.
The habits worth keeping are few.
Keep the ground around the wellhead clean and draining, so water never ponds over the well. Keep the cap sealed. Store no chemicals, fertiliser or fuel near it. And note the meter reading and how the pressure feels from time to time, so a trend shows itself before it becomes a failure.
If you are buying a house that already has a borehole
This comes up more often than people expect, especially outside town and on garden plots.
What to ask for and look at:
- Both licences and the expiry date printed on them, rather than an assurance that they were obtained once.
- The well log and the real depth, including the level the pump is set at.
- The most recent water analysis. If there is none, assume nothing is known about this water, and test before transfer.
- Repair history. How many pumps, and when the well was last cleaned or blown out.
- Distance from the treatment system and any animal pens, which you can judge with your own eyes on the viewing.
- Whether mains water reaches the property, because a house with both options carries far less risk.
If the well is unlicensed, that is not a reason to walk away, it is a point to negotiate. Settle in the contract who will deal with it, before or after transfer, and what happens to the price and to the agreement if it cannot be resolved.
What belongs in that contract, and how to read one, is in what to read in a sale and purchase contract.
Frequently asked questions
Does a well on my own land for my own use need a licence?
Yes, if it is deeper than fifteen metres. The law does not exempt houses or private use, and two licences are needed, one to drill and one to use.
What about a concrete ring well in the garden?
If it is no deeper than fifteen metres it is not groundwater under the Groundwater Act B.E. 2520 and needs no drilling licence. It deserves more caution about surface contamination than a deep well, though, because it sits closer to the dirt.
What do the fees add up to?
Ten baht per application form, then a licence fee by bore size: 100 baht for 2 to 3 inches, 500 baht for 4 to 6 inches and 1,000 baht for 8 inches and above. The drilling itself is a separate and much larger cost.
Does a household pay a monthly water charge?
Use for domestic consumption and agriculture is exempt from the groundwater use charge, but the conditions and volumes depend on the type of use and the area. If it will serve anything commercial, ask the local groundwater officer on the day you lodge.
What is the penalty for not applying?
Up to six months imprisonment, a fine of up to 20,000 baht, or both. In practice it also becomes a problem at sale, because buyers and banks ask for the licence.
Groundwater looks clear, so can I drink it?
No. Clarity says nothing about arsenic, fluoride, nitrate or bacteria, none of which have colour, smell or taste. Only a laboratory can tell you.
How often should the water be tested?
At least once a year, and immediately if colour or taste changes, after flooding in the area, or after work on the well, because groundwater quality shifts with the season and with what happens around it.
In short
- Deeper than fifteen metres is groundwater in law, and needs a licence even for a private house using it itself.
- Two licences: drilling on form Nor Bor 1, use on form Nor Bor 2.
- Apply to the local groundwater officer, which sits in a different office depending on the province. Telephone first.
- Ten baht per application, 100 to 1,000 baht for the licence by bore size, with the drilling itself the large cost and worth three quotations.
- Duties continue afterwards: display the licence, fit a meter, report usage by the seventh of the following month.
- Renew on form Nor Bor 7 before the current licence expires, with a reminder set two months out.
- Drilling or using without a licence: up to six months, up to 20,000 baht, or both.
- In the seven provinces charging 4.50 baht per cubic metre in conservation charges, a new borehole rarely pays if mains water is available.
- Clear is not clean. Arsenic, fluoride, nitrate and bacteria have no colour, smell or taste, so test.
- Buy treatment from the analysis, never from somebody who did not ask to see it.