When Koh Samui rations its water, a hotel or villa can do five things: store more water, book trucked water early, cut process use, run a reverse osmosis system for the hours the line flows, and make drinking water from the air so that the water guests drink no longer depends on the pipeline. The Thaiger reported zoned supply and residents buying trucked water in the 2023 and 2024 dry seasons, and rationing returned in 2026. Minairal is based in Bo Phut and lives with the same supply.
Why does Koh Samui run short of water in the dry season?
The island depends on its reservoirs and on an undersea pipeline from the mainland, and demand peaks in the same months the rain stops. When reservoirs fall, the Provincial Waterworks Authority rotates supply between zones, and properties on high ground are the first to see their taps run dry. The published figures and the history of the last episodes are set out in our earlier article on what the Koh Samui water shortage means for hotels and villas.
This article does not repeat that background. It is a working plan: what to do before the dry season, what to do once rationing starts, and which option covers which need.
What are the options when the mains is rationed?
A property uses water in two ways, and no single option covers both. Process water is showers, laundry, pools and gardens: large volumes that must come from the mains, from tanks or from trucks. Drinking water is a small volume that guests taste and remember. The table sets the options side by side.
| Option | Covers | Keeps working during rationing? | What to watch |
|---|---|---|---|
| Storage tanks | Process water for a few days | Yes, until they run dry | Capacity, cleaning, pumps and a float valve that fills whenever the mains runs |
| Trucked water | Process water, topped up | Yes, while trucks are available | Price rises and waiting times lengthen when every property is calling the same suppliers |
| Bottled water | Drinking water | Yes, while deliveries arrive | Every bottle arrives by boat and truck on roads busy with water trucks; storage space; plastic |
| Reverse osmosis on the mains | Drinking water from the line | Only while the line runs | Needs a stable supply; pair it with a tank or use it in zones that stay supplied |
| Atmospheric water generator | Drinking water from the air | Yes, it needs electricity and humidity, not a water line | Litres a day per unit; place units where the air is humid, not in cold rooms |
The first two options are the general manager's answer for process water. The last three are the answers for drinking water, and only the last one is independent of the pipeline, the reservoirs and the delivery schedule.
What should a hotel do before the dry season?
- Know the numbers. Metered consumption per month, tank capacity in days of autonomy, and the drinking water volume: two litres per person per day, staff included. A 50-room hotel with 100 guests and 40 staff needs about 280 L of drinking water a day.
- Service the tanks. Clean them, check the float valves and the pumps, and confirm the tanks fill automatically during the hours the mains runs.
- Agree trucked water terms in writing. Price per load, lead time and a priority slot, signed before the first week without rain.
- Cut process use where guests will not notice. Low-flow fittings, a towel and linen policy that is applied rather than printed, and garden watering at night.
- Take drinking water in-house. Install atmospheric water generators in the housekeeping pantries, the restaurant and the staff area, and give them a few weeks to settle into the routine before the first cut. Each unit plugs into a socket; there is no plumbing to plan.
What should a hotel do once rationing starts?
- Post the zone schedule from the waterworks in the engineering office and fill the tanks during every supply window, even at night.
- Tell guests in one calm sentence at check-in: the island is on a rotation, the hotel stores water, and drinking water is produced on site.
- Move laundry to the hours the mains runs, or to an off-site laundry on a supplied zone.
- Serve drinking water from the generators in reusable glass bottles and carafes, and keep a small bottled reserve for the day a unit is in maintenance.
- Log tank levels twice a day. The log tells you when to call the truck and, next year, how many days of storage you really need.
How does an atmospheric water generator keep drinking water flowing?
It draws humid air through a filter, cools it below its dew point so the vapour condenses, then filters the water, protects it with UV and restores calcium, magnesium, potassium and sodium. It needs a socket and humid air, both of which Koh Samui has when the taps do not run. Minairal's Air range produces 13, 16 or 22 L a day on average per unit, with 30 L maximum for the Air Stand Pro, for relative humidity between 30% and 80% at an average temperature of 25°C.
A 50-room hotel does not put a dozen units in one room. It spreads them across the points where water is actually drawn: a pantry per floor to fill the room bottles, one in the restaurant, one by the pool, one in the staff canteen. The configuration is set at the site assessment and described on our hotels and resorts page. For the machines themselves, see the Air range.
What about a managed villa?
A villa follows the same plan at a smaller scale. One tank with a working float valve, a trucked water contract if the villa sits on high ground, and one Air Stand or Air Stand Pro in the kitchen for the household and its guests. At two litres per person per day, a four-bedroom villa with eight people needs 16 L a day, which one unit covers on average.
Frequently asked questions.
Does an atmospheric water generator work during a water cut?
Yes. It has no water inlet, so a mains interruption does not affect it. It needs electricity, about 370 to 500 watts while producing, and humid air.
Can it replace the trucked water?
No. It makes drinking water, measured in litres a day per unit, not the thousands of litres a day that showers, laundry and pools use. It takes the drinking water off the truck and off the boat; the tanks and the truck still cover the rest.
How quickly can a hotel in Koh Samui be equipped?
Minairal's head office, showroom and service centre are in Bo Phut, with technicians on payroll and parts on the island, and the response time is 4 hours on average. A free one-week trial lets a property test a unit in its own pantry before the dry season.
Details for the island are on our Koh Samui page. To test a unit in your property before the next dry season, request the free one-week trial.
