Cyclone season in French Polynesia: how can you secure your access to drinking water?

In French Polynesia, the cyclone season is a yearly reminder of how important it is to prepare for extreme weather events. Violent winds, heavy rain, flooding, power cuts: a cyclone can disrupt many essential services, starting with the drinking water supply.

In October 2026, the Polynesian authorities organized a crisis management exercise called "Cyclone 2026", bringing together emergency services, water and electricity network operators and healthcare facilities. The goal: to test the territory's ability to cope with a major event affecting several archipelagos.

For residents and local authorities alike, this exercise is a reminder of one reality: access to drinking water should not be taken for granted in a crisis.

So how much water should you keep at home? How do you protect a water tank? Can you drink tap water after a cyclone? And what solutions exist to maintain access to drinking water when the network no longer works?

Here are the essential precautions to take before, during and after the cyclone season in French Polynesia.

2026-2027 cyclone season: why prepare as early as October in French Polynesia?

In French Polynesia, cyclone vigilance mainly concerns the hot, wet season. The period generally used for preparation runs from November to April, although the risk and its intensity vary from one archipelago and one year to the next.

Météo-France Polynésie française points out that the cyclone watch period in practice runs from November to March, in the absence of any threat identified in the short term.

The risk is not the same in Tahiti, Moorea, Bora Bora, the Tuamotus, the Gambier Islands or the other archipelagos. Ocean and atmospheric conditions strongly influence the formation and track of tropical systems.

But even when no cyclone directly hits an island, episodes of heavy rain can cause flooding, landslides and disruption to infrastructure.

In October 2026, the "Cyclone 2026" exercise simulated precisely such a complex situation affecting several archipelagos, with challenges for transport, telecommunications, electricity and water.

Preparation should therefore not start when an alert is announced. For families, municipalities and isolated facilities, the weeks before the cyclone season are the right time to check installations and build up reserves.

Why is drinking water particularly vulnerable in the Polynesian islands?

French Polynesia has one major particularity: its territory is made up of islands and atolls scattered over a vast ocean area.

This geography makes water supply very different from one island to another.

According to the Environmental Health Center of French Polynesia, water resources can come from boreholes, springs, rivers, rainwater harvesting or seawater desalination.

On some high islands, supply relies on water catchments and distribution networks. On the atolls, where freshwater resources are limited, rainwater harvesting and storage often play a major role.

A cyclone can weaken each of these supply methods.

Damaged networks

Violent winds, falling trees, landslides or flooding can damage pipes, catchments and distribution equipment.

A burst pipe or a loss of pressure can also allow contaminated water to enter certain parts of the network.

Power cuts

Some pumping, treatment and distribution systems depend on electricity.

A prolonged outage can therefore interrupt the water supply, even when the resource itself remains available.

Deterioration in the quality of resources

Heavy rain can carry suspended solids, debris, micro-organisms and various contaminants into rivers or catchments.

Water tanks can also be affected if their lids, connections or collection systems are damaged.

On the atolls, marine flooding poses an additional risk: salt water can reach storage facilities or certain freshwater resources.

Finally, when sea and air links are cut, delivering bottled water or emergency equipment can become more difficult.

This is why preparation must combine three elements: having a reserve, protecting its quality and planning a suitable backup solution.

Before a cyclone: how much drinking water should you keep at home?

Building up a reserve of drinking water is one of the first steps to take before the cyclone season.

A common planning basis for emergency kits is around 3 liters of water per person per day for drinking and food preparation, for at least 72 hours.

This quantity is a planning minimum. It does not cover all hygiene, cleaning or sanitation needs. It should also be increased depending on the heat, medical needs and the make-up of the household.

For example:

Household size	Basic reserve for 3 days
1 person	9 liters
2 people	18 liters
4 people	36 liters
6 people	54 liters

On remote islands, where restoring services or receiving supplies can take longer, planning for greater self-sufficiency may be wise where possible.

In all cases, follow the recommendations of the High Commission, the municipality and the local health authorities, who may set quantities suited to the situation.

How should you store your reserves properly?

A reserve is only truly useful if the water remains fit to drink.

To limit the risks:

• Choose bottled water or drinking water kept in food-grade containers.
• Use clean, closed containers reserved for water storage.
• Keep them away from sunlight, excessive heat and chemicals.
• Respect the shelf-life dates and the manufacturer's recommendations.
• Avoid mixing new water with older water of uncertain quality.
• Label drinking water separately from water reserved for non-food uses.

For households with a water tank, checking the tank and its connections should also be part of the preparations.

Water stored in tanks in Polynesia: how can you preserve its quality?

In French Polynesia, tanks and reservoirs are an important way of having water when supply is irregular or when a home uses a stored resource.

But two very different situations must be distinguished: storing water that is already drinkable and storing raw water, particularly harvested rainwater.

The quality of stored drinking water can change

Water that was initially drinkable can be exposed to contamination risks if the tank is poorly maintained, insufficiently protected or connected to a degraded circuit.

Points to watch include:

• The tightness of the lid and connections.
• Any sediment at the bottom of the tank.
• Protection against animals, insects or debris getting in.
• The condition of the pipes between the tank and the home.
• The duration and conditions of storage.

Regular inspection and maintenance help reduce some risks. An analysis may be needed to check that the water remains fit for consumption.

Harvested rainwater is not drinkable by default

On the atolls, rainwater harvesting is an important practice. However, the Environmental Health Center of French Polynesia points out that harvested, untreated rainwater is not considered drinkable.

As it runs off a roof and then sits in a tank, it can come into contact with dust, animal droppings, organic matter or micro-organisms.

It should therefore not be treated as drinking water from the network simply because it looks clear.

Making it drinkable requires a study of the resource and a suitable treatment process, with verification of the quality of the water obtained.

Can you filter tank water for the whole house?

Yes, in some configurations, but the choice of system depends above all on the origin and quality of the stored water.

For a tank supplied with mains water that was initially drinkable, centralized filtration can be considered to treat certain contaminants or improve the taste and odor of the water distributed in the home.

At FLX Water, the Export range includes the FiltraHome Box Mini and the classic FiltraHome Box.

These systems use water pressure to provide centralized filtration, without the filtration unit needing its own power supply.

The FiltraHome Box Mini is designed for drinkable mains water. Its use on stored water must therefore be validated beforehand according to the quality of that water and the installation conditions.

The classic FiltraHome Box has additional pre-filtration stages, but this does not mean it can automatically make any rainwater, borehole water or tank water drinkable.

Raw water, water contaminated after a flood or water whose drinkability is unknown requires a specific diagnosis. Residential filtration must not be used to get around an official "do not drink" notice.

During a cyclone: how can you stay self-sufficient in drinking water?

When a cyclone alert is issued, the absolute priority remains people's safety and compliance with official instructions.

Météo-France Polynésie française distinguishes several levels of vigilance and alert, including the warning, the pre-alert and the cyclone alert.

Once the authorities have ordered people to stay indoors or take shelter, do not go out to look for water or work on an exposed installation.

If the water network is cut off, use the drinking water reserves built up before the event first.

Keep them for drinking, food preparation and essential needs. Other uses must be adapted to the quantity available.

It is also recommended to:

• Close containers properly after each use.
• Avoid touching the inside of containers or their openings.
• Not mix water of unknown quality with the drinking water reserve.
• Not use potentially contaminated water to prepare baby bottles.
• Follow information from the municipality and health authorities about mains water.

Filtration installed in the home does not guarantee self-sufficiency if the water stops arriving or if the pressure needed for it to work is no longer available.

This is an important distinction: filtering water and having an independent reserve are two complementary but different functions.

After a cyclone: can you still drink tap water?

After a cyclone has passed, water returning to the tap does not necessarily mean its quality has been fully restored.

Infrastructure may have suffered damage, infiltration or major pressure variations. Catchments can also be affected by heavy rain.

The first step is therefore to check communications from the municipality, the water operator and the health authorities.

Depending on the circumstances, instructions may require you to boil the water, keep it for certain uses only or not drink it at all.

It is essential to follow the exact instruction.

Boiling water can reduce certain microbiological risks, but it does not remove chemical contaminants, dissolved salts or all the substances that may be present after flooding or pollution.

Water contaminated with hydrocarbons, chemicals or seawater does not automatically become drinkable after boiling.

Likewise, clear water is not necessarily safe, and cloudy water should not be drunk until the cause of the problem has been identified.

If your tank has been submerged, damaged or exposed to floodwater, do not assume its contents are still drinkable. Inspection, appropriate cleaning and testing may be needed before it is put back into service.

How can you produce drinking water when the network is down?

When an interruption lasts, the reserves built up before the event may become insufficient.

Producing drinking water from a locally available resource can then provide continuity, provided a suitable process is used.

In particular, a distinction should be made between:

• Mains water that was initially drinkable: its quality must be confirmed if the network has been damaged.
• Raw fresh water: from a spring, river or reservoir, it may require several treatment stages.
• Stored rainwater: it requires appropriate assessment and treatment before being used for drinking.
• Seawater or brackish water: it requires a specific desalination process.

Mechanical filtration, activated carbon, disinfection processes and other technologies can meet different needs. No process should be considered universal.

In an emergency, the choice of equipment must take into account the quality of the incoming water, the contaminants to be reduced, the flow rate needed, the resources available and the quality checks that can be carried out on the output.

Municipalities, schools and remote islands: anticipating a supply disruption

For municipalities and facilities open to the public, preparation is not limited to storing a few bottles of water.

A cyclone can simultaneously cut transport, communications, electricity and the water supply.

In remote archipelagos, the distance between islands can make it harder for equipment and reinforcements to arrive quickly.

It is therefore useful to prepare a genuine continuity plan for the drinking water supply.

This plan can include:

• Identifying daily drinking water needs.
• Taking stock of available reserves and how long they will last.
• Protecting catchments, tanks and storage equipment.
• Identifying alternative resources that can be used in an emergency.
• Having treatment equipment compatible with these resources.
• Organizing distribution to residents or users.
• Defining how the quality of the water produced will be checked.

For a school, a shelter or a municipality, the aim is to have a response ready before weather conditions make travel difficult.

This approach is particularly important for territories where infrastructure and freshwater resources are limited.

FLX Water and Hanavai: drinking water solutions for French Polynesia

FLX Water develops water filtration and treatment solutions for a range of uses, from residential to crisis management.

In French Polynesia, the company works with its local partner Hanavai, with whom it shares the goal of improving access to quality water across the territory.

The solutions offered meet two distinct needs: treating water in homes and producing drinking water in emergencies.

FiltraHome Box Mini and classic: residential filtration

For households, the FiltraHome Box Mini and classic FiltraHome Box make it possible to consider centralized filtration of the water distributed in the home.

They combine 0.1 µm hollow-fiber technology, electro-adsorption and activated carbon, with pre-filtration configurations suited to each unit.

They work using water pressure, without the filtration unit needing its own power supply.

These solutions can be considered for homes supplied with drinkable mains water, including when it passes through tank storage, provided the water quality, pressure and compatibility of the installation have been checked beforehand.

However, they are not, by default, stand-alone solutions for making rainwater or an unknown raw resource drinkable.

The Crisis Solution: treating a freshwater resource without electricity

For emergencies, FLX Water also offers a Crisis Solution designed to produce drinking water from certain freshwater resources, after their compatibility has been assessed.

The system has a manual pump and works without electricity or added chemicals in its filtration process.

Its nominal flow rate can reach 1,000 liters per hour, depending on operating conditions.

This capacity can be valuable for local authorities, schools, humanitarian organizations or isolated sites wishing to plan a backup solution.

The technology has notably been deployed at a school in the Gambier Islands, in partnership with Hanavai.

The Crisis Solution cannot desalinate seawater. It must be used with a suitable freshwater resource, after technical validation, and accompanied by checks to verify the quality of the water produced.

In a cyclone context, its main advantage is that filtration can run without depending on a power supply.

Checklist: how should you prepare your drinking water before the cyclone season?

Before the cyclone season begins, a few checks can make a big difference.

For households

• Build up a sufficient reserve of drinking water for several days.
• Adapt quantities to the number of people and the household's specific needs.
• Check that containers are clean and watertight.
• Inspect tanks, lids and connections.
• Identify the origin of stored water and check its quality.
• Know the cyclone alert instructions and the official information channels.
• Plan a backup solution in case of a prolonged outage.

For municipalities and facilities

• Assess drinking water needs in a degraded situation.
• Check stocks and available storage capacity.
• Identify alternative resources and their limitations.
• Plan treatment equipment compatible with these resources.
• Anticipate maintenance and consumable needs.
• Organize distribution and health monitoring procedures.
• Train the people responsible for putting the equipment into service.

The most effective preparation is the one carried out before the alert. Once travel is restricted or networks are cut, the options for intervention become much more limited.

In French Polynesia, drinking water self-sufficiency is prepared before the crisis

The cyclone season highlights a key issue for the Polynesian islands: having quality water depends not only on the presence of a resource, but also on how it is protected, stored, treated and distributed.

For households, the priority is to prepare drinking water reserves, maintain tanks and know the limits of the equipment installed.

For local authorities and isolated sites, the challenge is broader: anticipating a prolonged network outage and having a continuity solution suited to local resources.

Through its partnership with Hanavai, FLX Water supports water treatment projects in French Polynesia, whether to improve the quality of water distributed in a home or to prepare an independent system for crisis situations.

Because when a cyclone strikes, the best solution is the one that was studied, sized and prepared before the emergency arose.

Frequently asked questions

When does the cyclone season start in French Polynesia?
Preparation generally covers the period from November to April. Météo-France Polynésie française places the usual cyclone watch period from November to March in practice. The risk varies with climate conditions and from one archipelago to another.

How much water should you store before a cyclone?
A basic planning figure is around 3 liters of water per person per day for drinking and food preparation, for at least three days. This quantity should be increased according to needs and official local instructions.

Can you drink water from a tank after a cyclone?
Not without making sure of its quality. If the tank has been flooded, damaged or exposed to contamination, the water should not be considered drinkable by default. Follow health instructions and have the installation checked if necessary.

Can a FiltraHome Box treat tank water?
An installation can be considered when the tank contains mains water that was initially drinkable, subject to compatibility and quality checks. The FiltraHome Box Mini is not designed to make rainwater or untested raw water drinkable directly.

How can you filter water without electricity during an outage?
Some systems work without their own power supply. However, pressurized residential filtration requires a water supply and sufficient pressure. A crisis solution with a manual pump can offer more self-sufficiency, provided a compatible resource is available.

Can seawater be made drinkable with the FLX Water Crisis Solution?
No. The Crisis Solution is designed for certain freshwater resources. Seawater requires a specific desalination process.

Sources

• Météo-France Polynésie française – What is the cyclone alert?: how the alert system works and usual vigilance periods.
• Météo-France Polynésie française – October 2026 seasonal forecasts: climate context and seasonal forecasts.
• Puublik / Tahiti Nui Télévision – 2026-2027 cyclone season: Polynesia tests its ability to face the worst: the "Cyclone 2026" exercise and preparation of essential infrastructure.
• Environmental Health Center of French Polynesia – Networks and public fountains: origins of water resources, treatment and specific features of supply in the archipelagos.
• Environment Directorate of French Polynesia – Water policy: challenges of preserving the resource and ensuring access to quality water.
• Health Directorate of French Polynesia – Health risk prevention: precautions regarding drinking water and risks linked to heavy rain and flooding.
• FLX Water – FiltraHome Box Mini: characteristics and compatibility conditions of residential filtration.
• FLX Water – FiltraHome Box: characteristics of the centralized filtration system.
• FLX Water – Crisis Solution: mechanical filtration solution designed for emergencies.