The 2026 (B.E. 2569) Lak Si Flood: What Was Reported

According to Thai PBS on 26 September 2026, the BMA measured 12.5 centimetres of standing water on Ngamwongwan Road, which began collecting at 22:25 on 25 September, and 10.3 centimetres on Chaeng Watthana Road. Thai PBS also reported water about 50 centimetres deep in front of homes in a community near Thung Song Hong Metropolitan Police Station.

On 27 September 2026, Thai PBS reported that Vibhavadi Rangsit Road in front of the Thai PBS building was still flooded too deep for small cars along a stretch of about 2 kilometres, with road-improvement works obstructing drainage and slowing the water's retreat.

Across Bangkok, Thai PBS reported more than 300 millimetres of rain in about 48 hours over 25 to 26 September 2026, and all 50 districts were declared disaster areas on 26 September. DDPM reported on 6 October 2026 that about 329,000 Bangkok households were affected. Nationally, DDPM reported, as of 06:00 on 7 October 2026, that 27 provinces plus Bangkok were affected, covering 123 districts, 984 subdistricts and 1,154,875 households, with more than 3.1 million people affected. These figures reflect the dates of the reports and change daily; follow the Lak Si District Office and the BMA for updates.

Lak Si mixes wooden community houses, shophouses, townhouses, housing estates, condominiums and large government offices. Single-storey homes and houses with ground floors below road level are hit first, and many families move upstairs together until the ground floor dries.

A Typical Scenario: Home from Temporary Shelter, and Everyone Starts Coughing

Example case written to illustrate a common post-flood situation. It is not an interview with any Lak Si resident.

Ann's family lives in a two-storey house in a community near Thung Song Hong: her parents in their sixties, her mother with diabetes, and her kindergarten-age son. The night water reached the front door, the family took her parents to a temporary shelter near a relative's home for several days. Many people slept together in a large hall there, several were coughing and sneezing, and everyone shared toilets.

When the water outside fell, the family came home. The ground floor was still damp with a thin film of mud, so they laid mattresses in the upstairs shared room, kept the windows shut because of on-and-off rain, and slept all five together with the air conditioner on. Two days later Ann's father had a sore throat, low fever and cough, followed by Ann herself with body aches and a weakened sense of smell.

Ann tested everyone with ATK kits. Her father's and her own showed two lines. She called a health service, because her mother is over sixty with diabetes, part of the high-risk group Thais call "group 608". The advice: separate the infected from her mother and son, wear masks when close, open windows, wash hands often, and take her mother to a doctor right away if symptoms appear.

After everyone recovered, the upstairs shared room smelled stale, the curtains and rug held sweat and damp, and the ground floor smelled of earth and drains. The right order is to wash the mud off downstairs, wipe high-touch surfaces, wash bedding, blankets and curtains, dry every room completely, and only then consider ozone for the shared room and ground floor on a day when everyone is out, to help reduce airborne germs and lingering odour.

What Is COVID-19 (SARS-CoV-2)?

COVID-19 is a respiratory infection caused by the coronavirus SARS-CoV-2. It still circulates in communities and keeps changing, so people who were infected or vaccinated before can catch it again. Most cases today are milder than in the early pandemic, but older adults and people with chronic illness still need extra care.

How does COVID-19 spread?

• Respiratory droplets and particles released when an infected person coughs, sneezes, talks, sings or breathes nearby. This is the main route.
• Small particles lingering in the air of closed, poorly ventilated rooms where people spend long periods together, such as shared bedrooms, shelter halls or cars with windows up.
• Hands touching contaminated surfaces and then the nose, mouth or eyes. This is less common than airborne spread, but handwashing and wiping shared touch points still matter.

People can spread the virus shortly before symptoms start, and some have such mild symptoms they do not realise they are infected. That is why days in a closed shared room let it pass through a household.

Why ventilation matters most

The WHO and many health agencies stress that letting outside air replace room air greatly reduces the amount of virus floating in it. A sealed room with a wall-mounted air conditioner that recirculates the same air is riskier than one with open windows or an exhaust fan. After floods, many families keep rooms shut against rain and mosquitoes, so they need to ventilate whenever they can.

Why Lak Si Homes Need Extra Care with COVID-19 in Shared Rooms

Floodwater does not carry COVID-19 directly; it spreads person to person through the airways. But the flood period and its aftermath create conditions that help it spread.

• Crowding at shelters or relatives' homes, with many people sleeping close together and sharing toilets and utensils.
• Sleeping together in one room at home while the ground floor is wet or muddy.
• Windows shut and air conditioning all day, so airborne virus builds up.
• Exhaustion and stress from hauling belongings, cleaning, short sleep and money worries.
• Older relatives in constant close contact with younger family members, making isolation hard.
• Hard trips to the doctor while Vibhavadi Rangsit Road in front of Thai PBS stayed deeply flooded for days.
• Damp and mould at home, which do not cause COVID-19 but make people with allergies or lung disease cough more and blur the picture of what is causing symptoms.

COVID-19 Symptoms, ATK Testing and Who Is Most at Risk

Common symptoms people search for include:

• Fever, chills or feeling hot
• Cough, sore throat, blocked or runny nose
• Body aches, headache, fatigue
• Loss of smell or taste
• In some people, nausea, loose stools or breathlessness

These overlap heavily with flu and colds. A self-administered ATK test, used as the kit instructs, helps with screening. If the result is negative but symptoms continue, retest as the kit or a health worker advises. If positive, separate from others at home, wear a mask and contact a health service.

High-risk groups ("group 608")

• Adults aged 60 and over
• People with chronic respiratory disease, heart and vascular disease, chronic kidney disease, cerebrovascular disease, cancer, diabetes or obesity
• Pregnant women
• People with weakened immunity, and young children with underlying conditions

When to see a doctor quickly

Seek care promptly for breathlessness, difficult breathing, chest tightness, drowsiness or confusion, pale or bluish lips, a high fever that will not come down, inability to eat or drink, or steadily worsening symptoms. High-risk people should contact a health service as soon as they test positive, because early treatment may be considered. If you waded through floodwater and develop high fever with severe calf pain, tell the doctor, since early leptospirosis can look similar. This article is general information, not treatment advice.

Shared-Room Hotspots After the 2026 Lak Si Flood

• Mattresses, pillows, blankets and sheets laid out together on the floor. Wash and sun-dry completely.
• Bags, clothes and blankets brought back from the shelter. Wash everything before putting it away.
• Air conditioners and filters that recirculated the same air all day and gathered dust and moisture.
• Remotes, phones, door handles, light switches and stair rails touched by everyone.
• Dining tables and utensils shared while someone was sick.
• Curtains, rugs and fabric sofas that absorb particles and musty smells.
• The shared bathroom, including basins and taps.
• Ground-floor walls and floors where water entered, with mud, tide marks, mould and drain smells from street flooding.

The Impact on Lak Si Families

Older and chronically ill relatives face higher risk, and isolation is hard when everyone shares a room; some people also feel tired or keep coughing for a while after recovery. Infected workers lose days on top of leave taken for flood cleanup, small community shops may close, and children miss school. A room that served as a sickroom and still smells of flood damp does not feel like home, especially when an elderly parent needs to move back in.

Why Wiping, Air Conditioning or Air Freshener Are Not Enough

• The main problem is in the air. Wiping tables and handles is still necessary, but COVID-19 spreads mainly through air, so a closed room needs ventilation too.
• Home air conditioners recirculate. Most wall units do not bring in outside air, so moisture from indoor drying and musty smells keep circulating.
• Fragrance only masks. The source remains, and strong scent can irritate a sore throat.
• Sealing a damp ground floor. Mould can appear within days. The CDC advises cleaning and drying within 24 to 48 hours after floodwater recedes.
• Unwashed shelter belongings. Tired families often put damp blankets and clothes straight into wardrobes.
• Disinfectant on mud. Disinfectants work poorly on dirty surfaces, so wash with clean water and detergent first.

Shared-Room Ozone After the 2026 Lak Si Flood with WHD: How It Helps

World Health Disinfection's residential ozone disinfection service releases ozone gas (O3) into a closed, empty room. Ozone is a strong oxidiser that reacts with micro-organism structures and odour molecules, then breaks down back into oxygen (O2), leaving no chemical film. As a gas it reaches the room's air, corners, under beds and behind wardrobes.

According to the company's certification, based on testing by Thailand's Department of Medical Sciences and Intertek (UK), the service eliminates virus, bacteria and mould groups at 99.99%. The service page does not list a SARS-CoV-2-specific test, so we describe it as belonging to the virus group the service targets. Detailed test data can be requested from WHD via the certificates page, by phone or on LINE.

Ozone is not COVID-19 treatment, does not replace vaccination and does not protect anyone from a person who is still sick at home. The main protections remain isolation, masks, handwashing, ventilation and vaccination as advised by a doctor. Ozone is a supporting step after recovery and cleaning, to help reduce germs in the air and on hard-to-reach surfaces and to cut musty odour in the shared room and flooded ground floor.

WHD's post-flood shared-room ozone process

1. Survey and assessment. The team asks about house size, rooms, water height, odour spots and when the sick recovered, by phone, LINE or on site.
2. Clean and dry first. Remove mud downstairs, wipe shared touch points, wash bedding, curtains and shelter belongings, discard soaked absorbent items such as foam mattresses, rugs or swollen mouldy gypsum, and dry every room.
3. Empty and seal the room. All people, pets and plants leave; doors and windows close; the air conditioner is switched off as advised.
4. Ozone cycle. Typically about 30 minutes per zone, depending on size and condition.
5. Rest and ventilate. The ozone breaks down, then doors and windows open for the time the technician sets.
6. Re-entry only when the technician confirms it is safe, followed by regular ventilation.

Is ozone dangerous? Safety rules

• High-concentration ozone irritates the eyes, nose, throat and lungs. No people, pets or plants in the room during treatment.
• People just recovered from COVID-19, older adults, people with lung disease or asthma, and children should wait until ventilation is complete.
• Rooms must be clean and dry first. Ozone does not replace removing mud, discarding soaked materials or fixing leaks.
• Ozone does not penetrate deep into mattresses, sofas or waterlogged walls; soaked, mouldy materials should go.
• Anyone unwell must see a doctor. Ozone treats the home environment, not disease.

10 Reasons Lak Si Homes Should Consider Shared-Room Ozone After the 2026 Flood

1. Treats the whole room's air where the family slept together.
2. Suits former sickrooms, preparing them after recovery and cleaning for an older parent to move back in.
3. Helps cut musty and drain odour from the flooded ground floor, the top reason people search for ozone odour removal.
4. Targets virus, bacteria and mould groups, per the company's certification citing 99.99%.
5. No residue. Ozone reverts to oxygen, leaving nothing on mattresses or toys.
6. Reaches hard-to-wipe spots such as under beds, behind wardrobes and ceilings.
7. Short treatment time: about 30 minutes per zone plus rest and ventilation.
8. Follows cleaning and drying as the final recovery step.
9. Useful for rentals, shophouses and condos in Lak Si preparing rooms for new occupants.
10. Consult first on 065-556-6294 or LINE @whd268, or read the ozone service page.

Example Case: A Shophouse That Is Both Store and Home

Example case written to illustrate a common situation. It is not a review by any customer.

Lek runs a grocery in a two-storey shophouse along Ngamwongwan Road: shop downstairs, a shared room upstairs where four family members sleep. When water seeped into the ground floor, stock went upstairs, and the bedroom became storeroom and sleeping space at once.

After the water fell, her eldest daughter, who had helped neighbours move belongings, developed fever and sore throat and tested positive on ATK. She slept apart in a small room by the balcony, wore a mask and used a separate bathroom where possible. Lek washed the ground floor, threw out soaked cardboard, scrubbed floors and walls, and dried the shop with open doors and fans for days.

Once everyone recovered, the upstairs room still smelled stale from packed stock and indoor laundry, and the shop carried a faint drain smell. The ozone team advised moving food stock out of treatment zones, closing the shop for a day, getting everyone out of the building, treating each floor zone by zone, then ventilating before re-entry. Ozone came after patient care, cleaning and drying, not instead of them.

Checklist: COVID-19 Prevention and Shared-Room Recovery After the 2026 Lak Si Flood

Back from a shelter or relatives

• Watch your household's symptoms for one to two weeks
• Test with ATK if anyone has fever, cough, sore throat or loss of smell
• Wash returned clothes, blankets and bags before storing
• Ventilate daily whenever it is not raining

If someone is infected

• Separate them from older adults, pregnant women and young children
• Mask when close; wash hands often; do not share cups, spoons or towels
• High-risk people contact a health service as soon as they test positive

After the water recedes and everyone recovers

• Wear rubber gloves, boots and a mask to clean the ground floor
• Wash mud and tide marks with clean water and detergent
• Wipe handles, switches, remotes and taps
• Discard soaked mattresses, rugs or sofas that smell musty or show mould
• Clean air-conditioner filters; dry rooms completely with open windows and fans

Ozone day and after

• Everyone, pets and plants out; food moved out of treatment zones
• Close doors and windows as advised; wait for full ventilation before returning
• Keep ventilating and ask a doctor about vaccination for high-risk family members

FAQ: COVID-19 After Floods and Ozone in Lak Si

What are COVID-19 symptoms now, and how do they differ from flu?

Fever, cough, sore throat, blocked nose, aches, fatigue and sometimes loss of smell. They overlap with flu and colds, so ATK testing helps, and a doctor should assess severe symptoms.

Should I do an ATK test after returning from a shelter?

If you have fever, cough, sore throat or loss of smell, yes, and keep away from high-risk family members meanwhile. Without symptoms, keep watching and wash hands often.

How does COVID-19 spread? Can I catch it from surfaces?

Mainly through respiratory particles, especially in closed, crowded rooms. Surface spread is less common, but handwashing and wiping shared touch points still help.

Is COVID-19 after a flood dangerous?

Most cases are mild, but older adults, people with chronic illness and pregnant women can become seriously ill. Contact a health service early and go to hospital for breathlessness or chest pain.

Does ozone eliminate the COVID-19 virus?

According to the company's certification, the service eliminates virus, bacteria and mould groups at 99.99%, but no SARS-CoV-2-specific test is listed on the service page. Ask WHD for the data. Ozone is not treatment and does not replace vaccination.

Is ozone dangerous? Can I stay at home during treatment?

Not in the room being treated. The space must be empty and ventilated for the time the technician sets before re-entry.

When should ozone be done? Can it be done while someone has COVID-19?

After recovery, after cleaning and drying, and when the room is empty. Nobody should stay in the room during treatment.

How do I remove a musty smell after a flood?

Discard soaked items, wash surfaces and fabrics, clean filters and dry the house. If odour remains, ozone in the empty room can help.

How much does ozone treatment cost?

It depends on area, rooms and condition. WHD quotes per job. Call 065-556-6294 or LINE @whd268.

Is there ozone service near me in Lak Si?

WHD is based in Bang Khae, Bangkok 10160, and serves Bangkok including Lak Si. Dates are confirmed by phone or LINE according to schedule and road conditions.

Talk to WHD About Shared-Room Ozone After the 2026 Lak Si Flood

Tell us which rooms the water reached, where the smell lingers and whether older or high-risk relatives live with you. The WHD team will help plan a safe recovery order and ozone schedule.

See the Ozone Service and Request a Quote

Phone 065-556-6294 · LINE @whd268 · worldhealthdisinfection@gmail.com

World Health Disinfection, Bang Khae, Bangkok 10160. Serving all of Bangkok; for other provinces, please ask by phone or LINE.

Related Links and References

• Residential ozone disinfection service
• Disinfection spraying service
• WHD certificates
• Thai PBS: Ngamwongwan and Chaeng Watthana water levels, 26 Sep 2026
• Thai PBS: flooding near Thung Song Hong police station
• Thai PBS: Vibhavadi in front of Thai PBS, 27 Sep 2026
• Government PR Department: DDPM report as of 7 Oct 2026
• WHO fact sheets (COVID-19)
• CDC: Floods and your health
• Department of Disease Control, Thailand

This article is general information, not medical diagnosis or treatment. See a doctor if you feel unwell. Flood details reflect the dates of news and DDPM reports and change daily.