Last updated: 8 Oct 2026 | 5 Views |
If you are searching for "why do I get a headache every time I am inside after the flood", "dizzy because of the musty smell at home" or "is the musty smell after a flood dangerous", this guide is for you. Headache, dizziness, a foggy head, nausea and fatigue in a musty post-flood home can have several causes: odour compounds released by mold growing in walls and furniture, foul gases from bacteria in drains and mud, infections picked up while wading, and dehydration after diarrhoea. We explain them through the flood at Ban Mai Thai Thawon, Thap Rat subdistrict, Ta Phraya district, Sa Kaeo province in 2026 (B.E. 2569), go through the culprits one by one, list the warning signs that need a hospital right away, and explain why, after the house is washed and dried, the disinfection spraying service from World Health Disinfection (WHD) is a sensible final step to reduce germs on household surfaces.
Note: this is an example case based on situations commonly seen after floods. It is not the account of any specific person.
Somphong, in his sixties, lives in a single-storey house with his wife in Ban Mai Thai Thawon, Thap Rat, not far from Highway 348. During the Ta Phraya flood of 2026 (B.E. 2569), water from the Huai Lam Sathon stream spilled into the area, and the couple, his wife having a chronic illness, stayed at a temporary shelter for several days.
Back home, sticky mud still clung to the concrete floor, a tide line stained the lower walls, and the wooden TV cabinet had swollen. The bedroom smelled like wet laundry that never saw sunlight, and the bathroom drain gave off a rotten-egg smell. Worried about road dust, Somphong kept the doors and windows shut, and he set a small generator under the back eaves because power had not fully returned.
A few days later he woke with a dull headache and felt dizzy when standing up. His wife felt nauseous and heavy-headed. Yet when they sat outside or went to the market, they felt better. Their daughter, hearing this by phone, told them to move the generator far from the house and open every window at once: when several people in one home get headaches that improve outdoors, carbon monoxide must be considered first. Only then should mold and musty smells be tackled. Headaches in a flooded home can have overlapping causes, and some are more urgent than they look.
According to the Government Public Relations Department on 26 September 2026 (B.E. 2569), water from the Huai Lam Sathon stream, which rises in Ta Phraya National Park, overflowed onto Highway 348 at Ban Mai Thai Thawon, Thap Rat subdistrict, Ta Phraya district, Sa Kaeo. The water was about 30 cm deep over a stretch of about 200 metres, making it hard for small vehicles to pass.
Border Patrol Police Company 124 helped move older adults and patients to a temporary shelter. That means vulnerable residents were away from home for a while, and on return found houses that had been closed up, damp and full of leftover mud.
Nationally, the Department of Disaster Prevention and Mitigation reported at 06.00 on 7 October 2026 (B.E. 2569) that floods had affected 27 provinces plus Bangkok, 123 districts, 984 subdistricts and 1,154,875 households, or more than 3.1 million people. Many homes are now in recovery, when musty smells, mold and indoor discomfort become obvious.
Floods from forest streams like the one in Ta Phraya in 2026 carry a lot of mud, soil, leaves and organic matter. Left inside a closed house, this material is broken down by microbes that release odours, the source of the musty, earthy and rotten smells many families notice after the water goes down.
Before blaming mold, rule out the acute dangers. After floods many homes run generators, fuel-powered pumps or charcoal stoves. Placed indoors, in a garage or near doors and windows, they can fill a house with carbon monoxide, a gas with no colour or smell. Early symptoms are headache, dizziness, nausea, weakness and confusion, very similar to what people blame on a musty smell.
Another quick cause of headache and stinging eyes is mixing cleaning products, for example bleach with acidic toilet cleaners or ammonia, which releases irritating gases. Use one product at a time, follow the label and keep the room ventilated.
Once gases and chemicals are ruled out, these are the germs linked to headache, dizziness or a foggy feeling after floods, either through odours and compounds they release indoors or through infections where headache is a main symptom. This is general information, not a diagnosis.
Black mold grows on cellulose materials that stay wet, such as gypsum board, plywood and wall paper. Growing mold releases microbial volatile organic compounds (MVOCs), the source of musty odour. Many people living with heavy mold report headaches, irritated eyes and throat, and a foggy head. Research has not fully settled the mechanism, but public health agencies agree that moldy, musty homes should be fixed, not lived with.
Common on damp walls, dust and soaked materials, Aspergillus releases spores and musty compounds that irritate the airways and can bring on headaches and tiredness in sensitive people. In people with severely weakened immunity, its spores can cause lung infection, so they should stay away from moldy cleanup.
This blue-green mold grows on fabric, mattresses, the backs of cabinets and food spoiled in fridges during power cuts. It is a main source of the wet-laundry smell. Long hours in such rooms leave many people heavy-headed, congested and sleeping poorly, which can mean morning headaches.
Often found with black mold on long-wet gypsum board and paper, as grey-green or brown fuzz. It signals that a material has been wet long enough to be damaged. The musty odour it adds makes a home unpleasant and can trigger headaches in odour-sensitive people.
Trichoderma likes wood, particle-board cabinets and wooden floors that stayed wet, appearing as bright green patches. It breaks down wood and releases musty compounds, so swollen wooden furniture after the Ta Phraya flood of 2026 can be a major odour source.
Streptomyces are soil bacteria that produce geosmin, the familiar smell of earth after rain. When stream mud settles inside a house, they grow in damp walls and floors and give the home an earthy, musty smell. Odour-sensitive people may feel nauseous and get headaches, and heavy dried-mud dust also irritates the airways.
The rotten-egg smell from drains, septic tanks and stagnant mud comes from bacteria that break down organic matter without oxygen and release hydrogen sulfide. At low levels it causes headache, nausea, eye irritation and dizziness. In confined spaces such as septic tanks and underground pipes it can build up to seriously dangerous levels, so never climb into a tank or pipe yourself; call trained workers with proper equipment.
Leptospirosis must always be considered after wading in floodwater. The bacteria enter through cuts or skin soaked for a long time. Typical signs are sudden high fever, severe headache, muscle pain especially in the calves, and red eyes. A headache with fever after wading or mud cleanup is not just a musty-smell problem: see a doctor and mention the flood. Leptospira is not on the product's named list; it belongs to the bacteria group the product says it covers, and you can ask WHD for test data.
Flu brings headache, high fever, body aches, deep fatigue and dizziness. It spreads easily in shared shelters and can come home with returning families. According to WHD's service information, influenza H1N1 and H5N1 are on the list of covered organisms.
After floods, food and drinking water are easily contaminated. Norovirus causes sudden vomiting and diarrhoea; losing a lot of fluid leads to dehydration, with headache, dizziness on standing, a dry mouth and little urine. Norovirus lingers on surfaces and spreads very easily. According to WHD's product information, norovirus is on the covered list.
Legionella grows in warm stagnant water, such as storage tanks, unused pipes and some air-conditioning water systems. Breathing in water mist when taps are first used after a flood can cause a flu-like illness with fever, headache and aches, which in some people progresses to pneumonia. Run taps for a while and clean storage tanks before use. Legionella belongs to the bacteria group the product says it covers but is not on the named list.
Standing water breeds Aedes mosquitoes, which carry dengue virus, causing high fever, strong headache especially behind the eyes, and body aches. In rural and forest-edge areas like Ta Phraya, chiggers in tall grass can carry scrub typhus, with fever, headache and sometimes a black scab where the bite was. Neither spreads through household surfaces, so spraying is not the main protection. Remove standing water, cover up in tall grass, and see a doctor for fever.
See a doctor right away, or call 1669, if:
This is general information, not a diagnosis or medication advice. Do not keep taking medicine on your own to mask a headache, as it can hide an illness that needs urgent care.
Why does the smell persist after scrubbing? Mold and bacteria hide where water soaked deep: inside walls above the tide line, under wooden floors, beneath kitchen cabinets and in drains. Pouring bleach on surfaces does not reach soaked materials, and painting over mold lets it return. Remove damaged materials, clean, dry fully, then disinfect what remains, the clean-then-disinfect approach WHO and CDC recommend. For musty air that lingers after the source is gone, residential ozone disinfection can be a complementary service, done in an empty, closed space with people, pets and plants out.
The WHD disinfection spraying service uses trained technicians who spray and/or ULV-fog (Ultra Low Volume fine mist). According to the service information, the disinfectant is CHEMGENE HLD4H, a medical-grade product from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride.
According to WHD's service and product information, the organisms it is stated to cover include SARS-CoV-2 (COVID-19), human coronavirus 229E, RSV, influenza H1N1 and H5N1, hand-foot-and-mouth virus, norovirus, Salmonella, Bordetella pertussis, mycobacteria, and bacteria and fungi in general. The service page states 99.99%, and the product page states 99.85% against COVID-19 within 1 minute. The site lists approvals and references from the Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019.
Black mold, Aspergillus, Penicillium, Chaetomium, Trichoderma, Streptomyces, Leptospira, Legionella and drain bacteria are not on the named list, so we make no organism-specific claims. They belong to the fungi and bacteria groups the product says it covers, and WHD can be asked for specific test data.
Spraying reduces germs on surfaces after cleaning. It does not treat headaches or any illness, does not solve carbon monoxide, and does not replace removing moldy materials. Anyone with symptoms should see a doctor.
WHD is based in Bang Khae, Bangkok 10160, and serves upcountry areas by appointment via phone or LINE. It has no local branch, and dates depend on the schedule, so same-day service cannot be promised. According to the service information, the promotion includes a free CHEMGENE spray bottle and WELLGIENIC wet tissues, and tax invoices are available.
This is an example to explain the process. Real results depend on the house and how well odour sources are removed. If headaches continue in a clean home, see a doctor to look for other causes.
Possible causes include mold odours, drain and mud gases, dehydration or infection. If several people are affected and improve outdoors, suspect carbon monoxide from engines first.
It signals mold or bacterial growth and can bring headaches, irritation and allergy flare-ups. Find the source, remove damaged items and dry the house.
Many people in heavily moldy homes report headaches, irritated eyes and a foggy head. Health agencies advise removing mold and moisture, though the mechanism is still studied.
Leptospirosis, flu, dengue or another infection. See a doctor and mention the flood.
Sudden severe pain, stiff neck, confusion, one-sided weakness, high fever, heavy vomiting, dehydration, or several people affected at once. Go to hospital or call 1669.
Ventilate, refill dry drain traps, wash mud from gutters and have the septic tank inspected. Never enter a tank or pipe yourself.
Not recommended. It does not remove the cause and mixed scents can worsen headaches.
No. It reduces surface germs after cleaning but does not treat headaches or remove engine gases. See a doctor for symptoms.
Yes. Leave the sprayed zone and return when technicians advise, generally about 30 minutes according to the service information.
WHD is based in Bang Khae, Bangkok, and serves Sa Kaeo by appointment via 065-556-6294 or LINE @whd268. No local branch; dates depend on the schedule.
After damaged items are removed and the house is washed and dried, book technicians to reduce germs on surfaces before older adults and patients move back in.
See the Disinfection Spraying Service
Call 065-556-6294 | LINE: @whd268
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