The 2026 Chatuchak flood: what the news reported

According to Thai PBS, the highest rainfall recorded in Bangkok over 25 to 26 September 2026 was in Chatuchak District, at 210.0 millimetres (source: thaipbs.or.th/news/content/558661).

Another Thai PBS report said that on 26 September 2026 floodwater stood at 15.8 cm on Thetsaban Songkhro Road, 12.6 cm on Ratchadaphisek Road and 11.5 cm on Ngamwongwan Road (source: thaipbs.or.th/news/content/558585). Naewna reported that at 18:30 on 25 September 2026 there was a waterlogged stretch of Phahonyothin Road between BTS Kasetsart University station and the Royal Forest Department, in front of Kasetsart University (source: naewna.com/n/bkk/81721).

City-wide, reports described more than 300 mm of rain in about 48 hours and all 50 districts declared disaster zones on 26 September 2026; on 6 October the Department of Disaster Prevention and Mitigation put affected Bangkok households at 329,000. These are not Chatuchak-only figures, and levels change hourly, so follow the latest BMA updates.

Flood spots in Chatuchak and nearby areas worth checking

To keep things clear, we separate the spots that were actually reported from the places we suggest you inspect.

• Phahonyothin Road, BTS Kasetsart University to the Royal Forest Department, in front of Kasetsart University: reported as a waterlogged point at 18:30 on 25 September 2026 (Naewna).
• Thetsaban Songkhro Road: 15.8 cm on 26 September 2026 (Thai PBS).
• Ratchadaphisek Road: 12.6 cm on 26 September 2026.
• Ngamwongwan Road: 11.5 cm on 26 September 2026.

Ten-odd centimetres sounds minor, but urban floodwater is rarely clean rain: when drains overflow, water carrying grease, rubbish and sewage pushes up through grates and spreads across pavements, car parks, lobbies and shophouse ground floors.

No depths were reported for them, but we suggest inspecting side sois, street-level dorm floors, car parks, pavement restaurants and stalls, storerooms and station walkways, where many people pass daily.

A typical scenario: a ground-floor rental room near BTS Kasetsart that will not stop smelling

(An illustrative scenario, not a real person.)

Mint, a third-year student, rents a ground-floor room in a small dormitory down a soi in the Kaset area. On the evening of the downpour she walks from the train station along a pavement covered in ankle-deep water, her canvas shoes soaked. At the dorm she finds that water from the gutter outside has run along the corridor and crept under her door into half of her room.

She mops and runs a fan. Days later the room smells like a drain, black dots appear on her wardrobe, her toes itch, and a neighbour has diarrhoea after using the shared kitchen. Mopping and fans do not reach germs in grout, wall edges and shared touch points, so we rank what to tackle first.

How we built the post-flood germ ranking for Chatuchak (an editorial ranking)

Please note that this is WHD's editorial ranking. It is not an official public-health ranking and it is not based on patient data from Chatuchak. We do not have district-level infection figures and we will not invent any. The order combines these criteria:

1. Link to floods in WHO, CDC and Department of Disease Control guidance.
2. Fit with the flood type: urban waterlogging with drain backflow, so sewage and indoor-damp germs weigh more.
3. Severity of illness.
4. Local risk groups: students, commuters, vendors, older people and young children.
5. Persistence and spread, described qualitatively.

It prioritises cleanup; it is not a diagnosis. Anyone unwell after floodwater contact should see a doctor.

Nine germs to watch after the Chatuchak flood, ranked for the Phahonyothin and Ngamwongwan area

No. 1: E. coli and sewage bacteria (Escherichia coli and other gut organisms)

Why it ranks first: Chatuchak's flooding was urban waterlogging, and that almost always includes water from the drains. In an area packed with restaurants, dormitories and shophouses, drains carry kitchen waste, dishwater and in places overflow from septic or holding tanks. E. coli is the standard indicator of faecal contamination; where sewage gets into a building, assume other gut germs came along too.

Where it hides: ground-floor tiles and grout, door sills, under shoe cabinets, car parks, trolley wheels, shared dorm kitchens, gutters outside restaurants and soaked doormats.

Symptoms and risk groups: diarrhoea, stomach cramps, nausea and vomiting; some strains cause bloody diarrhoea. Young children, older adults, pregnant women and people with weak immunity are more prone to dehydration.

Prevention: wash hands with soap after touching floodwater or wet items, throw away food that was in the water, rinse dishes in clean water before use, and wear gloves and boots while cleaning.

How cleaning and spraying help: remove mud and wash with water and detergent first, because dirt weakens every disinfectant, then spray the surfaces. According to the product information, CHEMGENE HLD4H covers bacteria broadly. We do not claim a tested result for E. coli specifically, as the website does not list one; you can ask WHD for the test documents for this organism.

No. 2: Leptospira, the cause of leptospirosis

Why it ranks second: neighbourhoods full of food businesses and rubbish attract rats living in the drains. When water pools, rat urine mixes in. Leptospira enters through cuts, scrapes, the eyes, nose and mouth, and skin softened by long soaking. People who wade from train stations or bus stops every day are more exposed than they think. Thailand's Department of Disease Control warns about leptospirosis after every flood, so it stays near the top even though the water in Chatuchak was not deep.

Where it hides: thin mud along kerbs, ground-floor storerooms, the back of restaurants, bin areas and wet cardboard boxes.

Symptoms and risk groups: sudden high fever, headache, muscle pain especially in the calves and thighs, and red eyes, often several days after exposure. People who wade without boots, vendors, cleaners and anyone with foot wounds are most at risk. Fever with calf pain after wading means see a doctor straight away.

Prevention: avoid wading; if you must, wear boots, cover wounds with waterproof plasters, and wash and dry your feet when you arrive. Keep rubbish and food waste in lidded bins.

How cleaning and spraying help: wash away mud first, then spray flooded surfaces. Leptospira is a bacterium, within the group the product says it covers, but no organism-specific result is listed on the website; ask WHD for details. Rodent control must run alongside.

No. 3: Mold in rooms, condos and offices (Aspergillus, Penicillium, Cladosporium, Stachybotrys)

Why it ranks third: city buildings are often sealed, air-conditioned and short on windows. When floors, lower walls, ground-floor ceilings or wall linings get wet and dry slowly, mold starts to grow. WHO and CDC advise cleaning and drying within 24 to 48 hours to limit mold, but in dorms or condos where owners are away or waiting for building management, that window often passes before anyone acts.

Where it hides: the bottom of gypsum walls, particle-board cabinets, bed bases, carpets, curtains, cardboard in storerooms, behind fridges and in rooms left closed with the air-con off for days.

Symptoms and risk groups: stuffy nose, sneezing, coughing, itchy eyes and rashes. People with allergies or asthma may flare up; people with weak immunity should not clean heavily molded rooms themselves.

Prevention: open windows, run a dehumidifier, remove absorbent materials that cannot be dried, and wear a mask and gloves while cleaning.

How cleaning and spraying help: deeply molded gypsum or swollen particle board may need replacing; no product fixes that. After removal and washing, spraying treats the remaining surfaces. The service information says fungi and mold are covered, and if a musty smell lingers in the air, ozone treatment can be added as a complementary service.

No. 4: Norovirus in dormitories and workplaces

Why it ranks fourth: norovirus spreads very easily via hands, surfaces and food. In places where people share bathrooms, kitchens, lifts and desks, like student dorms and offices along Ratchadaphisek, one sick person can quickly become several. Bathrooms and ground floors touched by sewage raise the odds further.

Where it hides: door handles, lift buttons, taps, flush buttons, shared kitchen tables and stair rails.

Symptoms and risk groups: sudden vomiting, diarrhoea, cramps and sometimes a mild fever. Most people recover in a few days, but small children and older adults can become dehydrated; use oral rehydration salts and see a doctor if things do not improve.

Prevention: wash with soap and water, since alcohol gel may not be enough for this virus; sick people should not cook for others until well; clean bathrooms right after a sick person uses them.

How cleaning and spraying help: norovirus is listed among the organisms CHEMGENE HLD4H covers, according to the product information, so spraying shared touch points after cleaning matches this risk directly.

No. 5: Skin fungi and Candida, the cause of "flood foot" (dermatophytes, Candida)

Why it ranks fifth: many people here walk from stations and bus stops through waterlogged pavements and then sit all day in wet shoes and socks. Skin that stays damp invites fungal and yeast infections. Less serious than the top ranks, but very common after floods.

Where it hides: damp shoes, doormats, shared shower rooms, shared towels and locker-room floors.

Symptoms and risk groups: itching between the toes, peeling, soggy red skin and odour. People with diabetes should take extra care because foot wounds heal slowly.

Prevention: wash and dry feet, especially between the toes, change socks often, dry shoes completely and do not share towels.

How cleaning and spraying help: spraying bathroom floors, corridors and shoe areas reduces fungi on surfaces; the product information says the fungi group is covered. Skin symptoms should go to a doctor or pharmacist.

No. 6: Respiratory viruses: influenza, RSV and COVID-19

Why it ranks sixth: these viruses do not come with floodwater, but during floods people crowd into closed spaces, wait longer for transport, squeeze onto trains or move in with friends, and tired, rain-soaked bodies may be more vulnerable. In an area with a university, offices and mass transit, respiratory germs belong on the list.

Where they hide: lift buttons, handrails, meeting tables, shared keyboards and lobby seating.

Symptoms and risk groups: fever, cough, sore throat, runny nose and fatigue; young children, older adults and people with chronic illness are at risk of severe illness.

Prevention: mask when sick or in crowds, wash hands often, ventilate rooms and get vaccinated as your doctor advises.

How cleaning and spraying help: the service information lists COVID-19, RSV, H1N1 and H5N1 as covered, so spraying common areas after a flood addresses these at the same time as sewage germs.

No. 7: Salmonella in roadside restaurant kitchens

Why it ranks seventh: Kaset, Ngamwongwan and Ratchadaphisek are full of restaurants, curry-and-rice shops and street stalls. When water reaches a kitchen or ingredient store, or the power cuts and fridges stop, food contamination and spoilage become more likely.

Where it hides: chopping boards, knives, prep tables, kitchen shelves, flooded fridges and ice bins.

Symptoms and risk groups: fever, diarrhoea, cramps and nausea; children, older adults and pregnant women need extra care.

Prevention: discard ingredients touched by floodwater or left unrefrigerated too long, wash utensils with clean water and dish soap, separate raw and cooked boards and cook food thoroughly.

How cleaning and spraying help: Salmonella is listed among covered organisms in the product information. In kitchens the technicians plan spray points with the owner, and food-contact surfaces should be rinsed with clean water before reuse, as the technicians advise.

No. 8: Staphylococcus and Streptococcus, the wound infection bacteria

Why it ranks eighth: while wading or moving belongings, many people cut themselves on glass, drain-cover edges or debris hidden in murky water. Wounds exposed to dirty water let skin and environmental bacteria cause infection. Wounds from dirty objects also carry a tetanus risk, so ask a doctor about tetanus vaccination.

Where they hide: shared cleaning tools, mops, rags, reused gloves and first-aid areas.

Symptoms and risk groups: a wound that is swollen, red, hot, painful or oozing, or a fever. People with diabetes and older adults should see a doctor promptly if a wound is not improving.

Prevention: wash wounds with clean water and soap, cover them with waterproof plasters and avoid wading with open wounds.

How cleaning and spraying help: both are bacteria within the group the product says it covers, but no organism-specific result is listed; ask WHD for documents. Spraying reduces germs in the environment; wound care must follow medical advice.

No. 9: Pseudomonas in places that never dry (Pseudomonas aeruginosa)

Why it ranks ninth: Pseudomonas likes still water and places that never dry: drains, air-con drip trays, water tanks. After urban flooding these spots collect extra silt and grime, forming a slimy layer called biofilm.

Where it hides: bathroom floor drains, air-con drip trays, ground-floor water tanks and rarely used sinks.

Symptoms and risk groups: most healthy people are rarely affected, but people with wounds, contact-lens wearers and those with weak immunity can get skin, ear or eye infections.

Prevention: scrub drains and drip trays, change stored water and dry areas quickly.

How cleaning and spraying help: scrub away the slime first, then spray around wet spots. Pseudomonas is in the bacteria group the product says it covers, with no specific result listed on the website; ask WHD for more.

Near misses

Rotavirus and hand, foot and mouth viruses matter greatly in homes with toddlers; if that is you, move them up level with norovirus (hand-foot-mouth virus is listed as covered). Hepatitis A depends more on food and drinking water than surfaces. Melioidosis fits muddy farmland floods, not paved city roads.

The post-flood germ ranking for Chatuchak at a glance

What happens when post-flood germs in Chatuchak are ignored

Recurring diarrhoea, rashes or allergy flare-ups in the same dorm or office mean the source is still there. Students miss classes, colleagues fall ill in turn, untreated mold spreads until walls and mattresses must be replaced, and restaurants or condos with musty smells lose customers. In shophouses where grandparents and children live together, the most vulnerable are hit first.

Why soap, floor cleaner or bleach alone may fall short

Detergent removes dirt but is not made to disinfect. Scented cleaners mask the musty smell that signals damp. Diluted bleach works but irritates in small rooms, corrodes some metals and must never be mixed with certain cleaners, and hand wiping misses corners and car parks. WHO and CDC advise: remove mud, wash, dry, then disinfect. Spraying fills that last step.

WHD post-flood disinfection spraying for Chatuchak dorms, condos, shops and offices

According to the service information, WHD's disinfection service is carried out by trained technicians using spraying and/or ULV (Ultra Low Volume) fine-mist fogging. The disinfectant is CHEMGENE HLD4H, a medical-grade product from the UK containing Benzalkonium Chloride and Didecyldimethylammonium Chloride. The page lists viruses, bacteria and fungi including COVID-19, RSV, H1N1, H5N1 and hand-foot-mouth virus, claims 99.99%, and names the Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019. Customers include hospitals, schools, malls, airports, offices, airlines, banks and residential buildings; the promotion adds a free CHEMGENE spray bottle and WELLGIENIC wet tissues, and tax invoices are available.

WHD is based in Bang Khae, Bangkok 10160, with no branch in Chatuchak. Bookings go through 065-556-6294 or LINE @whd268, and the team confirms dates based on the real queue; after floods it can be busy, so same-day service cannot be promised.

Five steps for city buildings

1. Survey: send photos or video on LINE with room count, flood height and smelly or moldy spots.
2. Mud removal and washing: done first by the owner or cleaners; spraying never replaces washing.
3. Zoning: cover food and personal items; people and pets leave the zone being sprayed.
4. Spraying: spray and/or ULV by zone, focusing on floors, lower walls, sills, touch points, bathrooms and kitchens.
5. Re-entry: the service information says wait about 30 minutes, but always follow the re-entry time the technicians give for your job.

We do not claim spraying leaves no residue; rinse food-contact surfaces and children's toys with clean water as advised. Anyone who is ill should see a doctor; spraying treats spaces, not people.

10 reasons to choose WHD after the Chatuchak flood

1. A clear order: wash first, spray second, in line with WHO and CDC.
2. Medical-grade CHEMGENE HLD4H, stated to cover viruses, bacteria and fungi broadly.
3. ULV mist reaches corners and wide areas like car parks better than hand wiping.
4. About 30 minutes before reuse, per the service information, which suits dorms and shops.
5. Experience with hospitals, schools, offices and residential buildings.
6. Reference to EN 14476:2013+A2:2019 and the bodies named on the page.
7. Spray plans follow this ranking: shared bathrooms, kitchens and ground floors first.
8. You can ask for test documents for any organism you worry about.
9. Tax invoices for condo juristic persons and companies.
10. Easy contact by phone 065-556-6294 or LINE @whd268, with the listed promotion.

Before and after spraying a ground-floor dorm

Example case: a Ngamwongwan curry shop working through the nine ranks

(An illustrative example, not a customer review.)

Toy runs a curry shop off Ngamwongwan; gutter water reached her kitchen. She binned doubtful ingredients (rank 7), washed floors with detergent (rank 1), set rat traps and wore boots (rank 2), dried everything (rank 3), then booked WHD on LINE. Staff left during spraying and she waited the given time before rinsing prep tables and reopening.

Recovery checklist

Before spraying: photograph damage for insurance or relief claims; keep power off in flooded areas until checked; wear gloves, boots and a mask; discard flooded food, medicine and cosmetics; remove mud and wash; strip swollen carpet and gypsum; ventilate and dry.

After spraying: re-enter when the technicians say; rinse food-contact surfaces and toys; watch for new mold for two to three weeks; wash hands often and keep towels separate; see a doctor for fever, calf pain, diarrhoea or infected wounds, and mention the flood.

FAQ

The water was only about 10 to 15 cm. Do I really need spraying?
Depth is not the only measure. Urban floodwater usually contains drain water, so if it entered kitchens, bathrooms or rooms used by children or older people, clean then disinfect. Technicians can help decide which zones.

Is this an official ranking?
No. It is WHD's editorial ranking using the criteria above, not patient data.

Can a condo's management book only common areas?
Yes, such as car parks, lobbies, bin rooms and ground-floor corridors; individual units can book separately.

Does WHD have a Chatuchak branch?
No. WHD is in Bang Khae; call 065-556-6294 or LINE @whd268 for available dates.

Does the disinfectant work on E. coli or Leptospira?
Both are bacteria within the group the product says it covers, but no specific results are listed on the site; ask to see the documents.

Cleaned up? Let WHD finish the job in Chatuchak

Book post-flood disinfection spraying

Phone 065-556-6294 | LINE @whd268

Related services and references

• WHD disinfection spraying service
• Residential ozone disinfection for musty smells
• Thai PBS rainfall: 558661; road levels: 558585; Naewna: 81721
• WHO fact sheets, CDC Floods, Department of Disease Control