Example case (a typical scenario based on common real-world situations, used for illustration; it is not a review from a specific customer)

The morning the water went down, the dorm still smelled of drains

Sunee owns a four-storey student dormitory in a narrow lane off Phahonyothin Road, across from Kasetsart University. The ground floor holds a small lobby, a coin-operated laundry room and a chicken-rice stall rented to a relative. During the downpour of 24 to 27 September, water on Phahonyothin at the mouth of her lane rose high enough that sedans were inching through it one by one. Water from the roadside drains backed up into the lane, rolled over the door sill into the lobby and mixed with runoff from the drainage channel behind the food stall.

Many students had to wade home from the BTS station. Some wore flip-flops; a few walked barefoot after losing a sandal in the current. When the water receded two or three days later, Sunee and her housekeeper shovelled the mud out, hosed down the lobby floor, wiped the food counter with ordinary floor cleaner and propped every door open to let the breeze through. On the surface, everything looked normal again.

Within a week, two students had diarrhoea and another had a foot scrape that turned red and swollen. The laundry room smelled permanently of damp clothes left overnight, and a line of small black spots began to appear along the bottom of the plastered wall. The relative running the chicken-rice stall worried that customers would not return, because everyone in the lane knew the water that had flooded the shopfront was water that had passed through the drains of the entire road.

Sunee called a disinfection provider with the question many owners along Phahonyothin ask: "I've already washed everything. Do I still need to spray?" First, let us look at exactly where the water was.

Where Phahonyothin Flooded: Kasetsart to the Royal Forest Department and Bang Khen Circle to Ro 11

The points below come from a Thai PBS report published on 29 September 2026 at about 13:19, which drew on Bangkok Metropolitan Administration (BMA) flood data. Depths are the water level on the road surface at the time of reporting, not the peak of the whole event.

• Phahonyothin Road near Kasetsart University: about 10 cm (per news report, 29 Sep 2026)
• Phahonyothin Road, Kasetsart University to the Royal Forest Department: listed as a flood point
• Phahonyothin Road, Bang Khen Circle to the 11th Infantry Regiment (Ro 11): listed as a flood point
• Phahonyothin Road at Ro 11 Gate 2: about 20 cm
• Phahonyothin Road near Soi Phahonyothin 60/1: about 22.8 cm, one of the deepest readings on the list at that time

Connecting roads in the same part of the city were also reported under water:

• Ram Inthra Road, Bang Khen Circle to Lat Pla Khao station: flood point; Dailynews also reported high water at Ram Inthra Soi 23 and Soi 24
• Thepharak Road at Big C Saphan Mai: about 20 cm; Thepharak Road from Phahonyothin to Khlong Bang Khen: flood point
• Vibhavadi Rangsit Road, outbound, at the Kamphaeng Phet 6 junction: about 20 cm
• Songprapha Road, Vibhavadi to Khlong Prem Prachakon: flood point
• Ngamwongwan Road near Soi Chinnakhet and near Khlong Prem prison: flood point
• Chaeng Watthana Road near Phranakhon Rajabhat University: about 15 cm
• Chang Akat Uthit Road, Soi 15: about 5 cm

The bigger picture: roughly 300 mm of rain fell in about 48 hours between 24 and 27 September 2026. On 26 September the BMA declared all 50 districts a disaster zone, and as of 2 October 2026 the Department of Disaster Prevention and Mitigation put the number of affected Bangkok households at about 329,000. Upper Phahonyothin runs through Chatuchak and Bang Khen districts and is lined with a university, government offices, a military base, dormitories, shophouses and food outlets, so many people waded and carried germs indoors.

The Germs That Follow a Flood on Phahonyothin, and Why a University District Needs Extra Care

Urban floodwater is not clean rainwater. Water flowing along Phahonyothin has passed through gutters, manholes, rubbish bins and restaurant drains, and sometimes mixes with overflow from septic tanks. When it drains away, it leaves a thin film of mud on floors, lower walls, table legs and furniture, and that film can carry many kinds of microorganisms. The World Health Organization, the US Centers for Disease Control and Prevention and Thailand's Department of Disease Control all warn that waterborne infections, gastrointestinal illness, skin infections and mould tend to rise after floods.

1. E. coli and faecal bacteria

Bacteria from human and animal intestines, such as E. coli, are a marker of sewage contamination. When drains overflow, sewage is spread everywhere. Dried residue on counters, stair rails and door handles can pass bacteria to hands and then to mouths. Typical symptoms are diarrhoea, stomach cramps, nausea and sometimes fever. In a stretch packed with restaurants and street stalls, like the area opposite Kasetsart University, this is the first risk to tackle.

2. Leptospirosis

Leptospira bacteria are shed in the urine of rats and some other animals. During a flood, rats move to higher ground and closer to people, while the water spreads the bacteria widely. The infection enters through cuts, scrapes or the membranes of the eyes, nose and mouth, especially after long exposure to water. Hallmark symptoms are a sudden high fever, headache and severe muscle pain, particularly in the calves. Thailand's Department of Disease Control stresses that anyone who develops a fever within about two weeks of wading through floodwater should see a doctor and mention the exposure, rather than self-medicating. That advice matters for students and office workers who waded from bus stops and BTS stations around Bang Khen.

3. Salmonella and food poisoning bacteria

Flooded restaurants, canteens and dorm kitchens are prone to cross-contamination between floors, utensils, chopping boards and fresh food. Salmonella causes food poisoning with diarrhoea, fever and abdominal cramps. If fridges or display chillers lost power during the flood, stored food may also have spoiled. Anything that touched floodwater should be thrown away.

4. Norovirus and rotavirus

These two viruses are leading causes of acute diarrhoea. They spread easily via contaminated surfaces and can persist on them for a long time. In buildings where many people share space, such as dormitories, offices or classrooms, one sick person can lead to a cluster of cases within days. Rotavirus mainly affects young children, while norovirus can cause violent vomiting at any age.

5. Hand, foot and mouth disease and RSV in children

Upper Phahonyothin has family homes, daycare centres and schools tucked into its side lanes. The post-flood period coincides with the rainy season, when RSV and hand, foot and mouth disease already circulate among children. When children are crowded together during a flood, or play with toys that touched the water, the risk goes up. WHD's service information lists these viruses among those its disinfectant covers, as explained in the service section below.

6. Mould and musty odour

Plaster walls, wooden door frames, gypsum ceilings, carpets and upholstery that soaked up water can start growing mould within a day or two if they stay damp. The CDC recommends cleaning and drying within 24 to 48 hours to limit mould. Spores can trigger allergies and asthma and are hard on older people. A musty smell is a sign that moisture and microbial activity are still present in materials.

Who is most at risk

Young children, older adults, pregnant women and people with chronic conditions such as diabetes, kidney disease or weakened immunity are more likely to become seriously ill. In this neighbourhood, the people with the most exposure are students who waded home, delivery riders, street vendors, security guards and cleaners who shovelled out the mud.

What Building Owners on Phahonyothin Typically Face After the Water Drains

Health: Tenants or staff fall ill in waves, with diarrhoea, rashes, infected cuts and allergy flare-ups. If cleaning was not thorough, people who recovered can be re-exposed to surfaces that are still contaminated.

Money: A dormitory with a musty smell and rumours of sick tenants can lose occupants at the start of term. A restaurant loses sales when diners lose confidence. An office deals with sick leave and may need to replace mouldy furniture sooner than planned.

Time: Repeated cleaning without a clear process eats up days, and many shops stay closed longer than necessary out of uncertainty.

Reputation: In a district where most customers are students and young professionals who review everything online, a single post saying "smells like sewage" or "got sick after eating here" can hurt business for months.

Family: For families in the lanes around Bang Khen, worrying about a toddler or elderly parent in a house that was just under water is a daily strain.

Why the Usual Fixes Fall Short

Washing with water or floor cleaner only: Household floor cleaners are designed to lift dirt and leave a pleasant smell, not to disinfect sewage contamination. Mopping removes mud, but corners, wall edges and the space under furniture are usually missed.

Spot-treating with bleach: Diluted correctly, bleach works on some hard surfaces, but it has a harsh smell, corrodes metal and damages fabrics. Mixed wrongly, or with other cleaners, it can release dangerous gases. As a result, most people only use it on floors, not across the whole room.

Running fans and calling it done: Fans help dry surfaces, but they do not kill germs, and they can blow mould spores around the room.

Air freshener: A nice scent makes a room feel clean, but the cause of the odour remains. When the fragrance fades, the musty smell returns.

Painting over mould straight away: If the wall is still damp, mould will keep growing under the paint and make it bubble or peel within weeks. Walls need to dry completely before repair.

Cleaning must always come first, but for high-traffic dorms, restaurants and offices, professional spraying fills the gaps hand cleaning misses.

WHD Disinfection Spraying on Phahonyothin: How It Works

World Health Disinfection provides a disinfection spraying service for all types of buildings. According to the service information, trained technicians spray and/or ULV-fog (Ultra Low Volume, a very fine mist) so the disinfectant reaches surfaces and corners more evenly than wiping by hand.

The disinfectant is CHEMGENE HLD4H, a medical-grade disinfectant from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride. According to the service information, it covers viruses, bacteria and fungi; the service page lists organisms including COVID-19, RSV, H1N1, H5N1 and the hand, foot and mouth virus, with a stated effectiveness of 99.99%.

The service page also lists approvals and endorsements from the Department of Medical Sciences (Thailand), Mahidol University, NHS England and the EN 14476:2013+A2:2019 standard. Customers include hospitals, schools, shopping malls, airports, offices, airlines, banks and residential buildings, which covers most of the building types found along Phahonyothin.

The process

1. Book: Call 065-556-6294 or message LINE @whd268 with your location (which soi off Phahonyothin), approximate floor area, number of floors and how high the water reached.
2. Prepare the area: Remove mud, wash dirty floors and walls, throw away mouldy or water-ruined items, and put away food, dishes and personal belongings.
3. Technicians spray: The team sprays or ULV-fogs the agreed areas. Occupants, staff and pets should leave the zone being treated.
4. Wait about 30 minutes: According to the service information, allow about 30 minutes after spraying, and follow the re-entry time the technicians give for your particular site.
5. Use the space normally: Reopen the dorm, shop or office as advised by the technicians.

Current promotion according to the service information: a free CHEMGENE spray bottle and WELLGIENIC wet tissues with the service, and a tax invoice is available, which suits companies, agencies and condominium juristic persons in the area.

To be clear: disinfection spraying comes after mud removal and washing. It does not replace cleaning, does not dry out damp walls, and is not medical treatment; anyone who is ill should see a doctor. We do not claim the disinfectant leaves no residue, so people should stay out during application and return only when the technicians say so. For rooms where a musty smell lingers in the air, the residential ozone disinfection service can be a useful add-on.

10 Reasons Buildings on Phahonyothin Should Be Disinfected After the Flood

1. The floodwater came from the drains of the whole road, from Kasetsart University to Ro 11, not just rain off the roof.
2. Large numbers of people waded in and out, including students, staff and riders, carrying germs from the street into lobbies and corridors.
3. ULV fog reaches corners a mop cannot, such as under counters, behind cabinets and along stair edges. See the disinfection service page for details.
4. A medical-grade disinfectant, CHEMGENE HLD4H, from the UK, used in hospitals and public facilities.
5. Covers viruses, bacteria and fungi according to the service information, including childhood viruses such as RSV and hand, foot and mouth.
6. Back in use after about 30 minutes according to the service information, ideal for restaurants and offices that need to reopen quickly.
7. Backed by documented references including the Department of Medical Sciences, Mahidol University, NHS England and EN 14476; check the certification page.
8. Tax invoice available for agencies, companies and juristic persons in Chatuchak and Bang Khen.
9. Restores tenant and customer confidence: dorm and restaurant owners can say the space was professionally disinfected.
10. Free supplies for follow-up care: a CHEMGENE spray and WELLGIENIC wet tissues for high-touch points after the visit. Learn more about WHD disinfection spraying.

Before and After Spraying: What Building Owners in Bang Khen Can Expect

Results depend on preparation, how dry materials are and ongoing care. Spraying does not dry damp walls, and it does not remove mould that has grown deep into materials, which should be removed.

Example Case: A Small Office Near Bang Khen Circle and the Chicken-Rice Stall Below the Dorm

Example case: a typical scenario, not a verified customer review.

Ek's accounting office occupies a three-storey shophouse on Phahonyothin between Bang Khen Circle and Ro 11. Water entered the ground floor, where the client reception and file storage room are. Six staff carried out wet folders, wiped desks and washed the floor. Two days after reopening, one employee began sneezing and feeling congested whenever she worked downstairs, and another was anxious because he has a two-year-old at home. Ek booked a spraying team for after office hours. The technicians advised throwing away a small rug that had soaked up water and removing damp cardboard boxes first. They then treated the entire ground floor, the stairwell and the toilet. Staff stayed out of the building during application and came back at the time the technicians gave. The office opened as usual the next morning. Ek kept running a dehumidifier for several more days because the lower walls were still not fully dry.

The chicken-rice stall from the opening story threw out its wooden chopping boards, sponges and all ingredients that had touched water, then washed the floor and walls with detergent before the team sprayed the stall, the lobby and the laundry room. The technicians advised storing food containers in a closed cabinet and rewashing any food-contact utensils after spraying. The stall reopened later the same day after the advised waiting time. The student with the infected foot was told to see a doctor right away and to mention that he had waded through floodwater.

In both cases, spraying was the final step of recovery, not the first.

Recovery Checklist for Buildings in the Phahonyothin and Bang Khen Area

Before spraying day

• Make sure the electrics are safe before going in. If sockets or the distribution board were submerged, have an electrician check them first.
• Wear rubber boots, gloves and a mask while removing mud, and cover any cuts.
• Remove all mud and debris; wash floors and lower walls with clean water and detergent.
• Throw away food, drinks and condiments that touched floodwater, plus wooden chopping boards and sponges.
• Discard or separate carpets, mattresses, cushions and cardboard boxes that were soaked.
• Open doors and windows and use fans and dehumidifiers to dry the space within 24 to 48 hours where possible.
• Photograph damage before cleaning, for insurance or relief claims.
• List the areas you want treated, such as lobby, storeroom, toilets and kitchen, and tell the technicians in advance.

During and after spraying

• Everyone, including pets, leaves the treatment zone and returns at the time the technicians advise.
• Store food and dishes in closed cupboards; rewash food-contact items after spraying.
• Ventilate once you are back inside.
• Wipe high-touch points such as handles, lift buttons and stair rails regularly with disinfectant.
• Keep monitoring moisture. If water stains or new mould appear, fix the cause before painting.
• Watch for symptoms. Anyone with fever, calf pain, severe diarrhoea or an infected wound should see a doctor.

FAQ: Post-Flood Disinfection Spraying on Phahonyothin

Q: I already washed the floor with floor cleaner. Do I still need disinfection spraying?
A: Washing removes mud and grime and must come first. But ordinary floor cleaners are not designed to disinfect sewage contamination, and hand wiping is rarely complete. For high-traffic buildings like dorms, restaurants and offices on Phahonyothin, spraying after washing reduces risk more thoroughly.

Q: Do we need to leave the building during spraying?
A: People and pets should leave the zone being treated. According to the service information, wait about 30 minutes after spraying, and follow the specific re-entry time the technicians give for your site.

Q: Which disinfectant do you use?
A: CHEMGENE HLD4H, a medical-grade disinfectant from the UK containing Benzalkonium Chloride and Didecyldimethylammonium Chloride. According to the service information, it covers viruses, bacteria and fungi.

Q: Will spraying make wall mould disappear for good?
A: Spraying treats microorganisms on surfaces, but if the wall is still damp or mould has grown into gypsum or wood, the moisture must be fixed and damaged material removed first, or the mould will come back.

Q: Can you treat a whole dormitory or multi-storey building?
A: Yes. According to the service information, customers include residential buildings, offices, schools and hospitals. Share the number of floors and approximate area so the team can assess the job.

Q: I waded through floodwater and now have a fever and calf pain. What should I do?
A: See a doctor immediately and mention that you waded through floodwater, as this may be leptospirosis. Disinfecting a building is not medical treatment.

Q: Can I get a tax invoice?
A: Yes. According to the service information, WHD can issue a tax invoice, which suits companies, agencies and juristic persons.

Book Post-Flood Disinfection Spraying in Phahonyothin and Bang Khen Today

Dormitories, restaurants, offices, clinics and homes around Kasetsart University, the Royal Forest Department, Bang Khen Circle and Ro 11 can talk to the WHD team now.

See the Disinfection Service and Book

Call 065-556-6294 · LINE @whd268

Related Links

• World Health Disinfection spraying service
• CHEMGENE HLD4H medical-grade disinfectant
• Residential ozone disinfection (add-on for musty air)
• Contact WHD

References

• Thai PBS, Bangkok flood points, 29 Sep 2026: thaipbs.or.th/news/content/558830
• Dailynews, Bangkok flooding, 29 Sep 2026: dailynews.co.th/news/6232155
• Post Today, Bangkok flood situation: posttoday.com/blogs/general-news/749418
• World Health Organization fact sheets: who.int/news-room/fact-sheets
• CDC, Floods: cdc.gov/floods
• Department of Disease Control, Thailand: ddc.moph.go.th