Before you read

• Place: Bang Na junction, outbound Bangna-Trat Road, Bang Na district, Bangkok.
• Reported fact: at 6:30 p.m. on 25 September 2026 the BMA reported a waterlogging point on a main road (source: Naewna). No water depth was given.
• This ranking is WHD's editorial view. It is not official, not statistical and not medical advice.
• Conditions change daily; check the latest BMA announcements.
• Fever, calf pain, diarrhoea or an inflamed wound after wading means you should see a doctor.

A typical scenario: a building manager the morning after the storm

Note: this is an example case based on situations often seen in office districts along major roads. It does not describe a real person or company.

Ton manages a mid-sized office building in the Bang Na area. On the evening of the heavy rain, messages kept arriving from tenants who could not get home. Water had pooled at the junction, buses were late and many people waded to reach them. Some gave up and walked back to the building to wait, trousers and shoes soaked. The lobby filled with wet footprints, dripping umbrellas lined the walls and the carpet in front of the lifts squelched underfoot.

The next morning the road was dry and traffic was back to normal, but the lobby smelled musty and the lift carpet had turned sour. The basement car park was streaked with silt and leaves carried in on tyres. One tenant said his car mats smelled strange after driving through the water. Another had a raw patch on his toe from wearing wet shoes all evening. The cleaner asked whether the usual floor cleaner would be enough.

Ton's situation is common around big Bangkok junctions. Road water may not stand for long, but the many people who touch it spread dirt and germs to many other places. Knowing which germs matter most helps plan cleaning at the building, at home and in the car.

Flood points at Bang Na junction: what was actually reported

• Bangna-Trat Road, Bang Na junction (outbound), Bang Na district: at 6:30 p.m. on 25 September 2026 the BMA reported a waterlogging point on a main road, according to Naewna. No depth or duration was given.
• Waterlogging points across Bangkok: 43 at 6:30 p.m. on 25 September (Naewna) and 135 on 27 September (Thai PBS).
• Rainfall: Thai PBS reported that rain on 25 and 26 September 2026 peaked at 210.0 mm in Chatuchak, 205.5 mm in Wang Thonglang and 203.5 mm in Saphan Sung, with more than 300 mm in about 48 hours. All 50 districts were declared disaster zones on 26 September.
• Aftermath: on 29 September the disaster status was lifted in 21 districts, leaving 29, and the Department of Disaster Prevention and Mitigation designated assistance zones in 38 districts and 118 subdistricts (Thai PBS). On 6 October the department reported about 329,000 Bangkok households affected (Bangkok Biz News).

We do not know how deep the water was at Bang Na junction, how long it stayed or which buildings it entered. The rest of this article therefore deals with surface waterlogging from heavy rain during rush hour and its effect on people passing through, rather than deep flooding inside buildings.

How we ranked post-flood germs for Bang Na junction

WHD's editorial team built this ranking to help building managers, car owners and families who use this route put tasks in order. The criteria:

1. Type of exposure: a big junction means short contact for very many people. Germs that enter through skin and wounds, or spread in crowded indoor spaces, weigh more.
2. Presence in post-flood health guidance: WHO, CDC and Thailand's Department of Disease Control.
3. Severity: germs that can cause serious illness if treatment is delayed rank higher.
4. How many people are affected: office workers, bus passengers, delivery riders and families collecting relatives.
5. Persistence in the environment: carpets, shoes and car interiors that dry slowly. Described qualitatively, with no unsourced numbers.

This order differs from rankings for restaurant streets or canal-side communities, because Bang Na junction is about travel, not riverside living.

Post-flood germs ranked at Bang Na junction: 8 for commuters, offices and cars

No. 1: Leptospira, the leptospirosis bacterium that enters through wounds

Why it ranks here: at a big junction many people wade through standing water to reach a bus or cross the road. Water pushed up from drains can contain urine from rats living in the drain system. Leptospira enters through cuts, grazes, skin softened by long soaking, and the lining of the eyes and mouth. The Department of Disease Control warns about leptospirosis every flood season and it can become serious if treated late, so it tops the list for a place where many people wade.

Where it hides: puddles along the pavement, gutters near bus stops, basement car parks where water flowed in, and shoes that have not dried.

Symptoms: sudden high fever, headache, muscle pain especially in the calves and red eyes, often within about one to two weeks of exposure. See a doctor and mention that you waded.

Prevention: avoid wading with open wounds or cover them with waterproof plasters, wash feet and legs with soap on arrival, and keep wading shoes apart and wash them before bringing them indoors.

Cleaning and spraying: in buildings, wash lobby floors, car parks and corridors with wet footprints first, then spray. CHEMGENE HLD4H product information does not name Leptospira; it belongs to the bacteria group the product states it covers, and you can ask for test data. Spraying is not treatment and does not replace seeing a doctor.

No. 2: Gut bacteria from wastewater, E. coli and Shigella

Why it ranks here: water forced up from drains can contain building wastewater. Gut bacteria ride on shoes and tyres onto lobby floors, lift floors and car mats. Hands that touch these surfaces and then the mouth can cause illness. Shigella needs only a small dose, so offices with shared toilets and kitchens should take care.

Where it hides: doormats, lift floors and buttons, handrails, toilet door handles and car floor mats.

Symptoms: diarrhoea, cramps, nausea and fever, sometimes with blood or mucus. Heavy diarrhoea, weakness or blood in stools needs a doctor.

Prevention: wash hands with soap before eating, do not put bags or food on uncleaned floors, and replace wet doormats.

Cleaning and spraying: wash or replace doormats, clean floors with detergent, then spray floors and shared touchpoints. The product information states coverage of bacteria in general but does not name E. coli or Shigella individually. Test data can be requested.

No. 3: Wound infection bacteria, Staphylococcus aureus and Streptococcus

Why it ranks here: people rushing through water at rush hour cannot see the ground. Broken glass, kerbs and open drain covers cause injuries, and shoes worn wet all day soften the skin and rub it raw. These wounds let bacteria in. Wounds contaminated with soil or rust also raise tetanus concerns, so ask a doctor about vaccination where appropriate.

Where it hides: bath mats in office washrooms, shared towels and spare shoes stored in damp lockers.

Symptoms: swelling, redness, heat, growing pain, pus or fever. People with diabetes should watch foot wounds closely.

Prevention: rinse wounds with clean water, keep them dry, switch to dry shoes quickly and never share towels.

Cleaning and spraying: spraying lowers bacteria on shared surfaces but does not treat wounds. Neither organism is named in the product information; both belong to the bacteria group the product states it covers.

No. 4: Respiratory viruses in crowded indoor spaces, influenza H1N1, RSV and SARS-CoV-2

Why it ranks here: these viruses do not come from floodwater. But on a stormy evening with water on the roads, crowds shelter together in lobbies, convenience stores and buses. Wet, tired people spend hours in air-conditioned rooms, which helps respiratory viruses pass between them. WHO notes that crowding after disasters raises the risk of respiratory infections, so this group ranks here for an office district.

Where it hides: lift buttons, bus grab rails, meeting tables, shared keyboards and water dispensers.

Symptoms: fever, cough, sore throat, runny nose and aches. Young children, older adults and people with chronic illness infected by someone at home may be hit harder. Difficulty breathing or a high fever that will not come down needs a doctor.

Prevention: wear a mask when ill, wash hands often, change out of wet clothes quickly and let sick staff stay home.

Cleaning and spraying: these viruses are named on WHD's pages. According to the service and product information, CHEMGENE HLD4H covers COVID-19, RSV and influenza H1N1. Spraying shared touchpoints after cleaning is a sensible extra measure for this area, together with good ventilation.

No. 5: Mold in lobby carpets and car interiors (Aspergillus, Penicillium)

Why it ranks here: carpet soaks up water and dries slowly, whether at a building entrance, in a meeting room or on the floor of a car driven through standing water. In Bangkok's heat and humidity, mold can grow and cause a musty smell. WHO and CDC advise cleaning and drying quickly, generally within 24 to 48 hours.

Where it hides: under car floor mats, in boot compartments, along carpet edges near glass doors and in fabric wall panels.

Symptoms: sneezing, blocked nose, itchy eyes and cough. People with allergies or asthma may feel worse in a musty car or room.

Prevention: take car mats out to dry, open car doors to air the cabin, use a wet vacuum, send large carpets for washing and throw away items that cannot be dried.

Cleaning and spraying: the service information states coverage of fungi in general. After drying, spraying reduces what remains on surfaces. The genera named here are not listed individually, so ask for test data if needed. If a closed room still smells musty, ozone disinfection is an add-on carried out in an empty space.

No. 6: Norovirus in food courts and office kitchens

Why it ranks here: a big junction area has food courts, restaurants and many office pantries. Norovirus spreads through hands, food and contaminated surfaces. If wastewater reaches a kitchen or washroom, or a staff member falls ill, it can spread through a group.

Where it hides: shared dining tables, microwaves, fridge handles in pantries, taps and toilets.

Symptoms: vomiting, diarrhoea and stomach pain, usually gone in a few days. Drink enough fluids and see a doctor if symptoms are severe.

Prevention: wash hands with soap, keep sick people off work until they recover and clean pantries and washrooms more often.

Cleaning and spraying: according to product information, CHEMGENE HLD4H covers norovirus, so spraying pantries and washrooms after cleaning helps lower surface risk.

No. 7: Skin fungi and Candida on feet from wet shoes

Why it ranks here: many workers keep wet shoes and socks on for hours. Trapped moisture lets dermatophytes and Candida grow between the toes. It is mild but very common and spreads in shared showers and washrooms.

Where it hides: shower floors in building gyms, bath mats and shared slippers.

Symptoms: itching between toes, peeling or white, soggy skin and odour. See a doctor or pharmacist if it does not improve.

Prevention: dry feet well, especially between toes, change socks often, dry shoes fully and do not share footwear.

Cleaning and spraying: the service information states coverage of fungi in general. Spraying washroom and shower floors after scrubbing reduces fungi on surfaces. These organisms are not listed individually; test data can be requested.

No. 8: Legionella in building water systems

Why it ranks here: Legionella does not come from road water. CDC notes, however, that building water systems left unused or under-used, for example while a building is closed or quiet after a disaster, can hold stagnant water that favours its growth. Large office districts should be aware of it. It ranks last because it is less linked to short-lived waterlogging than the others.

Where it hides: cooling towers, water tanks, showerheads and taps left unused for a long time.

Symptoms: fever, cough and breathing difficulty, similar to pneumonia. Older adults, smokers and people with chronic lung disease are at higher risk and should see a doctor if symptoms appear.

Prevention: have building engineers inspect and maintain water systems under the building's water management plan, and flush taps that have sat unused.

Cleaning and spraying: surface spraying is not how Legionella in water systems is managed; that requires building engineering measures. We mention it so managers do not overlook it. The product does not name it; it falls within the bacteria group.

Why routine mopping may not be enough after waterlogging at Bang Na junction

• The contaminated area is bigger than usual: wet footprints spread from the entrance to the lobby, lifts and office floors.
• Floor cleaners focus on cleaning: they lift dirt but are not designed to disinfect after sewage-tainted water.
• Bleach is harsh and strong-smelling: unsuitable for carpet, some stone and occupied offices, and never to be mixed with ammonia.
• Touchpoints are many and easily missed: lift buttons, handrails, card readers and glass door handles.
• Contact time is too short: a single wipe rarely leaves disinfectant on the surface for the time its maker specifies.

WHD post-flood disinfection spraying for buildings and homes near Bang Na junction

World Health Disinfection (WHD) is based in Bang Khae district, Bangkok 10160, and serves Bangkok and nearby provinces by appointment through 065-556-6294 or LINE @whd268. We have no branch in Bang Na and do not promise a same-day visit, because queues are long after floods. The team confirms a realistic date once it has details of the space.

Key facts according to WHD's service information:

• Trained technicians spray and/or use ULV (Ultra Low Volume) fogging for a fine mist.
• The disinfectant is CHEMGENE HLD4H, a medical-grade disinfectant from the UK containing Benzalkonium Chloride and Didecyldimethylammonium Chloride.
• The service page lists viruses, bacteria and fungi including COVID-19, RSV, H1N1, H5N1 and hand, foot and mouth disease virus, claiming 99.99%.
• It lists approvals and references from the Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019.
• Free CHEMGENE spray bottle and WELLGIENIC wet wipes with the service; tax invoices available.

Recommended sequence for office buildings

1. Send details: photos of the lobby, car park, shared washrooms and water-marked areas, plus approximate floor area.
2. Clean first: sweep debris, wash off silt and lift wet carpets for washing. Spraying does not replace washing.
3. Plan zones and timing: usually out of hours or floor by floor. People and pets leave the zone; cover documents and electronics.
4. Spray: floors, lower walls, lifts, handrails, washrooms and pantries.
5. Re-entry: the service page states about 30 minutes before normal use. Follow the time technicians give on site, and wipe food-contact surfaces as advised, since some product may remain.

10 reasons buildings and homes near Bang Na junction spray after cleaning

1. Many waders bring contamination indoors at once.
2. Fine mist reaches lift gaps, corners and under reception counters.
3. The CHEMGENE HLD4H spraying service uses a disinfectant WHD describes as medical grade.
4. Product information names COVID-19, RSV and H1N1, relevant to shared offices.
5. Work can be done out of hours.
6. Tax invoices suit building juristic persons and companies.
7. You can tell staff and tenants exactly what was done.
8. Cleaners no longer disinfect every point by hand.
9. Technicians explain precautions and re-entry time. Read the service details.
10. The free spray bottle and wipes help maintain touchpoints afterwards.

Before and after: an office lobby after a stormy evening

Three-place checklist: building, home and car

At the office: replace doormats and wash wet carpets; wash the lobby, car park and corridors; wipe touchpoints and book spraying after washing; have building staff check water and air conditioning systems.

At home: leave wading shoes outside and wash them before bringing them in; wash wet clothes separately; shower with soap and check feet and legs for wounds.

In the car: take mats out to dry and open doors to release moisture; if water entered the cabin or electrics misbehave, have a service centre check it; a musty smell means moisture is still trapped.

Health: fever, calf pain, diarrhoea or a red, swollen wound within one to two weeks of wading means a visit to the doctor.

FAQ: post-flood germs ranked at Bang Na junction

Q: Why are respiratory viruses ranked when they do not come from water?
A: The ranking looks at both the water and how people behave at a junction. During heavy rain more people shelter together indoors, so shared touchpoints need attention too.

Q: No water entered our building, but the lobby is full of wet footprints. Should we spray?
A: Wash floors and replace mats first. Where there are shared washrooms, pantries or busy touchpoints, spraying after cleaning adds confidence.

Q: Can you spray inside a car?
A: Ask the team case by case, since interior materials and electrics must be considered. The first priority is drying the car fully.

Q: When can staff return?
A: The service page says about 30 minutes, but follow the time technicians give on site.

Q: Does this prevent leptospirosis?
A: Spraying reduces germs on surfaces but does not prevent infection from wading on the road. The product information does not name Leptospira. Anyone with symptoms must see a doctor.

Get your building and home ready again with confidence

Once cleaning is done, let WHD plan zone-by-zone spraying with CHEMGENE HLD4H.

Request a disinfection spraying quote

Call 065-556-6294 | LINE @whd268

Related links and references

• WHD disinfection spraying service: https://www.worldhealthdisinfection.com/en/disinfection-service
• Residential ozone disinfection: https://www.worldhealthdisinfection.com/en/residential-ozone-disinfection
• Naewna, main-road waterlogging points, 25 Sept 2026: https://www.naewna.com/n/top-stories/81763/
• Naewna, 43 waterlogging points: https://www.naewna.com/n/bkk/81721/
• Thai PBS, rainfall: https://www.thaipbs.or.th/news/content/558661
• Thai PBS, assistance zones: https://www.thaipbs.or.th/news/content/558867
• Bangkok Biz News, 329,000 households: https://www.bangkokbiznews.com/news/news-update/1255155
• WHO fact sheets: https://www.who.int/news-room/fact-sheets
• CDC flood guidance: https://www.cdc.gov/floods/
• Thailand Department of Disease Control: https://ddc.moph.go.th/