What happened in Saphan Mai, Bang Khen

According to a report by Prachatai, flooding in the Saphan Mai area of Bang Khen district, Bangkok, began on 26 September 2026. By 29 September, the fourth day, the water had still not gone. The report focused on Soi Phahonyothin 69/5 to 69/8 and Soi Chokdee 1 to 4, a densely populated residential area with canal-side communities and side lanes branching off the main road.

Prachatai reported that in canal-side communities and some lanes next to the road, the water was nearly waist-deep. For single-storey homes the immediate consequence was that toilets could not be used and food could not be cooked, because every living space sat at the same level as the water. Residents had to improvise just to get through each day.

The report also noted that the standing water smelled bad, a clear sign that it was not still, clean water but water that was going stale and was likely contaminated from several sources. Some shops in the area had closed, affecting both the owners' income and residents' ability to buy food and daily essentials nearby.

Prachatai reported that 29 September 2026 was the first day the sun came out after days of rain and cloud. For the community, that first sunny day was the signal that recovery could start, and it is a moment worth planning carefully, because what gets done in the first few days after the water drops largely decides how quickly a home becomes liveable again.

Note: the information above is based on the Prachatai report as of 29 Sept 2026. Flood conditions change daily, so please also follow announcements from the Bang Khen District Office and the Bangkok Metropolitan Administration.

Why "the toilet doesn't work" is a big hygiene issue

It is easy to think of an unusable toilet as an inconvenience. From a hygiene point of view it is a turning point. When flood water inside a house reaches or rises above the level of the toilet bowl, household sanitation may stop working properly. Septic tanks or inspection chambers may be submerged, and waste can mix into the water standing in homes and lanes.

That means the water on the floor may not be just rain mixed with soil. It may carry germs from human waste. When the water goes down, the film it leaves on floors, walls, table legs and furniture can carry those germs too. With the report noting that the standing water smelled foul, there is every reason to treat each surface the water touched as contaminated until it has been washed and disinfected.

Being unable to cook matters as well. Many households fall back on ready-made meals, donated food or food bought elsewhere. The risk of stomach illness rises during this period, both from food stored too long without a working fridge and from hands that are not washed properly because clean water is scarce. Once the kitchen can be used again, it needs to be made safe before the first meal is cooked.

There is also the question of drinking water. During and after a flood, tap water and stored water may be unsafe if containers were submerged or pipes were damaged. Health agencies generally advise using bottled water or water that has been boiled for drinking, cooking, brushing teeth and preparing baby formula until the supply is confirmed safe. This is a simple step that prevents a lot of illness while the rest of the clean-up is under way.

Example case: Auntie Somjai's single-storey house by the canal

This is an illustrative scenario based on problems commonly seen in single-storey homes after floods. Auntie Somjai is not a person from the news report.

Auntie Somjai is in her sixties and lives in a single-storey house in a narrow canal-side lane with her four-year-old grandson. During the flood they lifted the mattress onto a table, used a relative's toilet in a two-storey house at the end of the lane, and ate boxed meals that volunteers handed out. Four days later the sun finally came out. The water inside dropped, leaving a layer of sticky mud almost an inch thick and a smell so strong she had to cover her nose.

She shovelled out the mud, splashed water over the floor and quickly put the mattress back so her grandson could sleep comfortably. The plates and bowls that had been under water were washed with ordinary dish soap and used again. Two days later her grandson had loose stools, and a cut on her foot from wading had turned red and swollen.

Auntie Somjai did nothing wrong on purpose. She was in a hurry and did not know the right order of steps. A mattress soaked in dirty water should be considered for disposal. Dishes should be washed and then disinfected. The floor where her grandson crawls should be disinfected after the mud is removed. And a red, swollen cut after wading should be checked by a doctor. The sections below explain why each step matters.

Germs that may linger after days of stagnant water, room by room

The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) warn that flood water can be contaminated with sewage, chemicals and disease-causing organisms. Thailand's Department of Disease Control regularly warns the public about flood-related illnesses such as diarrhoeal disease, leptospirosis, skin infections and conjunctivitis. For a canal-side home like those in Saphan Mai, it helps to look at the risks room by room.

Bathroom and the area around the toilet

This is where contamination from faeces is most likely. Bacteria such as E. coli and Salmonella, and viruses such as norovirus and rotavirus that cause diarrhoea and vomiting, can sit on the toilet bowl, the bathroom floor, water scoops, taps and the lower walls. The bathroom must be thoroughly washed and disinfected before it is used again.

Kitchen and food preparation areas

Counters, chopping boards, dishes, cutlery and food cupboards that went under water are a shortcut for germs into the mouth. Any food that touched flood water should be thrown away, including packaged food that was not completely sealed. Durable items such as ceramic plates and stainless steel pots can be washed and then disinfected. Wooden chopping boards that soaked in dirty water for a long time are hard to rescue and are better replaced.

Floors and lower walls

Mud left on floors collects many kinds of germs, including Leptospira, the bacteria behind leptospirosis, carried in the urine of rats fleeing the water. People who scoop mud with bare hands or walk barefoot can be infected through cuts. The key signs are a sudden high fever, muscle pain especially in the calves, and red eyes. Anyone with these symptoms after wading should see a doctor quickly.

Bedrooms and children's play areas

Mattresses, pillows, blankets, rugs and soft toys that soaked in dirty water hold germs and moisture deep inside, which makes mould and musty smells very likely. Young children who crawl or sit on the floor and put their hands in their mouths are more exposed than adults. Viruses common in children, such as the hand, foot and mouth disease virus, also spread through shared surfaces and toys.

The air inside the house

A house that has been shut for days during a flood builds up high humidity. Mould starts to grow in wall corners, wooden cabinets and around door frames. Mould spores float in the air and trigger allergies, asthma and a blocked nose. At the same time, people crowding together during the flood, at relatives' homes or in shelters, increases the chance of spreading respiratory viruses such as influenza and RSV.

Who in the household needs extra care

• Young children: they crawl, touch floors and put their hands in their mouths, so they face a higher risk of diarrhoea and hand, foot and mouth disease.
• Older adults: weaker immunity, slower wound healing, and a faster slide into dehydration if they get diarrhoea.
• People with chronic illness: such as diabetes, kidney disease or lung disease, for whom infections can be more severe.
• Pregnant women: should avoid wading and scrubbing work that involves direct contact with mud.
• Whoever does the heavy cleaning: direct contact with mud and sewage-tainted water raises the risk of leptospirosis and infected wounds.
• Food stall and shop owners: who will serve the community again. If their premises are not clean, germs can reach many customers.

Anyone with a high fever, calf pain, red eyes, diarrhoea that will not stop, heavy vomiting, or a wound that is red, swollen or oozing should see a doctor right away and mention contact with flood water. Disinfectants reduce risk from surfaces. They are not medicine.

Splash, mop, pour bleach: why it is still not enough

After the water drops, many people do the same thing: scoop out the mud, splash water around, mop with floor cleaner and pour bleach into the bathroom. That is definitely better than nothing, but it leaves several gaps.

Everyday floor cleaners are made for routine cleaning, not for large amounts of sewage residue and faecal germs. If one mop is used for the whole house, germs from the bathroom can be carried straight into the bedroom and kitchen.

Bleach works when it is mixed correctly, and many health agencies recommend it in emergencies. But in a single-storey house with poor airflow, the sharp chlorine smell can irritate the nose and lungs, especially for children and older people. Worse, using bleach together with acidic toilet cleaners or ammonia-based products can release toxic gas, a mistake that happens surprisingly often when people are rushing to clean.

Chlorine corrodes some materials, including certain metals, hinges and aluminium door frames, and can fade or damage fabrics and some surfaces. For shops with metal shelving, display fridges and stainless steel equipment, that cumulative damage is not trivial.

Once dry, the effect is gone. Ordinary products work while the surface is wet. When it dries, the surface is ready to pick up new germs straight away. As the family moves back in, walks in and out, and children start crawling on the floor again, continuity of protection matters.

The answer after washing: CHEMGENE HLD4H, a medical-grade disinfectant

Once the mud is out and surfaces have been washed, the finishing step that reduces risk in a principled way is disinfection with a well-documented product. CHEMGENE HLD4H is a medical-grade, high-level disinfectant made in England. According to the product information:

• It lists activity against bacteria, fungi and mould, mycobacteria, Salmonella and many viruses, including influenza H1N1, RSV, norovirus, hand, foot and mouth disease virus and SARS-CoV-2.
• The product page states it kills within 1 minute, with 99.85% efficacy against COVID-19.
• It states residual surface protection of up to 14 days.
• It can be diluted at 1:30, 1:50, 1:60, 1:100 and up to 1:200.
• It is biodegradable and non-corrosive to stainless steel, aluminium, rubber, plastic and fibreglass.
• The product page says it is safe for people, pets and medical equipment when used as directed.
• Listed tests and approvals include Mahidol University, NHS England, ISO 9001:2015, ISO 13485, SGS, Intertek, CE, and EN 13727, EN 14348, EN 13624 and EN 14476.
• It is used in hospitals, clinics, laboratories, schools, offices, airports, homes, and elderly and child care settings.

For a single-storey home with young children and older relatives, what stands out is that there is no harsh chlorine smell, it suits many household surfaces from the bathroom and kitchen to the play area, and it has stated residual protection, which is useful in the days when the whole family has just moved back in.

Recovery order for a single-storey home, starting from the first sunny day

1. Check the electrics first. If sockets or wiring were under water, do not switch anything on yourself. Have an electrician inspect first.
2. Wear protection. Boots, rubber gloves, a mask, and cover any cuts completely.
3. Open up the house. Make the most of the sunny day and open every door and window.
4. Sort your belongings. Throw away food that touched the water, and mattresses, pillows, rugs and soft toys soaked in dirty water that cannot be saved. Set aside durable items for washing.
5. Remove all the mud, then wash floors, lower walls and furniture with clean water and detergent. Scrub again until no residue is left.
6. Keep cleaning tools separate. Use different cloths and mops for the bathroom and the rest of the house.
7. Wipe dry or let surfaces dry. Dry surfaces help the disinfectant stay at its intended concentration.
8. Dilute Chemgene HLD4H as shown on the label. The product information lists rates from 1:30 to 1:200. Choose according to the area being treated, following the label and supplier advice. Never mix with other cleaners.
9. Work from highest to lowest risk. Start with the bathroom, kitchen and play area, then move to the rest of the floors and walls. Leave the solution in contact for the time stated on the label.
10. Wash your hands after every job and before eating.

The easy rule: wash off the mud, dry, then disinfect per label. No disinfectant can work through a layer of mud, so washing is the step you cannot skip.

10 reasons canal-side homes should finish with Chemgene HLD4H

1. Made for bathrooms that stopped working. Chemgene HLD4H lists activity against diarrhoea-causing germs such as Salmonella and norovirus.
2. Medical grade. It is a high-level disinfectant according to the product information, not an ordinary household cleaner.
3. No harsh smell, which suits single-storey homes with limited airflow, children and older relatives.
4. Fast stated action. The product page states 1 minute, so you can move room by room quickly.
5. Residual protection of up to 14 days, as stated, while the whole family settles back in.
6. Non-corrosive to household and shop materials, including stainless steel, aluminium, rubber and plastic found in sinks, door frames, basins and shelving.
7. Covers viruses common in children, including hand, foot and mouth disease virus and RSV.
8. Economical when diluted. Several rates from 1:30 to 1:200 mean one bottle can cover the whole house and be shared with neighbours in the lane.
9. Biodegradable, a good fit for canal-side homes whose wastewater returns to the environment.
10. Clear list of approvals, including Mahidol University, NHS England, SGS and Intertek. Learn more on the Chemgene HLD4H product page.

Before and after: one single-storey house off Soi Chokdee

Checklist for Saphan Mai shops reopening after a temporary closure

Prachatai reported that some shops in the area had to close. When the water drops and they are ready to reopen, these shops become the places residents visit most, so their cleanliness affects the health of the whole lane.

• Throw away food and drink stock that touched flood water, including anything not fully sealed.
• Have fridges and display coolers checked by a technician before plugging them in, then clean inside and out.
• Wash shelving, the checkout counter and the floor with detergent, then dry.
• Disinfect surfaces that customers and staff touch often with Chemgene HLD4H according to the label.
• For food stalls, wash and disinfect chopping boards, knives, utensils and prep areas before selling.
• Provide a handwashing point or hand sanitiser for customers.
• Keep the shop ventilated and check for musty smells or mould the following day.

A canal-side community recovers together

Homes in narrow canal-side lanes sit close together, share walkways and use the same drainage. If one house is washed and disinfected well but the path outside is still covered in rotting mud, germs simply come back in on people's shoes. Getting neighbours together to wash shared walkways, wooden bridge rails and shared steps, then disinfecting the spots hands touch most, makes the whole lane much safer than everyone working alone.

One approach that works is dividing tasks by ability. Younger people take on the heavy work like shovelling mud, while older residents and pregnant women help with tasks that avoid direct contact with mud, such as preparing clean water, sorting belongings, or keeping children away from work areas. A disinfectant that can be diluted at several rates also makes it practical to share supplies across several households.

Keep an eye on each other's health after the water drops, too, especially people who waded for several days. If someone develops a high fever, calf pain or severe diarrhoea, help them get to a doctor as soon as possible.

Frequently asked questions

The water in my house still smells. Can I disinfect now?
Wait until the water has gone, remove the mud and wash surfaces first. Disinfecting on top of mud or in standing water does not work properly. Once surfaces are clean and dry, use Chemgene HLD4H according to the label.

The toilet was unusable for days. Where do I start?
First check that drainage and the septic tank are working. If there are still problems, contact a plumber or the relevant authority. Then wash the toilet bowl, floor, lower walls, taps and water scoops with detergent, and disinfect at the label dilution.

Half my mattress was under water. Can I disinfect it and keep using it?
Mattresses and other materials that have absorbed dirty water deep inside usually cannot be made truly clean. Health agencies generally advise discarding absorbent items soaked in flood water. Disinfection is for hard, washable surfaces.

Can I use it on dishes?
Wash durable dishes with dish soap and clean water first, then disinfect according to the product label's guidance for food-contact surfaces, and rinse with clean water if the label says so.

I have a toddler and a cat. Is it OK to use?
The product page says it is safe for people and pets when used as directed. Keep children and animals out of the area while spraying or wiping, let it dry for the stated time, and store the product out of children's reach.

Can I mix it with bleach to make it stronger?
Do not mix any disinfectant with other chemicals. Use it on its own according to the label. Mixing can reduce effectiveness or create irritating fumes.

Make your home in the lane liveable again

Ask about using CHEMGENE HLD4H for homes, bathrooms, kitchens and shops after the flood. The team can advise on the right dilution and quantity for your space.

Order and view Chemgene HLD4H

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

Related links and references

• CHEMGENE HLD4H medical-grade disinfectant
• Ozone odour and chemical-residue removal
• Residential ozone disinfection service
• Prachatai report on the Saphan Mai flood: https://prachatai.com/journal/2026/09/118932
• World Health Organization fact sheets: https://www.who.int/news-room/fact-sheets
• CDC floods and clean-up: https://www.cdc.gov/floods/
• Thailand Department of Disease Control: https://ddc.moph.go.th/

Product information is taken from the supplier's product page. Disinfectants help reduce the risk of infection from surfaces. They do not prevent flooding and are not medical treatment. Anyone who is ill should see a doctor. Always follow the label.