Example Case: A Ground-Floor Flat in Sai Mai Where the Floor Still Did Not Feel Safe

The story below is a typical scenario compiled from situations that are common after floods. It is not an interview with a real person.

Prae rents a ground-floor unit in a residential block off Sai Mai Road. She lives with her husband, their three-year-old son and her mother, who is nearly seventy. In late September 2026 the water crept up from the car park to the front door. The family moved their bedding to a relative's flat upstairs for several days.

When the water receded in early October, she and her husband shovelled out the mud, scrubbed the floor with household floor cleaner and ran fans all day. Even so, a stale odour kept drifting out from the corners of the wardrobe and from under the bed. A brown tide line ran along the bottom of the walls, and the bathroom drain smelled foul from time to time. Her mother began coughing at night, and her son wanted to crawl on the floor as he always had. Prae was left with the same question many Sai Mai families are asking: the flat looks clean, but is it safe?

The honest answer is that washing removes visible dirt, but some germs remain in tile grout, along door frames, under the sink and on surfaces hands touch all day. Systematic disinfection after cleaning adds another layer of protection.

The 2026 Flood in Sai Mai: Facts From BMA, DDPM and News Reports

The points below come from news reports and announcements with clear dates. Water levels change daily, so always check the latest notices from the Bangkok Metropolitan Administration (BMA) and the Sai Mai district office before you move back in.

• 26 September 2026: the BMA declared all 50 Bangkok districts disaster areas after prolonged heavy rain.
• 26 to 29 September 2026: Thai PBS reported that the Ua Arthorn Khlong Thanon housing project on Soi Phoemsin 24/1, which has 87 buildings and about 10,000 residents, had water roughly 30 to 80 centimetres deep, reaching waist height in places.
• 29 September 2026, 18:52: the Department of Disaster Prevention and Mitigation (DDPM) sent a Cell Broadcast alert to people in three districts, Sai Mai, Khlong Sam Wa and Nong Chok, warning that water could overtop the embankment along Khlong Hok Wa Sai Lang on the Pathum Thani border, and asking residents to move belongings to higher ground (Naewna).
• 29 to 30 September 2026: the BMA listed Sai Mai as one of 15 districts with a high level of impact, covering 748 communities across those 15 districts (Posttoday and Dailynews on 30 September; Prachatai citing a BMA notice of 29 September).
• 4 October 2026, 12:11: Sai Mai Road between Soi 27 and Soi 35 still had standing water of about 5 centimetres (Krungthep Turakij).
• 5 October 2026: the BMA was still warning the three districts bordering Pathum Thani about the risk of Khlong Hok Wa Sai Lang overflowing, and Sai Mai was one of four districts where the BMA set up mobile pumps, together with Lat Krabang, Khlong Sam Wa and Saphan Sung (Siamrath).
• 6 October 2026: more than 49,000 households had registered for flood relief on claim.bangkok.go.th by 08:30, with Lat Krabang, Bang Kapi and Sai Mai registering the most (Manager Online).

Taken together, these facts show that Sai Mai did not flood for a single day. Residents had to stay alert for close to two weeks, both because of heavy rain and because Khlong Hok Wa Sai Lang was carrying water from the Pathum Thani side. Dense housing such as Ua Arthorn Khlong Thanon also has many shared stairwells, lifts, handrails and corridors. The BMA has also told residents to prepare for another round of rain from 10 to 13 October 2026, which is one more reason to finish the recovery work quickly and properly.

The National Picture: DDPM Data as of 7 October 2026, 06:00

The Government Public Relations Department and Thai PBS published DDPM figures on 7 October 2026. Floods were affecting 27 provinces plus Bangkok, covering 123 districts, 984 subdistricts and 7,215 villages. In total, 1,154,875 households, or more than 3.1 million people (3,160,972), were affected. DDPM attributed the floods to heavy to very heavy rain in many areas combined with water flowing down from the North. In Bangkok, about 329,000 households were affected, and the figure was falling.

Provinces where water levels were still rising, according to the DDPM report of 7 October, were Sing Buri, Suphan Buri, Ang Thong, Phra Nakhon Si Ayutthaya, Samut Prakan, Pathum Thani, Ratchaburi, Samut Songkhram, Prachin Buri and Chachoengsao. Nakhon Nayok was stable on 6 and 7 October. Thai PBS reported that DDPM continues to monitor the situation 24 hours a day. These numbers change every day and should be read as a snapshot for the date given.

Post-Flood Disinfection in Pathum Thani: The Latest Situation

Pathum Thani is Sai Mai's closest neighbour. Water from the canals on the Pathum Thani side flows into Khlong Hok Wa Sai Lang before entering Bangkok's northern and eastern drainage network, so what happens there affects Sai Mai directly. According to the DDPM data as of 7 October 2026, Pathum Thani had seven affected districts: Thanyaburi, Mueang Pathum Thani, Sam Khok, Khlong Luang, Lam Luk Ka, Nong Suea and Lat Lum Kaeo. That covers 60 subdistricts and 507 villages, with 246,818 households affected, the highest of any province outside Bangkok, and water levels were still rising.

The household figure rose from 169,724 on 4 October to 246,818 on 7 October. Thai PBS reported at 07:37 on 6 October 2026 that some communities in Nong Suea had been flooded for more than two weeks, with a plan to drain water through Khlong 14 and Khlong 13 into Khlong Hok Wa Sai Lang. In Khlong Luang, the Pruksa 12 housing estate had been under water for about ten days, affecting more than 3,000 households, and pumping continued along Khlong Rangsit Prayoonsak.

This explains why the DDPM and BMA warnings named Sai Mai, Khlong Sam Wa and Nong Chok together. When Pathum Thani speeds up drainage into Khlong Hok Wa Sai Lang, communities on the Bangkok side of the canal must watch the water too. For homes in Pathum Thani that were flooded for ten days or more, mud and stagnant water often let mould grow deep into absorbent materials such as plywood, ceiling boards and gypsum walls. Post-flood disinfection in Pathum Thani should therefore begin only after damaged materials have been removed and the home has been washed and dried.

WHD is based in Bang Khae, Bangkok 10160, and has no branch in Pathum Thani, but jobs in Pathum Thani can be arranged by phone at 065-556-6294 or LINE @whd268. Same-day service cannot be promised, because demand is high while floods recede.

Germs That Floodwater Brings Into Sai Mai Homes and Housing Blocks

Urban floodwater is not clean rainwater. It runs through drains, manholes, bins and septic tanks before it reaches a home, and when it recedes it leaves sediment and microorganisms on every surface it touched. The World Health Organization (WHO), the US Centers for Disease Control and Prevention (CDC) and Thailand's Department of Disease Control all give the same advice: surfaces touched by floodwater should be cleaned first and then disinfected. The germs worth knowing about fall into a few broad groups.

Bacteria from sewage

Gut bacteria from people and animals, such as E. coli and Salmonella, often travel with sewage and overflowing septic tanks. When hands touch a contaminated surface and then touch food, the result can be diarrhoea, stomach cramps, nausea or vomiting. In a ground-floor flat the places to watch are the bathroom floor, floor drains, door frames and the kitchen floor.

Leptospirosis

Floods drive rats to higher ground and into buildings. Leptospira bacteria from rat urine can be present in standing water and mud and can enter the body through cuts or mucous membranes. People who wade for long periods, or who clean without boots and gloves, are at risk. Warning signs include high fever, headache and marked pain in the calf muscles.

Viruses spread by surfaces and crowding

Norovirus and rotavirus cause diarrhoea, while hand, foot and mouth disease and RSV are common in young children. During a flood many people share a relative's flat or a shelter and use the same lifts and stairs, so viruses have more chances to pass from hand to surface to hand.

Mould and musty smells

After the water drops, moisture trapped in walls, ceilings, wooden cabinets, mattresses and curtains gives mould exactly what it needs. CDC advises cleaning and drying within 24 to 48 hours to limit mould growth. Mould spores can trigger allergies, asthma, coughing, sneezing and a blocked nose, especially in older people and children. A musty smell that survives days of fans usually means moisture or mould is still inside the materials.

Who Is Most at Risk in Sai Mai, and When to See a Doctor

These groups need extra care after the water recedes:

• Young children, who crawl and put things in their mouths.
• Older people, whose immunity is lower and who may already have lung conditions or allergies.
• Pregnant women, who should avoid wading and direct contact with cleaning chemicals.
• People with chronic illness, such as diabetes or kidney disease, or anyone on immune-suppressing medicine.
• The people doing the cleaning, who handle mud and standing water longer than anyone else, especially if they have cuts on their hands or feet.

See a doctor promptly for high fever with calf pain after wading, repeated diarrhoea or signs of dehydration, a rash or wound that becomes red, swollen or pus-filled, a cough or breathing problem that is getting worse, or a child with fever and blisters in the mouth or on the hands and feet. Disinfection reduces germs on surfaces at home. It is not a treatment, and anyone with symptoms should be checked by a doctor.

What Happens When Germs Are Left Behind

Health: family members may fall ill again and again with diarrhoea, coughs or allergy flare-ups without realising the cause is in their own home.

Money: mould that spreads into furniture, ceilings and walls means more demolition and replacement later, while medical bills and lost workdays add to the burden on families already hit by the flood.

Why Washing Alone Is Not Enough

Sai Mai families have worked extremely hard to clean their homes, but the usual methods have limits worth knowing:

• Ordinary floor cleaner removes stains and smells, but most products are not designed to disinfect a broad range of germs on surfaces exposed to sewage.
• Pouring bleach without washing first means the disinfectant cannot reach the germs, because mud and grease still coat the surface. Mixing bleach with other products can also release dangerous fumes.
• Fans and air conditioning help things dry, but they do not disinfect and can spread mould spores around the room.
• Painting over mould hides it, but mould under the paint keeps growing while the wall is damp.

The approach recommended by CDC and the Department of Disease Control is to remove mud and damaged items, wash with water and a cleaning agent, let everything dry, and then disinfect. Spraying by trained technicians handles that final step and reaches more of the space than wiping by hand.

How the WHD Disinfection Service Works in Sai Mai

According to WHD's service information, trained technicians spray and/or apply ULV (Ultra Low Volume) fine-mist fogging using CHEMGENE HLD4H, a medical-grade disinfectant from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride. The service page describes it as broad-spectrum against viruses, bacteria and fungi, listing examples such as COVID-19, RSV, H1N1, H5N1 and hand, foot and mouth virus, with a claimed 99.99% efficacy. The page also lists approvals and endorsements from the Department of Medical Sciences, Mahidol University, NHS England and the EN 14476:2013+A2:2019 standard.

For organisms that are not named on the page, such as E. coli or Leptospira, we do not claim a specific test result. They belong to the bacteria group the product says it covers. If you need test data for a particular organism, ask the WHD team directly.

Step by step in Sai Mai homes and buildings

1. Survey: the team asks about floor area, how high the water rose, the number of rooms, shared areas and damaged materials, by phone or LINE with photos.
2. Mud removal and washing first: spraying takes place only after mud has been removed, damaged materials taken out and surfaces washed, because residue reduces the disinfectant's effectiveness.
3. Zoning: technicians divide the space into zones such as bedrooms, kitchen, bathroom, corridors and shared stairwells so that nothing is missed.
4. People and pets leave: residents, children, older people and pets leave the zone being sprayed, and food, dishes and children's toys are stored away.
5. Spraying: high-touch and high-risk surfaces are treated, including floors, lower walls, door frames, handles, rails, bathrooms and under-sink areas, with fine-mist fogging in suitable rooms.
6. Re-entry: according to the service information, wait about 30 minutes, or as long as the technicians advise, before using the space normally, and ventilate as instructed.

Do not assume that spraying leaves nothing behind. Follow the technicians' advice about wiping food-contact surfaces and about re-entry times. For a stale smell that lingers in the air, residential ozone disinfection is available as a complementary service.

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. Prices depend on area and conditions, so please ask for a quotation.

10 Reasons Sai Mai Homes Should Disinfect After the Flood

1. The flood lasted a long time. Warnings and mobile pumps ran from late September into early October, and long-standing water carries more germs and sediment.
2. Housing blocks have busy shared spaces. Stair rails, lifts and entrance doors pass germs from person to person. A professional disinfection service treats these points thoroughly.
3. It protects young children and older people, the groups most likely to fall ill after a flood.
4. Medical-grade disinfectant. CHEMGENE HLD4H is described on the service page as broad-spectrum against viruses, bacteria and fungi.
5. Trained technicians know the right order of work and how to protect themselves and residents.
6. It reaches places hands cannot, such as under furniture, behind cabinets and along skirting boards.
7. It helps reduce germ-related odours when combined with thorough drying.
8. It is quick. According to the service information, you can usually return after about 30 minutes, so families do not need to move out for days.
9. It prepares you for the next rain. The BMA has asked residents to prepare for rain from 10 to 13 October 2026. Book a spraying slot in advance via LINE.
10. It reassures tenants and customers of landlords, shops and building managers in Sai Mai, and a tax invoice is available.

Before and After Spraying: What Sai Mai Families Notice

Example Case: A Townhouse Near Sai Mai Road

This is an illustrative scenario used to explain the process. It is not a real customer review.

Ton owns a two-storey townhouse in a soi near Sai Mai Road. About a hand-span of water entered the ground floor, reaching the living room and kitchen. When the water went down he carried out the soaked sofa and the swollen wooden cabinet under the sink, washed the floor with clean water and detergent, and left the doors and windows open for two days. He then contacted WHD on LINE @whd268 and sent photos for assessment.

On the appointment day the technicians checked that the floor was dry and split the work into three zones: living room, kitchen and downstairs bathroom. Ton's family took their cat upstairs and closed the door during spraying. The team treated the floor, lower walls, door frames and the area under the sink, then told the family how long to wait before coming back down. Afterwards Ton wiped the food-preparation counter as advised and will replace the lower wall if mould reappears.

Recovery Checklist for Sai Mai Homes

Before spraying day

• Check BMA and Sai Mai district notices to confirm it is safe to return, and have the electrics inspected.
• Wear boots, rubber gloves and a mask while removing mud and washing.
• Remove absorbent, damaged items such as mattresses, carpets and swollen ceiling boards.
• Wash floors and walls with clean water and detergent, and never mix different chemicals.
• Open doors and windows to dry the home as much as possible.
• Send photos to WHD on LINE @whd268 for assessment.

On the day

• Store food, dishes and children's toys in closed containers.
• Make sure everyone, including pets, leaves the zone being sprayed.

After spraying

• Wait for the time the technicians advise before going back in.
• Ventilate, and wipe food-contact surfaces as instructed.
• Watch for mould and musty smells over the next one to two weeks.
• If anyone develops fever, diarrhoea or calf pain, see a doctor.

FAQ: Disinfection Service in Sai Mai

Does WHD work in Sai Mai?
Yes. WHD serves Bangkok, including Sai Mai. Book by phone at 065-556-6294 or LINE @whd268. The office is in Bang Khae, and dates are confirmed according to the schedule, so same-day service is not guaranteed.

Do I need to clean before spraying?
Yes. Spraying is done after mud has been removed and surfaces washed, because dirt reduces the disinfectant's effectiveness.

Do we have to leave during spraying?
People, children, older relatives and pets must leave the zone being sprayed and return when the technicians say so, generally about 30 minutes according to the service information.

Can you treat shared areas of a housing block?
Yes. Juristic persons can request an assessment of stairwells, corridors, lifts and bin rooms, and the work can be zoned to limit disruption for residents.

Will spraying stop us getting sick?
Disinfection reduces germs on surfaces, but it is not a cure and cannot prevent every illness. Keep washing hands, drink safe water and see a doctor if symptoms appear.

House Washed in Sai Mai? Let WHD Finish the Job With Disinfection

Flats, townhouses, canal-side homes, shops or the shared areas of a building, in Sai Mai or in Pathum Thani: contact WHD for an assessment and a booking.

Book Disinfection in Sai Mai

Call 065-556-6294  |  LINE @whd268

World Health Disinfection, Bang Khae, Bangkok 10160

Related Services

• WHD Disinfection Spraying Service
• CHEMGENE HLD4H disinfectant
• Residential Ozone Disinfection

References

• Government Public Relations Department, DDPM report, 7 Oct 2026: prd.go.th
• Thai PBS, 7 Oct 2026: thaipbs.or.th/news/content/559271
• Thai PBS, 4 Oct 2026: thaipbs.or.th/news/content/559135
• Thai PBS, Ua Arthorn Khlong Thanon: thaipbs.or.th/news/content/558868
• Thai PBS, Pathum Thani, 6 Oct 2026: thaipbs.or.th/news/content/559201
• Naewna, Cell Broadcast, 29 Sep 2026: naewna.com
• Krungthep Turakij, 4 Oct 2026: bangkokbiznews.com
• Siamrath, 5 Oct 2026: siamrath.co.th
• Manager Online, 6 Oct 2026: mgronline.com
• Posttoday, 15 high-impact districts: posttoday.com
• CDC Floods: cdc.gov/floods
• WHO fact sheets: who.int
• Department of Disease Control, Thailand: ddc.moph.go.th