Example Case: A Shophouse Near Phong Phet Junction Where Road Water Swept Into the Shop

This is a typical scenario compiled from common situations. It is not the story of a real person.

Wit runs a phone and IT repair shop on the ground floor of a shophouse near Phong Phet junction, with his family living upstairs. On the night of 25 September 2026 the rain did not stop. By the next morning Ngam Wong Wan Road outside had become a channel of water, and every passing car pushed a wave into the shop. Murky water carrying litter from the drains ran under the display cases and the counter.

Once the road dried, Wit and his staff scrubbed the floor and wiped the glass cabinets until everything looked tidy. Yet a drain smell still rose now and then, the lower wall behind the cabinets had a water stain, and the space under the stairs where he stores boxes was still damp. Dozens of customers put their phones on his counter every day, and his school-age daughter walks through the shop to get upstairs. He began to wonder whether a shop that so many hands touch needed more than an ordinary wipe-down.

Many shophouse owners, condo managers and office building managers in Lak Si are asking the same thing. Road floodwater brings whatever was in the drains with it. Cleaning makes a space look right, while systematic disinfection lowers the risk on surfaces that many people share.

The 2026 Flood in Lak Si: Facts From News Reports and BMA Notices

The points below come from dated reports. Depths are road readings at the time given. Conditions change daily, so check the latest notices from the Bangkok Metropolitan Administration (BMA) and the Lak Si district office.

• 25 to 26 September 2026: Ngam Wong Wan Road had about 12.5 centimetres of standing water, starting at 22:25 on 25 September, and Chaeng Watthana Road about 10.3 centimetres (Thai PBS).
• 26 September 2026: the BMA flood prevention centre issued an alert listing flooded points where small vehicles should not pass, including Phong Phet junction on Ngam Wong Wan Road, Chaeng Watthana Road between Lak Si junction and the Government Complex, and Vibhavadi Road in front of the Chatuchak district office and Thai Airways. The same day, inbound Vibhavadi Rangsit between Don Mueang air force base and Lak Si junction had water of about 40 centimetres (Thai PBS, Thansettakij, Manager Online). The BMA also declared all 50 districts disaster areas.
• 27 September 2026: Vibhavadi Rangsit in front of Thai PBS in Lak Si was impassable for small vehicles for about two kilometres, with construction work reported to be blocking drainage (Thai PBS).
• 28 September 2026, 09:27: the Drainage and Sewerage Department measured 32.8 centimetres at Phong Phet junction on Ngam Wong Wan, the fourth-highest reading in Bangkok at that time, and 23.2 centimetres near Soi Chinnakhet (Siamrath).
• 29 September 2026: Ngam Wong Wan near Soi Chinnakhet and near Khlong Prem prison were still flood points (Thai PBS).
• 29 to 30 September 2026: the BMA listed Lak Si among 15 districts with a high level of impact, together covering 748 communities (Posttoday and Dailynews, 30 September; Prachatai citing a BMA notice of 29 September).
• 3 October 2026: Ngam Wong Wan and Chaeng Watthana were dry and traffic was back to normal (Thai Post).

In short, Lak Si's main roads flooded heavily between 25 and 29 September and were dry again by early October. We are not claiming these points are flooded now. But while the water was high, drain and road water entered shophouses, basement car parks, condo lobbies and office entrances in many places, all of them spaces that large numbers of people share every day. The BMA has also asked residents to prepare for more rain from 10 to 13 October 2026.

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

DDPM data published by the Government Public Relations Department and Thai PBS on 7 October 2026 showed floods in 27 provinces plus Bangkok, covering 123 districts, 984 subdistricts and 7,215 villages, with 1,154,875 households, or more than 3.1 million people (3,160,972), affected. DDPM cited heavy to very heavy rain and water flowing from the North. About 329,000 households were affected in Bangkok, a figure that 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 round-the-clock monitoring. These are snapshot figures for the date given.

Post-Flood Disinfection in Nonthaburi: The Latest Situation

Nonthaburi borders Lak Si and the Chaeng Watthana area, and many people live on one side and work on the other. The first fact to know is that Nonthaburi was not on the list of affected provinces in the DDPM reports of 4, 6 and 7 October 2026, so those reports give no affected-household figure for Nonthaburi.

Nonthaburi did, however, receive warnings in the same period. On 29 September 2026 DDPM sent a Cell Broadcast alert to residents of Mueang Nonthaburi, Pak Kret and Bang Kruai living outside the flood walls along the Chao Phraya River (Krungthep Turakij). The Nonthaburi DDPM centre warned that from 29 September to 5 October the Chao Phraya would rise by about 0.20 to 0.40 metres, as the Chao Phraya Dam released 2,200 to 2,400 cubic metres per second and high tides pushed water upstream (Matichon).

Homes outside the flood walls are often wooden houses, piers, riverside shops and old communities used to tidal water. If water entered a ground floor at high tide, even briefly, it would leave sediment and moisture behind. For those homes, post-flood disinfection in Nonthaburi should follow once it is safe, the sediment has been washed out and the building has dried. For homes that stayed dry, cleaning entrances, doors and frequently touched surfaces after family members come home from wading is still good hygiene.

WHD is based in Bang Khae, Bangkok 10160, and has no branch in Nonthaburi, but jobs there can be arranged by phone at 065-556-6294 or LINE @whd268. Same-day service is not guaranteed.

Germs That Road Floodwater Carries Into Lak Si Buildings

Standing water on city roads such as Ngam Wong Wan or Vibhavadi Rangsit is water that has backed up from drains and mixed with building wastewater, rubbish, oil and animal waste. When it flows into shophouses, car parks and lobbies it leaves germs on surfaces. The World Health Organization (WHO), the US CDC and Thailand's Department of Disease Control advise cleaning flood-touched surfaces first and then disinfecting. The main germ groups are:

Bacteria from the drains

Sewage-related bacteria such as E. coli and Salmonella can cling to shop floors, steps, doormats and car tyres in parking areas. Hands that touch these and then food can lead to diarrhoea, stomach pain or vomiting.

Leptospirosis from drain rats

City drains are home to rats. When drains fill up, rats look for dry ground. Leptospira from rat urine may be present in road water and flooded car parks, so commuters who wade with cuts on their feet are at risk.

Viruses in busy shared spaces

Lak Si's condos, offices and government buildings see heavy foot traffic. Norovirus, rotavirus, influenza and RSV pass easily via lift buttons, door handles, stair rails and counters, especially when people have just come in from the water without washing their hands. Hand, foot and mouth disease is common among young children at home and in childcare.

Mould in enclosed and basement spaces

Basement car parks, under-stair storerooms, plant rooms and office carpets are often poorly ventilated and dry slowly after getting wet, so mould grows easily. CDC advises cleaning and drying within 24 to 48 hours to limit mould. Spores can trigger allergies and asthma in people who work or live in the building.

This is general, group-level information. Not every building in Lak Si will contain every germ, but it shows why cleaning and disinfection go together.

Who Is Most at Risk in Lak Si, and When to See a Doctor

• Commuters who waded along Ngam Wong Wan, Chaeng Watthana and Vibhavadi Rangsit while the roads were flooded.
• Cleaners and building technicians who wash car parks, plant rooms and lobbies.
• Young children and older people in shophouses and condos that share building entrances.
• People with allergies or asthma, who are sensitive to mould spores in damp rooms.
• Pregnant women and people with chronic illness, who should avoid wading.

See a doctor straight away for high fever with calf pain after wading, repeated diarrhoea, a foot wound that becomes red, swollen or pus-filled, a cough or breathing problem that is getting worse, or a child with fever and mouth blisters. Disinfection reduces germs on surfaces. It is not a medical treatment.

What Happens When Germs Are Left in Buildings

Occupant health: staff, customers and residents may keep falling ill with diarrhoea, allergies or respiratory symptoms, which affects whole teams.

Business: shops and offices with a musty smell make customers reluctant to stay and can lose their trust.

Property: mould in carpets, gypsum walls and wooden furniture means more replacement and higher long-term costs.

Building management: condo and office managers have to answer residents' and tenants' questions. A clear disinfection process reduces complaints.

Why Cleaning the Building Is Not Enough on Its Own

• Mopping with general cleaner makes floors look clean, but one mop used across a building can carry germs from the car park to the lift lobby.
• Bleach poured on floors that still have sediment cannot reach germs evenly, and fumes in enclosed spaces such as basements can be hazardous. Never mix it with other products.
• Air conditioning to dry things out lowers humidity but does not disinfect, and can carry spores into the air system.
• Lobby air fresheners mask odours while the cause remains in carpets and walls.
• Wiping only where the water reached misses what people touched after wading, such as lift buttons, handles and stair rails.

The approach recommended by CDC and the Department of Disease Control is to remove sediment and damaged materials, wash with clean water and detergent, dry, and then disinfect. Spraying by a trained team helps that final step cover a whole building in little time.

How the WHD Disinfection Service Works in Lak Si

According to WHD's service information, trained technicians spray and/or apply ULV (Ultra Low Volume) fine-mist fogging with 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, with examples including COVID-19, RSV, H1N1, H5N1 and hand, foot and mouth virus and a claimed 99.99% efficacy, and lists approvals or endorsements from the Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019. Customers named on the page include hospitals, schools, malls, airports, offices, airlines, banks and residential buildings.

For organisms not named on the page, such as E. coli or Leptospira, we do not claim an organism-specific test result. They belong to the bacteria group the product says it covers. Ask WHD if you need test data for a particular organism.

Steps for Lak Si shophouses, condos and offices

1. Survey: send photos and details on LINE, such as ground-floor area, car parks, number of lifts, lobbies and how high the water rose.
2. Clean first: remove sediment and damaged materials such as carpets and swollen wall panels, and finish washing before spraying day.
3. Zoning: for example shopfront, storeroom, car park, lift lobby, corridors and shared toilets, scheduled to limit disruption.
4. Temporary closure: residents, staff, customers and pets leave the zone being sprayed, and food and dishes are stored away.
5. Spraying: floors, lower walls, counters, lift buttons, handles, stair rails and toilets are treated, with fine-mist fogging where suitable.
6. Re-entry: according to the service information, wait about 30 minutes or as advised, ventilate, then reopen the area.

Do not assume spraying leaves nothing behind. Wipe food-contact surfaces as the technicians advise. If an enclosed room still smells musty, residential ozone disinfection is available as a complementary service.

According to the service information, customers receive a free CHEMGENE spray bottle and WELLGIENIC wet tissues, and a tax invoice is available. Prices depend on area and conditions, so please request a quotation.

10 Reasons Lak Si Buildings Should Disinfect After the Flood

1. The water came from the drains, not clean rain, so it carried waste and germs inside.
2. Heavy foot traffic in condos, offices and shops. A professional disinfection service treats shared touch points.
3. Basement car parks dry slowly and are prone to mould and musty smells.
4. It lowers risk for cleaning staff who work in contaminated areas every day.
5. Medical-grade disinfectant, described on the service page as covering viruses, bacteria and fungi.
6. Trained technicians work zone by zone, so the whole building does not need to close.
7. Short wait. About 30 minutes according to the service information, so businesses reopen quickly.
8. It answers tenants and customers who want to know the building has been treated properly.
9. Ready for the next rain, which the BMA expects from 10 to 13 October 2026. Book a slot in advance.
10. Tax invoice available for juristic persons, companies and shops.

Before and After Spraying in Lak Si

Example Case: A Condo Off Chaeng Watthana Road With a Flooded Car Park

This is an illustrative scenario that explains the process. It is not a real customer review.

Nid manages a condominium off Chaeng Watthana Road. In late September, road water ran down the ramp into the basement car park and seeped into the bin room and part of the plant room. When it drained away, the housekeeping team hosed the car park, removed sediment and ran fans for several days, but residents kept asking in the condo's LINE group whether anything had been disinfected.

Nid contacted WHD on LINE @whd268 with photos of the car park, bin room and lift lobby. The team suggested working zone by zone at quiet times. Management told residents in advance to avoid zones being sprayed. Technicians treated the car-park floor and lower walls, the bin room, lift buttons, fire-stair rails and entrance doors, then gave reopening times for each zone. Nid now plans to inspect the car-park walls regularly and deal with any mould that appears.

Recovery Checklist for Lak Si Buildings

Before spraying day

• Check the electrics, water pumps and building drainage after the flood.
• Give cleaning staff boots, rubber gloves and masks.
• Throw out carpets, cardboard boxes and other absorbent materials.
• Wash floors and lower walls with clean water and never mix chemicals.
• Ventilate enclosed areas until they are as dry as possible.
• Send photos of each zone to WHD on LINE @whd268.

On the day

• Tell residents or staff in advance which zones will be sprayed and when.
• Store food, dishes and any goods on open display.
• Make sure everyone, including pets, leaves the zone being sprayed.

After spraying

• Wait as advised, then ventilate.
• Wipe food-contact surfaces.
• Watch the basement for musty smells and mould over the next one to two weeks.
• See a doctor if anyone has fever, calf pain or diarrhoea.

FAQ: Disinfection Service in Lak Si

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

Can you treat a condo car park and shared areas?
Yes. The work is planned zone by zone with the juristic person so residents can keep using the building.

The water never came inside; we only waded on the road. Should we spray?
If no water entered, washing shoes and hands and cleaning the entrance may be enough. For buildings where water came in, or where many people pass through, spraying adds confidence.

How long do we stay out?
According to the service information, generally about 30 minutes after spraying, or as the technicians advise.

Do you work in Nonthaburi?
WHD has no branch in Nonthaburi, but jobs can be arranged by phone or LINE once details are confirmed.

If we spray, do we still need a doctor?
Yes, anyone with symptoms after wading should always see a doctor.

Building in Lak Si Cleaned? Let WHD Finish the Job With Disinfection

Shophouses, condos, car parks, offices or homes in Lak Si or Nonthaburi: contact WHD for an assessment and booking.

Book Disinfection in Lak Si

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, BMA alert of 26 Sep 2026: thaipbs.or.th/news/content/558579
• Thai PBS, Ngam Wong Wan and Chaeng Watthana readings: thaipbs.or.th/news/content/558585
• Thai PBS, Vibhavadi, 27 Sep 2026: thaipbs.or.th/news/content/558662
• Thai PBS, flood points, 29 Sep 2026: thaipbs.or.th/news/content/558830
• Thansettakij, 26 Sep 2026: thansettakij.com
• Manager Online, Vibhavadi, 26 Sep 2026: mgronline.com
• Siamrath, 28 Sep 2026: siamrath.co.th
• Thai Post, 3 Oct 2026: thaipost.net
• Posttoday, 15 high-impact districts: posttoday.com
• Krungthep Turakij, Nonthaburi Cell Broadcast: bangkokbiznews.com
• Matichon, Nonthaburi DDPM centre: matichon.co.th
• CDC Floods: cdc.gov/floods
• Department of Disease Control, Thailand: ddc.moph.go.th