A typical scenario (an illustrative example, not a review from a specific customer)

A Bang Nam Priao housing estate where the still water outside turned black

Nid, 45, works for a company in Bangkok and commutes by car every day. Her home is a two-storey townhouse in a housing estate in Bang Nam Priao district, Chachoengsao, which she shares with her 72-year-old mother and nine-year-old daughter. After heavy rain, the canal behind the estate overflowed and water slowly rose into the ground floor, reaching about mid-shin. Then it simply stayed. Every morning Nid had to wade out to her car, parked at the mouth of the lane.

After several days, the still water in front of the house turned dark, with foam and an oily film on the surface. A rotten smell drifted up to the second floor, worst at night when there was no breeze. Nid's mother lost her appetite and complained of dizziness. Her daughter's legs were covered in mosquito bites. Nid herself had a scrape on her shin from wading that was starting to look inflamed.

When the water finally went down, a thin layer of mud coated the ground floor. The plaster walls had a clear tide line, the plywood doors had swollen, the cabinet under the kitchen sink had collapsed, and a mixture of rotten and musty smells remained even with every window open. This is very different from a flood that comes and goes quickly. The longer water stands, the deeper materials soak, the more organic waste rots, and the more time germs have to multiply.

Chachoengsao flood 2026: all 11 districts, 47,959 households, and a Bang Pakong that cannot drain fast enough

According to the DDPM report of 2 October 2026, flooding nationwide affected 31 provinces plus Bangkok, covering 1,245,581 households and 3,535,206 people. The causes were heavy to very heavy rain combined with large volumes of water from the North.

For Chachoengsao in the eastern region, Thai PBS reported flooding in all 11 districts: Bang Nam Priao, Phanom Sarakham, Bang Khla, Tha Takiap, Sanam Chai Khet, Plaeng Yao, Mueang Chachoengsao, Ban Pho, Bang Pakong, Khlong Khuean and Ratchasan, noting that the Bang Pakong River was not draining into the sea fast enough. DDPM reported 47,959 affected households on 2 October 2026. These are snapshots from the reporting date and may change daily, so keep following provincial and DDPM announcements.

The Bang Pakong River is the lifeline of Chachoengsao, flowing through several districts before reaching the Gulf of Thailand. When the river drains slowly, the canals that feed it and the low-lying plains around them drain slowly too. The result is prolonged standing water across many areas, which makes recovery after the water recedes much harder than after a flash flood that drops quickly.

Chachoengsao has many kinds of housing: old wooden houses and shophouses along the river in Mueang and Bang Khla, housing estates and townhouses for people working in Bangkok and in industrial zones, homes among rice fields, mango orchards and fish and shrimp ponds, and communities on higher ground in the east such as Phanom Sarakham, Sanam Chai Khet and Tha Takiap. Each area may have received different amounts of water, but the principles of recovery are the same everywhere.

Why long-standing floodwater in Chachoengsao is more dangerous than it looks

Still water goes septic. When water stops moving, organic matter such as plant debris, food waste and septic overflow is broken down by microbes until the oxygen in the water runs low. The water turns black and smells of rotten eggs, and that smell soaks into plaster, wood, fabric and furniture.

Materials soak deeper. Plaster, plywood, gypsum and wooden floors that sit in water for days wick moisture well above the actual waterline and take far longer to dry.

Germs have time to multiply. Bacteria and mold in the water and in wet materials keep growing for as long as the water stands, so when it finally recedes it leaves more contamination behind than a quick flood.

Mosquitoes and other carriers. Standing water around homes, in containers and old tires is a breeding ground for mosquitoes, which carry dengue. Rats also live closer to people during floods.

Repeated daily exposure. People who must wade to work or to the market every day build up risk, especially if they have cuts on their feet and legs.

Every kind of germ that floodwater brings to Chachoengsao

Fecal and wastewater bacteria

E. coli, Salmonella and Shigella come from human and animal feces mixed into the water from overflowing septic tanks and drains. In areas with livestock farms and fish ponds, floodwater also carries farm waste. These bacteria cause diarrhea, stomach pain, vomiting and fever, spreading through hands, dishes and contaminated food.

Leptospirosis

Leptospira bacteria from rat urine can survive in water and mud for a long time, and Chachoengsao's rice fields and canal-side communities are prime rat habitat. The bacteria enter through wounds, scrapes and skin softened by long soaking. Symptoms include sudden high fever, headache, severe calf pain and red eyes. If these appear about one to two weeks after wading, see a doctor right away and mention your flood exposure.

Wound infections

Small cuts on the legs and feet of people who wade daily easily become infected with bacteria. A wound that is swollen, red, hot, full of pus or accompanied by fever needs a doctor. Do not wait.

Viruses

Norovirus and rotavirus cause diarrhea and vomiting and spread fast in families and communities sharing water and toilets. Respiratory viruses spread easily when people are crowded together. Conjunctivitis and skin conditions are also common after floods.

Mold

WHO and CDC advise cleaning and drying a home within 24 to 48 hours after floodwater recedes. In Chachoengsao homes where water stood for days, mold started growing before the water even left. It appears as black, green or fluffy white patches on lower walls, door frames, plywood cabinets, ceilings, curtains and mattresses. Spores trigger allergies, coughing, sneezing, congestion and asthma, and are more dangerous for people with weak immunity.

Musty and sewage odors

Homes that sat in stagnant water often have two layered smells: a rotten-egg stench from wastewater and mud, and a musty smell from mold. Both mean microbes are still active, and they often survive several rounds of floor washing.

At-risk groups

Elderly people, young children, pregnant women, people with diabetes whose foot wounds heal slowly and infect easily, people with kidney or heart disease, allergies or asthma, anyone with weak immunity, and workers who have to wade through water every day.

What Chachoengsao families carry after prolonged flooding

Health: allergies, respiratory problems, diarrhea, wound infections and leptospirosis risk built up over days of wading.

Money: repairs to walls, doors, kitchen cabinets, furniture and appliances cost more than after a short flood, because materials soaked for so long.

Time: walls that absorbed water deeply take a long time to dry fully, and many homes wash again and again because the smell will not leave.

Business and reputation: riverside shophouse stores, restaurants and guesthouses lose customers if sewage or musty odors linger.

Family: commuters to Bangkok have little time to look after the house, elderly relatives at home all day breathe unhealthy air, and stress builds after weeks of living with water.

Why sewage smells and mold keep returning in Chachoengsao homes after several washes

Washing only the floor. Mud and wastewater seep into the lower walls, tile grout and under skirting boards, so hosing the floor is not enough.

Too much bleach. Bleach helps on smooth surfaces but cannot reach mold threads inside plaster and wood, and strong solutions in closed rooms or mixed with other products create dangerous fumes. Follow Department of Disease Control guidance.

Running fans without waiting for real dryness. Walls that soaked for days may be dry on the surface but damp inside. Close the room again and the mold returns.

Incense, candles or perfume sprays. They mask odors briefly, but the sewage smell embedded in materials returns when the fragrance fades.

Repainting right away. The paint blisters and mold pushes back through because the wall is still wet and still contaminated.

A home that sat in standing water needs deep cleaning, removal of damaged materials, enough time to dry, and a disinfection step that covers the entire room including the air. Ozone fills that final role.

WHD ozone disinfection in Chachoengsao

World Health Disinfection (WHD) provides ozone disinfection for homes and buildings, including houses, townhouses, shophouses, condos, hotels, offices, factories, schools and hospitals. WHD is based in Bang Khae, Bangkok 10160, and has no branch in Chachoengsao. The team can plan service in the province, with travel, coverage and timing confirmed by phone at 065-556-6294 or LINE @whd268 in advance. Same-day arrival is not guaranteed.

Ozone (O3) is a gas with strong oxidizing power. It breaks down the structures of bacteria, viruses and mold spores, and it breaks apart odor molecules, including sewage and musty smells. When finished, it reverts to oxygen (O2), leaving no chemical residue. According to test results certified for the company by the Department of Medical Sciences and Intertek (UK), it eliminates viruses, bacteria and mold by 99.99%.

In Chachoengsao homes that sat in standing water, ozone gas reaches the hidden places where odors settle, such as under stairs, behind kitchen cabinets, above ceilings and in storerooms, where wiping cannot reach evenly.

How it works

1. Consult on LINE or by phone: share the water height, how long it stood, the type of home, and photos of the rooms.
2. Restore before treatment: remove mud, take out swollen or rotten materials, wash, disinfect surfaces, and dry both surface and interior of materials.
3. Prepare the room: people, pets and plants leave the zone; close doors and windows; open cupboards and drawers.
4. Ozone treatment: the zone is filled with ozone; a typical cycle is about 30 minutes per zone.
5. Rest and ventilate: the ozone breaks down, the room is aired, and only then is it used again.

Safety rule: ozone treatment happens only in a closed, empty room. People, pets and plants must be out of the area, and nobody re-enters until the rest and ventilation period the team specifies has passed.

More information: ozone cleaning service and Chemgene disinfectant.

10 reasons Chachoengsao homes should use ozone after standing floodwater

1. Tackles deep-set sewage odors. Ozone breaks odor molecules apart rather than masking them.
2. Many germs at once. Bacteria, viruses and mold at 99.99% according to the company's certified tests. See residential ozone disinfection.
3. Reaches what wiping cannot. Under stairs, behind kitchen cabinets, above ceilings and in storerooms.
4. No chemical residue. Ozone returns to oxygen, suitable for homes with elderly relatives and children.
5. Short cycles. About 30 minutes per zone, helpful for working families short on time.
6. Less mold regrowth. When done after real drying and followed by humidity control.
7. Suits riverside shophouses and stores. Helps shops reopen without odors putting customers off. More on the ozone service page.
8. Zone by zone. A two-storey townhouse can do the ground floor first, then the upper floor if needed.
9. Backed by test results. See the certificates page.
10. Worthwhile promotion. Ozone jobs of 15,000 baht or more include a free medical-grade disinfectant spray.

Before and after: a Chachoengsao townhouse ground floor after standing water

Note: results depend on removing damaged materials, washing and genuinely drying before treatment.

Example case: a wooden shophouse near the Bang Pakong River in Mueang Chachoengsao

An illustrative example to explain the process, not a real customer review.

Somchai, 53, runs a grocery store in a two-storey wooden shophouse near the Bang Pakong River in Mueang Chachoengsao. The ground floor is the shop with a stockroom behind it, and the family lives upstairs, including his 81-year-old mother, who has diabetes. When the river overflowed and drained slowly, water rose almost to knee height downstairs and stayed for a long time. The family managed to carry some stock upstairs, but the rest was ruined.

After the water receded, Somchai threw out all food stock that had touched floodwater, following hygiene advice. He removed the mud, tore out swollen plywood shelving and the vinyl floor covering, washed the wooden floor and walls with clean water and detergent, then disinfected the surfaces. He left the shopfront open with several fans running for nearly two weeks, because timber that soaks for a long time dries slowly. But the sewage smell from under the wooden floor and in the stockroom would not go away, and some regular customers walked in and quickly walked out again.

Somchai's son contacted the WHD team on LINE, sending photos of the shop and stockroom. The team suggested three zones: the shopfront, the stockroom, and his grandmother's upstairs bedroom where the smell had drifted, and arranged a date to travel to Chachoengsao on a day the shop was closed. That day the family took Grandma to stay with Somchai's sister for half a day. The team treated one zone at a time and gave the family a time to return after the rest and ventilation period.

Afterwards the sewage smell in the shop was clearly reduced and Somchai could reopen with more confidence. Even so, the team stressed that his diabetic mother should have a doctor check a small wound on her foot from helping move stock during the flood, because people with diabetes are prone to infection and heal slowly. Ozone looks after the house and shop. Health care is a doctor's job.

Chachoengsao recovery checklist for prolonged flooding

While water is still standing

• Avoid wading unless necessary. If you must, wear boots, then wash your feet with clean water and dry them straight away.
• Cover wounds on legs and feet with waterproof plasters and check them daily for inflammation.
• Turn containers upside down, cover water jars and sleep under a mosquito net.
• Drink clean water and eat freshly cooked food.

Once the water recedes

• Switch off power at the breaker and have an electrician check wiring and appliances before use.
• Remove all mud, including under stairs, under cabinets and from drainage channels.
• Take out materials that soaked until they swelled, rotted or grew mold, such as plywood cabinets, gypsum ceilings, mattresses and rugs.
• Wash floors and walls with clean water and detergent, scrub tile grout and skirting, then disinfect surfaces according to Department of Disease Control guidance.
• Ventilate long enough. Walls that soaked for days may need many days or longer to dry inside.
• Have the septic tank emptied, or contact the local authority if your home's wastewater system was damaged.

Treatment day

• People, pets and plants leave the zones being treated.
• Open cupboards and drawers; close doors and windows.
• Return only after the rest and ventilation period.

After ozone

• Ventilate daily and control humidity.
• Repair leaks and seepage points.
• Watch everyone's health. Fever, calf pain, diarrhea, an inflamed wound or breathing difficulty means see a doctor at once.

FAQ: ozone disinfection in Chachoengsao after flooding

1. Can WHD serve Bang Nam Priao, Bang Pakong or Phanom Sarakham?

WHD is based in Bang Khae, Bangkok, with no branch in Chachoengsao, but can plan service in the province. Travel and coverage are confirmed by phone at 065-556-6294 or LINE @whd268.

2. The water stood a long time. How long should we wait before ozone?

Until walls and floors are truly dry, not just dry on the surface. The time depends on materials and weather. The team can help assess from your photos and details.

3. Will the sewage smell disappear completely?

Ozone is effective at breaking down odor molecules, but if mud or rotting materials remain, the smell will come back. Remove mud and damaged materials first.

4. Can we stay upstairs during treatment?

It depends on whether the upper floor can be completely sealed from the treated zone. As a rule, everyone should leave the house during treatment and ventilation. The team will advise based on your home.

5. Can a shophouse store use the service?

Yes. Book on a day the shop is closed, and the space must be empty during treatment. Any food stock that touched floodwater must be discarded first.

6. I have an inflamed foot wound after wading. What should I do?

See a doctor, especially if you have diabetes, and go immediately if you also have fever or calf pain. Ozone is not a treatment.

7. Is there a promotion?

Ozone jobs worth 15,000 baht or more receive a free medical-grade disinfectant spray.

Talk to WHD about ozone disinfection in Chachoengsao

Send photos of your home or shop after the water recedes on LINE. The team will assess, define zones and plan travel to Chachoengsao with you.

See the Ozone Disinfection Service

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

Related services

• Residential and building ozone disinfection
• Ozone cleaning service
• Ozone and chemical residue reduction
• Contact us

References

• Thai PBS, Chachoengsao flood report: thaipbs.or.th/news/content/558960
• Bangkokbiznews, DDPM flood situation: bangkokbiznews.com/news/news-update/1254629
• CDC Floods: cdc.gov/floods
• WHO fact sheets: who.int/news-room/fact-sheets
• Department of Disease Control, Thailand: ddc.moph.go.th