A typical scenario from an old canal-side market (example case)

Auntie Muay sells curry over rice from the front of a wooden shophouse her father rented back when boats were still the main way to get around Ongkharak. Downstairs is the shop: a food cabinet, a charcoal stove, four wooden tables and a tiny bathroom at the back by the canal. Upstairs is where she sleeps, along with her mother, who is in her eighties and finds the steep wooden staircase harder each year.

The night the water reached the market, she and her neighbours stacked sandbags across the shopfront. But the water did not only come from the front. It welled up through the bathroom drain, flowed in from the canal side and crept under wooden doors that never quite sealed. Before long the sandbags made no difference. The water reached her knees at the front and was deeper at the back. The bathroom was unusable. Every day she had to find a way for her mother to use a toilet, though her mother could not manage the stairs alone. Relatives who wanted to help could not reach them, because every lane in the market had turned into a waterway.

Eight days later the water receded. A thin film of mud coated everything. Drain and musty smells drifted up to the bedrooms. The table legs and floorboards carried a straight tide line at exactly the water's height. She wanted to reopen as soon as possible, with almost two weeks of lost income behind her, but she was not sure the kitchen and shop were clean enough to cook and sell food from. Auntie Muay is a composite character, not a real person, but her situation mirrors what was reported at Ongkharak Old Market this year.

Where the water was at Ongkharak Old Market, and the Nakhon Nayok picture

News1live reported the following about Ongkharak Old Market:

• Duration: eight consecutive days of flooding, from about 8 p.m. on 25 September 2026 to 2 October 2026.
• Depth: roughly knee-deep in front of the shops, deeper along the canal.
• How the water got in: through several routes, not only the front; sandbags could not hold it.
• Sanitation: toilets could not be used.
• Vulnerable people: older residents and children had difficulty getting help.

At province level, Thai PBS reported on 30 September 2026 that Nakhon Nayok had 4 districts, 41 subdistricts and 397 villages affected, a total of 28,028 households, and news reports in the same period noted water being released from the Khun Dan Prakan Chon Dam. These are province-wide figures, not figures for the market itself, and they change daily. Follow announcements from the Ongkharak district office, the local municipality and the Nakhon Nayok provincial disaster prevention office for the latest information.

What sets Ongkharak Old Market apart is the combination of failed toilets and eight days of standing water. When sanitation breaks down, waste from toilets, drains and septic tanks mixes into the water that sits inside shops and homes. That is the main risk to deal with first once the water is gone.

Where moisture and germs hide in Ongkharak's wooden shophouses

Old riverside shophouses have a charm that is hard to find today, but their construction offers plenty of places for germs and damp to hide:

• Ground-floor floorboards and beams. After days of soaking, moisture penetrates deep into the timber. The surface dries quickly; the inside stays wet.
• Folding wooden shopfront doors. Their grooves and hinges trap mud and waste.
• Shared timber party walls. Adjacent units share walls, so damp and odour move from one shop to the next.
• The bathroom at the back on the canal side. The deepest water and the most backed-up waste.
• Kitchens and food cabinets. For food stalls, any surface that touches food needs extra care.
• Under the stairs and the void between the upper floor and the ground-floor ceiling. Moisture rises and collects, so the upstairs bedrooms smell musty even though the water never reached them.
• Stock and ingredients. Rice sacks, cardboard boxes, fabric and dry goods that got wet become food for mold.

Every kind of germ the flood left at Ongkharak Old Market

Sewage bacteria: E. coli and Salmonella

With toilets out of action and drains overflowing, E. coli and Salmonella from faeces end up in the water standing in shops and homes, and settle on floors, counters, containers and cookware. For food vendors this is the single biggest risk, because these bacteria cause food poisoning, diarrhoea, stomach pain, vomiting and fever, both in the family and in customers.

Leptospirosis risk

Markets with food scraps attract rats. Their urine, mixed into water that stood for eight days, raises the risk of Leptospira infection, which enters through cuts and skin softened by soaking. Vendors who waded knee-deep every day to check on their shops or move stock should watch for sudden high fever, headache and severe calf pain, and see a doctor promptly if they appear, mentioning the flood exposure.

Stomach and respiratory viruses

Norovirus and rotavirus spread easily through hands and surfaces contaminated by sewage, especially when toilets are out and clean water for handwashing is scarce. RSV and influenza spread well when several families crowd into stuffy upstairs rooms. The young children and older residents who struggled to reach help during the flood need the closest watching now.

Mold on timber, stock and walls

Eight days of soaked timber plus the humid tail of the rainy season make it easy for mold to grow on floorboards, table legs, folding doors, cardboard boxes and fabric. Spores cause allergies, sneezing, itchy eyes, coughing and asthma flare-ups. The WHO and the US CDC advise cleaning and drying within 24 to 48 hours. When water stays for eight days, that window is long gone, and mold is usually deeper than it looks.

Drain and musty odours

The smell in the market after the water drops has two sources: sewage and rotting mud trapped in floor gaps and drains, and musty compounds from mold in the wood. For a market shop, smell is what a customer notices before seeing the goods, and it is the reason they walk on by.

Older residents and children: the people to look after first

Reports from Ongkharak Old Market specifically noted that older people and children found it hard to get help during the flood. After the water drops, they remain the most vulnerable to germs left in the home.

• Older people living upstairs. Many struggle with steep wooden stairs and may have held on or drunk less while toilets were unusable, raising the risk of dehydration and urinary infection. They should have a health check after the flood.
• Young children, who play on shop floors, put things in their mouths and dehydrate quickly with diarrhoea.
• Pregnant women, who should avoid wading and cleaning contaminated bathrooms.
• People with chronic illness, such as diabetes, high blood pressure, kidney or lung disease, and anyone with foot wounds.
• Vendors who waded every day, at higher risk of leptospirosis and infected wounds.

What the flood costs Ongkharak Old Market once the water is gone

Lost income. Eight days closed, plus several more days of cleaning. For small shops that live day to day, that is income gone entirely, and the longer the shutters stay down, the more regulars drift to other sellers.

Stock and ingredients. Dry goods, rice, cardboard, clothing and anything contaminated by floodwater must be thrown away. Do not be tempted to sell it.

Customer confidence. Customers who know the market just flooded watch for cleanliness closely. One whiff of drains or mustiness in a food shop can stop them coming back.

Family health. The shop is the home. If the ground floor still harbours germs, the people sleeping upstairs breathe the smell and spores every night.

Community heritage. The old wooden shophouses are the market's identity. If mold and damp eat into the timber, buildings that have stood for decades could deteriorate faster than they should.

Why a rushed market clean-up is not enough

• Hosing out the mud and reopening. The mud goes, but sewage germs remain in floor gaps, table legs and under counters.
• Splashing bleach everywhere. It disinfects surfaces it touches but does not soak evenly into timber, and the fumes in poorly ventilated shophouses sting eyes and noses. Never mix it with toilet cleaner or ammonia.
• Fans to dry things out. If moldy items are still inside, fans blow spores up to the bedrooms.
• Incense, perfume or kaffir limes. They mask the smell for a while; the germs stay put.
• Cleaning only your own unit. Shophouses share walls and lanes. If next door still has mud and germs, the smell travels back and forth.

Cleaning always comes first. But a market where the toilets failed and water stood for eight days needs an extra step, one that deals with germs and odour in the air, in the timber and in the gaps no cloth can reach.

WHD's ozone disinfection for shops and homes at Ongkharak Old Market

World Health Disinfection (WHD) is based in Bang Khae, Bangkok, and has no branch in Ongkharak or anywhere in Nakhon Nayok province. The team can take your request and plan a visit to the old market, with travel, route and date confirmed in advance by phone (065-556-6294) or LINE (@whd268). We do not promise same-day access.

Our residential and building ozone disinfection service uses ozone gas (O3), a strong oxidiser that breaks down the cell structures of viruses, bacteria and mold and reacts with odour molecules. It then reverts to oxygen (O2), leaving no chemical residue on counters, cookware or bedding, which matters a great deal for food businesses. According to test results certified for the company by Thailand's Department of Medical Sciences and Intertek (UK), it eliminates viruses, bacteria and mold by 99.99%.

For a shophouse with a shop below and bedrooms above, the team can divide the building into zones, such as the shopfront, the kitchen with the back bathroom, and the upstairs rooms, and treat them one by one. When several neighbours in the same row are treated together, it also cuts down odour moving through shared walls.

How the job runs

1. Get in touch and send photos of the shopfront, kitchen, bathroom, upstairs rooms and floor area via LINE.
2. Assessment and scheduling: the team checks the route into Ongkharak and whether the site is ready.
3. Clean and dry first: mud out, bathroom and kitchen washed, contaminated stock and ingredients discarded, rooms ventilated.
4. Clear the building: people, pets and plants out, folding doors and windows closed.
5. Zone-by-zone ozone treatment: typically about 30 minutes per zone, depending on size and condition.
6. Rest and ventilation: the ozone breaks down, the building is aired, and occupants return when the team says so.

Safety rule. Ozone treatment takes place in a closed space with no people, pets or plants inside. Older relatives who live upstairs must stay elsewhere temporarily on the day and return only after the rest and ventilation period. Ozone follows mud removal, washing and drying. It does not replace bathroom cleaning, plumbing repairs or medical care. Anyone with fever, diarrhoea or calf pain after wading must see a doctor.

10 reasons Ongkharak market shops should consider ozone before reopening

1. Failed toilets spread sewage germs through the whole shop, so disinfection needs to go beyond mopping.
2. Eight days of standing water is far beyond the 48-hour window; mold is already deep in the timber.
3. No chemicals left on food-contact surfaces. Ozone breaks down into oxygen. Details on the ozone service page.
4. It removes the odour customers notice first, both drains and mustiness.
5. It covers the shop and the bedrooms above, zoned to fit the shophouse layout.
6. It reaches timber gaps, folding doors and under the stairs, where cloths do not.
7. Certified 99.99% according to test results certified for the company by the Department of Medical Sciences and Intertek.
8. Short treatment time: about 30 minutes per zone, helping you reopen on schedule.
9. Whole rows can be treated together, reducing odour passing through shared walls. See the service scope for buildings and shops.
10. Combine jobs for better value. Ozone jobs of 15,000 baht or more include a free medical-grade disinfectant spray for tables and counters.

Before and after: a canal-side wooden shophouse at Ongkharak Old Market

Note: results depend on removing sewage residue and drying before treatment. Damaged pipes or septic tanks must be repaired first.

Example case: a traditional coffee shop in a wooden shophouse

This example case is an illustrative scenario based on common job types. It is not a review or quotation from a real customer.

Tom took over his grandfather's traditional coffee shop, which occupies two adjoining two-storey wooden shophouse units backing onto the canal. Tom, his wife, their primary-school-age son and his grandmother live upstairs. During the eight-day flood, the family managed to move his grandmother to relatives outside the market on the third day, after waiting half a day for a volunteer boat.

When the water went down, Tom and his neighbours shovelled the mud out of the shop, scrubbed the bathroom several times with detergent, threw away bags of coffee beans, dented cans of condensed milk and wet sugar, scrubbed the marble tables and wooden chairs, and left the folding doors open for three days. Yet the shop still smelled faintly of drains every morning, and the upstairs bedroom was so musty his son refused to sleep there.

Tom contacted WHD on LINE. The team asked for photos and room sizes, confirmed that the market lanes were dry enough to carry equipment in, and set a date. On the day, the family stayed with relatives. The team treated three zones, the shopfront, the kitchen with the back bathroom, and the upstairs rooms, one at a time with rest and ventilation periods, before telling the family they could return. In this example the drain smell in the shop and the mustiness upstairs dropped markedly, and Tom reopened that same week. The team suggested taking his grandmother for a check-up, since she had gone days drinking little with no easy access to a toilet.

Checklist for reopening a shop at Ongkharak Old Market

Safety first

• Switch off power at the main before entering. Have an electrician check sockets, fridges, freezers and appliances that were submerged.
• Check gas cylinders and hoses in the kitchen for leaks or damage.
• Wear boots, rubber gloves and a mask, and cover any cuts.
• Watch for snakes and other animals sheltering under the floor or at the canal side.

Sewage and bathrooms

• Clean the bathroom, toilet and drains before anything else, wearing protection throughout.
• If the toilet or septic tank still does not work, have it inspected and do not use it until repaired.
• Wash hands with soap and clean water after touching anything that was in floodwater.

Kitchen and stock

• Discard food, ingredients and goods that touched floodwater, including dented or swollen cans.
• Wash dishes, chopping boards and cookware in clean water, then disinfect following Department of Health guidance.
• Cook with clean or boiled water until you are confident in the tap supply.

Drying and ozone

• Open folding doors and windows for several days. Use fans only after moldy items are out.
• On treatment day, everyone, including older relatives upstairs, plus pets and plants, must leave the building.
• Return only when the team confirms the rest and ventilation period is over.
• Watch the family's health; fever, calf pain, diarrhoea or a persistent cough means seeing a doctor.

FAQ: ozone disinfection after the Ongkharak Old Market flood

Does WHD have a branch in Ongkharak or Nakhon Nayok?

No. WHD is based in Bang Khae, Bangkok. The team can plan a trip to serve the market, with the route and date confirmed first by phone (065-556-6294) or LINE (@whd268). Same-day access is not guaranteed.

Can a food shop start cooking straight after ozone?

You can re-enter after the rest and ventilation period the team specifies. Before selling food, you still need to wash utensils, discard contaminated ingredients and use clean water in line with food hygiene guidance. Ozone is an extra step, not a substitute for washing.

The bathroom still smells. Will ozone help?

It helps with odour and germs in the air, but if the smell comes from a broken pipe, a full septic tank or damaged plumbing, fix the cause first or the smell will return.

Can several shophouses be treated at once?

Yes, and it is recommended for units that share walls. Every unit being treated must be empty of people, pets and plants. Contact the team to plan a group job.

How long must older relatives upstairs stay out?

About 30 minutes per zone plus rest and ventilation. Total time depends on the number of zones. The team will tell you in advance so the family can arrange somewhere to stay.

After ozone, can we skip a health check?

No. Ozone looks after the building, not the people. Anyone who waded or has fever, diarrhoea, calf pain or a cough should see a doctor.

Bring Ongkharak Old Market back to life

Clear the sewage, dry everything out, then finish with ozone disinfection. Talk to WHD to plan service for shops and homes in the market.

See the Ozone Disinfection Service

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

Related links and references

• Residential and building ozone disinfection
• Chemgene disinfectant
• Ozone cleaning service
• Contact WHD

References

• News1live, Ongkharak Old Market flooding 25 Sep to 2 Oct 2026: news1live.com
• Thai PBS flood coverage, Sep to Oct 2026: thaipbs.or.th
• Khaosod English, 29 Sep 2026: khaosodenglish.com
• US CDC Floods: cdc.gov/floods; WHO fact sheets: who.int

Flood figures change daily. Please check the latest official announcements.