A Story from the Field: Nattapon's List of Questions

Nattapon lives in a two-storey townhouse in Bang Phut subdistrict, Mueang Pathum Thani, not far from the Chao Phraya River. During the 2026 floods, water rose almost to knee height inside the house and stayed for more than ten days. The family moved in with relatives in Khlong Luang while they waited. When the water finally receded and they unlocked the front door, a wave of musty air mixed with drain smell rolled out so strongly that their seven-year-old daughter pinched her nose and said she did not want to go inside.

Over the next week they shoveled out mud, scrubbed floors and threw away several pieces of swollen furniture. The smell did not go anywhere. Black mold spots began to appear on the downstairs walls. The wooden wardrobe developed a sour, rancid odor. Nattapon's mother-in-law, who has allergies, started coughing every night. Nattapon began reading about ozone treatment, but the more he read, the more questions he had. How many hours would the family need to leave the house? Was it dangerous for his daughter, or for the family cat? Would the television and refrigerator be damaged? Should they also have the house disinfected, and if so, which should come first?

These are exactly the questions the World Health Disinfection team hears again and again from families in Mueang Pathum Thani, Bang Phut, Ban Klang, Bang Kadi and Bang Luang as the water goes down. So we have gathered the answers into one place, written in plain language, so you can make a confident decision before you book.

Please note: this article is general information. Actual timings and details depend on the size of your home, the extent of the damage and the team's on-site assessment. If someone in your household has a respiratory condition, please also seek advice from a doctor.

Why a Post-Flood Home Needs Germs, Mold and Odor Dealt With Together

Floodwater in urban Pathum Thani rarely stays clean. It mixes with water from storm drains, septic tanks and household waste. When it recedes, it leaves a layer of mud and residue on floors, walls and furniture that may contain bacteria such as E. coli, as well as the organisms that cause leptospirosis. At the same time, moisture trapped inside concrete walls, timber, ceiling boards, mattresses and curtains gives mold perfect conditions to grow, often within a few days.

• Health. The risks include diarrhea, skin inflammation, infected cuts, leptospirosis, and allergies or asthma made worse by mold spores. Children, older people and anyone with an underlying condition are the most vulnerable.
• Cost. If mold is allowed to spread, more furniture, mattresses and fabrics may need to be thrown out, and sections of wall or ceiling may need to be replaced.
• Time and wellbeing. Living in a house that still smells damp makes it hard to rest, adds to stress, and slows down the family's return to normal life.

Because the problem has three parts, germs on surfaces, mold in materials and air, and odor, a single quick fix rarely solves it. That is why so many of the questions below come back to the idea of combining methods in the right order.

Fixes That Usually Disappoint When Used Alone

Pouring bleach everywhere. Bleach can help on some hard surfaces, but the chlorine smell is harsh and irritating, and it does not reach into timber, mattresses or the cavities inside walls. It can also damage fabrics and finishes.

Leaving fans and windows open. Airflow helps things dry, which is important. But it does not disinfect anything, and if mold has already taken hold, a fan can stir up spores and spread them around the house.

Air fresheners and charcoal bags. These may reduce or cover a smell slightly for a while, but the cause of the odor is still there and the smell returns.

Repainting straight away. Paint over a damp wall will blister and peel, and mold will grow back through it. Walls need to dry completely, and contamination needs to be dealt with first.

Post-Flood Ozone Treatment: The Detailed Q&A

1. What is ozone treatment, and how does it help after a flood?

Ozone is a gas with strong oxidizing properties. When it is released into a sealed room, it spreads throughout the whole space, including corners, gaps behind furniture and cavities that a hand or cloth cannot reach. It helps deal with microorganisms and mold spores in the air, and it breaks down the molecules that cause musty, drain-like and muddy smells. That makes it a good fit for homes where odor and mold are the main complaints after the water recedes. You can read more on our ozone treatment service page.

2. How many hours does ozone treatment take?

It depends on the floor area, how strong the odor is and how many rooms need treatment. In general, each room or zone usually takes somewhere from around one hour to several hours. Larger houses with many rooms are often treated zone by zone. The team will assess your home and give you an estimated schedule on the survey day, so you can plan your day around it.

A few factors tend to lengthen the schedule: a house that is still damp, rooms full of soft furnishings such as sofas, curtains and carpets, wooden wardrobes that have absorbed odor, and spaces with poor natural ventilation that take longer to air out afterwards. Factors that shorten it include thorough mud removal beforehand, a house that has had several dry, breezy days, and rooms that have already been emptied of soaked items. If you want the day to run quickly, the best preparation is simply to clean, discard and dry as much as you can before the team arrives.

3. How long do we need to stay out of the house?

Everyone must stay out of the treated area for the whole time the machine is running, and then until the space has been ventilated sufficiently according to the team's instructions. After the machine is switched off, that ventilation period is generally at least half an hour and can be several hours, depending on room size and how well the space can be aired. Most families simply book the service for a day when they will be out running errands or visiting relatives.

4. Is it safe?

Yes, when it is done correctly. The most important rule is simple: no people, no pets and no plants inside the treatment area while ozone is being generated, and the space must be properly ventilated before anyone goes back in. High concentrations of ozone irritate the eyes, nose and lungs. After ventilation, ozone naturally breaks back down into oxygen, which is why it does not leave a chemical residue in the way some sprays can.

5. We have a small child, an elderly parent and a cat. What should we do?

Everyone, including pets, should leave the home during treatment. Aquariums and indoor plants should be moved out too. Return only after the team confirms ventilation is sufficient. For anyone with asthma or severe allergies, it is sensible to wait a little longer and keep windows open for extra airing before they settle back in.

6. Will the TV, refrigerator or computer be damaged?

The team uses a controlled dose and duration rather than running a strong concentration for longer than necessary. You will be asked to switch off and unplug electrical appliances. Ozone-sensitive electronics, artworks and collectibles with rubber components should be moved out of the room or covered thoroughly before treatment. With these precautions, everyday appliances can stay in place.

7. How is ozone treatment different from disinfection fogging?

Disinfection fogging uses a liquid disinfectant such as Chemgene HLD4H, released as a fine ULV mist that settles on surfaces like floors, walls, stair rails and door handles. It is the right tool for germs left behind by floodwater on surfaces people touch. Ozone treatment uses a gas to work on the air, on mold spores and on odors, reaching places where liquid droplets cannot fully travel. The two methods complement each other rather than compete. See our disinfection service for details.

8. Which should come first, disinfection or ozone?

The recommended order is: remove mud and clean first, let the house dry, disinfect surfaces by fogging, and then run the ozone treatment to deal with the air and odor. Finish with ventilation and a re-check. Doing it in this order means each step works on a cleaner, drier house and gives better results.

9. Is one treatment enough?

Many homes notice a clear drop in odor after the first service. However, if moisture is still building up, water is seeping through walls, or absorbent materials that were soaked are still inside, smells and mold can return. The team will reassess and advise you on which spots still need attention.

10. Can we buy an ozone machine and do it ourselves?

You can, but you need a good understanding of concentration, duration and safety. If you want a machine for ongoing use, you can look at the Master Ozone Generator and ask the team how to use it correctly first. For a house that has just been through a serious flood, using an experienced team is usually more thorough, because the team also handles surface disinfection, equipment protection and ventilation timing.

11. When should we call the team after the water goes down?

The ideal time for treatment is once the mud has been removed and the house has started to dry. If there is still standing water or a thick layer of mud, neither disinfectant nor ozone can work to its full potential. That said, you can book a site survey from the very first day the water recedes, to get advice on what to throw away, what to keep and how to prepare.

12. How should we look after the house after the service?

Open windows daily when the weather allows. Run a dehumidifier in rooms that feel stuffy. Wipe condensation from glass and bathroom walls. Repair any leaks. For the first one to two months, keep an eye out for new spots or smells, and contact the team for a reassessment if anything appears. For small everyday touch points, the Chemgene HLD4H spray is convenient to keep at home.

Five Common Myths About Ozone After a Flood

Myth 1: "Ozone replaces cleaning." It does not. Ozone cannot shovel mud, lift stains or dry a wet wall. Physical cleaning and drying always come first, and ozone works best on a house that has already been cleaned out.

Myth 2: "If a little ozone is good, more is better." Running a machine at a higher concentration or for many extra hours does not automatically give better results. It increases the risk to rubber seals, some plastics and electronics, and it lengthens the time before the family can safely return. A controlled dose matched to the room is the sensible approach.

Myth 3: "It is fine to stay in another room while the machine runs." In most homes, air moves between rooms through gaps under doors, stairwells and ceiling spaces. Unless the team confirms that an area is properly separated, everyone should leave the house during treatment.

Myth 4: "Ozone leaves a chemical residue." Ozone breaks back down into oxygen after treatment and ventilation. The faint fresh smell some people notice fades quickly once windows are open.

Myth 5: "Once treated, mold can never come back." Treatment deals with what is present at the time. If the house stays humid or water keeps seeping in, mold can grow again. Ongoing moisture control is what keeps the result lasting.

Understanding these points helps families set realistic expectations. Ozone is a powerful tool for odor and airborne mold after a flood, and it is most effective as part of a planned sequence: clean, dry, disinfect, treat, ventilate and then keep the house dry.

WHD's Service Process for Homes in Mueang Pathum Thani

1. Site survey. The team checks how high the water reached, where mold is visible, moisture levels and which electrical appliances are in each room.
2. Mud and cleaning advice. You get clear guidance on what to discard, what to keep and how long to let the house dry.
3. Disinfection fogging. A fine mist of Chemgene HLD4H is applied across floors, walls and shared touch points.
4. Dose-controlled ozone treatment. Rooms are sealed and treated zone by zone, with no people, pets or plants inside.
5. Ventilation. Doors and windows are opened for the specified time before the family returns.
6. Re-check and advice. Odor is assessed again and you receive practical advice on keeping humidity under control.

Throughout the process, the team will tell you in advance what time to leave, roughly when the treatment will finish, and when it is reasonable to return. If plans change, for example because one room turns out to be wetter than expected, they will explain the reason and adjust the schedule.

10 Reasons to Choose WHD for Ozone and Disinfection

1. Every question answered on survey day, so there is no guesswork about timing or safety.
2. Both methods in one visit: disinfection fogging and ozone treatment cover surfaces and air.
3. Controlled ozone dosing matched to room size, reducing risk to appliances.
4. Clear timings for leaving the house and for ventilation before you return.
5. ULV fogging equipment that reaches corners and the spaces under furniture.
6. A disinfectant the team uses routinely: Chemgene HLD4H.
7. Odor tackled at the source, not masked. Learn more about residential ozone disinfection.
8. Honest advice on mattresses, curtains and furniture that were soaked.
9. Careful procedures for homes with children, older people and pets.
10. Easy to contact: call 065-556-6294 or LINE @whd268, covering Mueang Pathum Thani and nearby districts.

Before and After the Service

Customer Voice (Example Scenario)

"I must have asked the team a dozen questions, from how many hours we had to be out to where the cat should stay. They answered every one and wrote the times down clearly. That day we took our daughter and the cat to my relatives' place. When we came back in the evening, the smell that used to hit us at the door was much weaker, and my mother-in-law has been sleeping better since."

Nattapon, townhouse owner in Bang Phut, Mueang Pathum Thani (example scenario)

Treatment Day: A Simple Family Checklist

Many of the questions people ask are really about the practical side of the day itself. Here is a short checklist you can follow so that everything goes smoothly.

• The night before: put food away in closed containers or the refrigerator, and gather what the family and pets will need for the day out.
• Morning: switch off and unplug appliances in the rooms to be treated. Move laptops, cameras, musical instruments, artworks and anything with delicate rubber parts out of the room, or cover them well.
• Before you leave: take children, older relatives, pets, aquariums and indoor plants out of the house. Leave keys or access arrangements with the team as agreed.
• During treatment: stay away from the house. Do not open doors to "check" while the machine is running.
• When you return: follow the team's advice on ventilation time. Open windows and run fans for extra airing, especially in bedrooms.
• The following weeks: keep humidity down, watch for new mold spots and let the team know if anything changes.

More Frequently Asked Questions

Q: Will there be a smell after the ozone treatment?
A: You may notice a faint fresh smell, a bit like the air after rain, for a short time. It fades as the house is ventilated.

Q: Do we need to put food and belongings away?
A: Yes. Store food in cupboards or sealed containers, and move plants, aquariums and pets out of the treated area.

Q: Our mattress was soaked. Can ozone make it usable again?
A: Mattresses that sat in floodwater for a long time usually hold water and dirt deep inside. In general, it is better to consider replacing them. Ozone is more suited to reducing room odor than rescuing heavily damaged mattresses.

Q: How should we prepare the house before the team arrives?
A: Remove mud and rubbish, let the house dry as much as possible, unplug appliances, and move valuables that are sensitive to ozone out of the rooms.

Q: Which areas do you cover?
A: Mueang Pathum Thani including Bang Phut, Ban Klang, Bang Kadi and Bang Luang, as well as Khlong Luang, Thanyaburi, Lat Lum Kaeo and nearby areas. Message LINE @whd268 to check your location.

Still Have a Question? Talk to Our Team

Book a site survey for your home in Mueang Pathum Thani or nearby districts. Send us a few photos of the affected rooms and let us know how high the water reached, and we can give you an idea of the steps and timing before we visit.

Book Ozone Treatment - Click Here

View Disinfection Service - Click Here

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

Related Links

• Residential ozone disinfection
• Master Ozone Generator
• Chemgene HLD4H disinfectant spray 750ml
• All articles

Health reference: World Health Organization (WHO): Floods · Department of Disease Control, Thailand