Hepatitis A After a Flood: The Slow-Arriving Threat from Contaminated Water and Surfaces, and How to Restore Your Kitchen and Bathroom with Ozone

The water went down three weeks ago and life is back to normal. Then one day the man of the house loses his appetite, feels nauseous and a little feverish. It seems like an ordinary cold, until his urine turns the colour of strong tea and the whites of his eyes turn yellow. Doctors in flood-hit areas know this picture well. The hepatitis A virus has a long incubation period of several weeks, so symptoms often appear just when everyone believes the crisis is over. The virus spreads through water, food, hands and surfaces contaminated with faeces, which floodwater carries straight into homes. This guide explains what hepatitis A is, why it survives so well in the environment, who is most at risk, and how to restore kitchens, bathrooms and household surfaces systematically, with ozone disinfection as a supporting step after washing and drying.

A Typical Scenario: A Curry-and-Rice Shop Family in Sukhothai, and Yellow Eyes Nearly a Month After the Flood

Daeng's family runs a small curry-and-rice shop on the ground floor of a two-storey shophouse beside the Yom River in Mueang Sukhothai. Downstairs is the kitchen and shopfront; upstairs is where five family members sleep: Daeng, her husband, two primary-school children and her mother. The year the Yom overflowed, water poured into the shop above knee height, flooding the kitchen, the bathroom and the septic tank behind the house. The water stank and was murky black, mixed with mud and sewage from toilets across the neighbourhood.

During the flood the family lived upstairs. With the mains water off, they used water from a large storage jar that floodwater had lapped at the rim of, for washing their faces and brushing their teeth, and sometimes for rinsing vegetables and dishes. Once the water receded, everyone pitched in to scrub the shop, hose down the floor, wipe the tables and wash the pots, then reopened quickly because they had gone more than two weeks without income.

Four weeks later Daeng's husband became unusually tired. He lost his appetite, felt sick, ran a low fever and had a dull ache under his right ribs. At first everyone put it down to overwork, until Daeng noticed the whites of his eyes had turned yellow and his urine was as dark as tea. After a blood test, the hospital doctor diagnosed hepatitis A. He advised him to stop cooking food for sale for the time being and gave the family advice on handwashing, keeping bathroom use separate and asking about vaccination for those not yet infected.

Stories like this can happen anywhere that floodwater mixes with sewage, whether in Ayutthaya, Pathum Thani, Nonthaburi, Ubon Ratchathani or Hat Yai. They are especially concerning in homes that double as food businesses, because the virus from one person can reach the whole family and the customers too.

Understanding Hepatitis A: A Tough Virus That Arrives Quietly

Hepatitis A is a virus that causes acute inflammation of the liver. It spreads by what is called the faecal-oral route: virus shed in an infected person's stool contaminates water, food, hands or surfaces, and someone else then swallows it. The World Health Organization notes that the virus is most common where sanitation and safe water are inadequate, which is exactly the situation that temporarily develops in every flood zone.

Why floods increase the risk

• Overflowing toilets and septic tanks. Floodwater forces sewage out of septic tanks and drains and carries it into every corner of the house.
• Contaminated drinking and household water. Storage jars, water tanks, shallow wells and cracked water pipes can all take in floodwater.
• Kitchens and utensils exposed to floodwater. Pots, bowls, chopping boards, cutlery and dining tables that were submerged remain contaminated if washed with unsafe water.
• Handwashing becomes difficult. During floods, clean water and soap run short and many people crowd into small spaces.
• Contaminated produce and food. Food touched by floodwater or rinsed in contaminated water and then eaten raw.

How hardy the virus is in the environment

Hepatitis A is a non-enveloped virus, meaning it lacks the fatty outer coat many viruses have, so it withstands environmental conditions better than many other viruses. It can survive on surfaces and in water for long periods and is more resistant than enveloped viruses to some common cleaning agents, such as alcohol. That is why wiping with alcohol gel alone is not enough. Washing with soap and clean water to physically remove dirt, followed by appropriate disinfection, is essential.

Symptoms

The incubation period for hepatitis A is generally about two to six weeks. Common symptoms include:

• Tiredness, loss of appetite, nausea and vomiting
• Low fever and body aches, similar to a cold
• Pain or discomfort under the right ribs
• Dark, tea-coloured urine
• Pale stools
• Yellowing of the eyes and skin (jaundice), sometimes with itching

Many young children are infected with few or no symptoms yet can still pass the virus to adults at home, while adults and older people usually have clearer and more severe symptoms. Most people recover on their own, but recovery can take weeks to months. People are most infectious in the period before jaundice appears, when they do not yet know they are ill.

Who is most at risk

• Older adults, who are more likely to become seriously ill
• People with existing chronic liver disease, such as hepatitis B or C, fatty liver or cirrhosis
• Pregnant women, who should see a doctor if they notice unusual symptoms
• People with weakened immunity and those with chronic illnesses
• Food handlers, whether cooking at home or selling food, who can infect many people if they become ill
• Children, who may have no symptoms but spread the virus and often wash their hands poorly

Anyone with yellow eyes or skin, dark urine, heavy vomiting or drowsiness must see a doctor immediately. If someone waded through floodwater and later developed fever or calf pain, tell the doctor, because leptospirosis is possible. Severe diarrhoea needs oral rehydration salts and prompt treatment. A hepatitis A vaccine is available; ask your doctor which family members it is suitable for. Ozone treatment reduces microbes in the environment; it is not a treatment and does not replace vaccination.

How Hepatitis A Affects Families After a Flood

Health

Although most people recover on their own, the fatigue after hepatitis can last a long time, keeping people from work or school. In older adults and people with existing liver disease, the illness can be severe enough to require hospital care.

Income

A patient who has to stop work for several weeks means lost income. For families who sell food, having to close the shop or stop cooking for customers is a second blow after already closing during the flood.

Time and spread within the home

Because the incubation period is long, family members may fall ill one after another, weeks apart. The household can live with worry for a long stretch, caring for the sick while watching everyone else for symptoms.

Reputation

For homes that run a restaurant, dessert shop or lunch-box business, news that someone in the shop has hepatitis can seriously damage customer confidence. Showing that the premises have been restored according to proper hygiene standards matters a great deal.

Peace of mind

Fear of catching the virus from shared cutlery, plates or the bathroom can make the atmosphere at home tense. A clear cleaning plan reduces both the real risk and everyone's anxiety.

Why Rushed Cleaning Is Not Enough Against Hepatitis A

1. Hosing the floor and nothing more. A strong jet shifts mud, but without detergent and scrubbing, a thin contaminated film stays in tile grout and on table legs.
2. Using alcohol gel instead of handwashing. Alcohol is less effective against hepatitis A than against many other viruses, so washing hands with soap and clean water remains the main defence.
3. Washing dishes with water from a flooded storage jar. This simply coats the virus back onto plates and bowls.
4. Forgetting high-touch points. Door handles, taps, toilet flush buttons, light switches, stair rails, remote controls and fridge handles are where virus from an infected person's hands ends up.
5. Using stronger chemicals than needed in the kitchen. Residues on counters and utensils can end up in food, and harsh smells make the kitchen unusable.
6. Keeping old hand towels, sponges and wooden chopping boards. These porous items trap moisture and microbes.
7. Reopening the shop or cooking for others immediately, before the kitchen is truly clean and before the cook is sure they have no symptoms.

Preventing hepatitis A after a flood therefore needs several layers: safe water, handwashing, clean utensils, cleaned surfaces and an extra round of disinfection in high-risk rooms such as the kitchen and bathroom.

World Health Disinfection's Ozone Service: An Extra Layer of Disinfection for Kitchens and Bathrooms After a Flood

Ozone (O3) is a powerful oxidiser. Released into a sealed, unoccupied room, it spreads through the air, across surfaces and into corners that cloths miss, such as under the sink, behind food cupboards, under counters, inside drawers and around the toilet. Ozone breaks down the structures of viruses, bacteria and mold and breaks apart sewage odour molecules, then reverts to oxygen (O2), leaving no chemical residue on counters or utensils that touch food.

According to the test results certified for the company by Thailand's Department of Medical Sciences and Intertek (UK), WHD's ozone system eliminates viruses, bacteria and mold by up to 99.99%. See our certification page for details.

Important: ozone treatment does not make drinking water safe, and it does not replace handwashing with soap, washing utensils, scrubbing surfaces soiled by mud and sewage, or vaccination as advised by a doctor. Ozone comes after mud removal, washing and drying. It must be done in an empty room with no people, pets or plants, and you may re-enter only after the rest and ventilation period.

How the process works

1. Survey. Our team inspects the kitchen, bathrooms, dining area and anywhere sewage-laden water reached, then divides the property into zones and sets the order.
2. Preparation. Everyone, including pets and plants, leaves the area. Fresh and opened food is removed. Food cupboards, drawers and under-sink doors are opened, and doors and windows are closed.
3. Ozone release into the sealed, empty room.
4. Contact time. The concentration is held for the set period; a typical cycle is about 30 minutes per zone.
5. Rest and ventilation. Ozone is allowed to revert to oxygen and the room is aired before anyone returns.
6. Handover, with advice on keeping high-touch points clean in the weeks ahead.

Learn more on our residential and building ozone disinfection page, and for routine wiping of high-touch surfaces see our Chemgene products.

Promotion: receive a free medical-grade disinfectant spray with any ozone job of 15,000 baht or more.

10 Reasons Homes Flooded with Sewage-Contaminated Water Should Ozone-Treat the Kitchen and Bathroom

1. An extra disinfection layer in high-risk rooms. The kitchen and bathroom are where faecal contamination and food meet.
2. It reaches under the sink, inside cupboards and behind the toilet, places hands cannot reach and people often overlook.
3. No chemical residue on food preparation areas. Ozone reverts to oxygen. Read more about removing chemical residue with ozone.
4. It removes sewage odours absorbed into the room rather than covering them with perfume.
5. It treats all the high-touch points in a room at once, from handles and taps to switches and the outside of the fridge.
6. Ideal for homes that double as food businesses, as part of preparing the kitchen before reopening. See our ozone service for homes and buildings.
7. Backed by test results. According to the test results certified for the company by the Department of Medical Sciences and Intertek, it eliminates viruses, bacteria and mold by up to 99.99%.
8. Quick. About 30 minutes per zone, so you can get back into the kitchen soon.
9. Systematic zoning by our team, covering bathroom, kitchen and dining area so no high-risk spot is missed.
10. Confidence for your family and your customers that the home has been restored hygienically. Book the WHD team.

Before and After: A Kitchen and Bathroom Flooded with Sewage-Contaminated Water

Example Case: A Home-Based Dessert Shop in Hat Yai Getting Ready to Reopen

This example case is an illustrative scenario based on commonly seen problems, used to explain the process. It is not a review from any specific customer.

Fon runs a Thai dessert stall at the front of her home in Hat Yai, Songkhla. She got in touch about two weeks after the water went down. The floodwater that entered her house contained sewage because the drains in her lane had overflowed. Her dessert kitchen is on the ground floor next to the bathroom, and a neighbour in the same lane had developed hepatitis A after the flood. Fon wanted to be confident before reopening.

Our team advised starting with a septic pumping service and a plumber to check the pipes. She threw out every ingredient and dessert the floodwater had touched, along with her wooden chopping boards, muslin cloths and old sponges. Counters, cupboards and floors were scrubbed with detergent; stainless-steel utensils and pots were washed in clean water and then disinfected appropriately; the water tank was cleaned; and exhaust fans and a dehumidifier ran until the kitchen was completely dry. Fon also talked to a doctor at her local hospital about vaccination for herself and her shop assistant.

Once everything was ready, the WHD team ozone-treated the kitchen, bathroom and shopfront in three zones while the family stayed out of the house for the whole cycle. After the rest and ventilation period the team handed the space back. Fon said what she liked most was that the kitchen had neither a drain smell nor a harsh chemical smell that might cling to her desserts. She put up a small sign at the front telling customers the shop had been cleaned and disinfected after the flood.

Checklist: Preventing Hepatitis A at Home After a Flood

Water and food

• Drink boiled water or sealed bottled water until local authorities confirm tap water is safe.
• Use safe water to wash fruit, vegetables and utensils and to brush teeth.
• Throw away food, ingredients and condiments that floodwater touched, even if the packaging looks fine, unless they are sealed, undamaged cans.
• Cook food thoroughly and avoid raw food and raw seafood for now.
• Clean and disinfect any water tank or storage jar that floodwater entered.

Hands and surfaces

• Wash hands with soap and clean water after using the toilet, after changing nappies, before preparing food and before eating.
• Scrub floors, lower walls, counters and tables that touched floodwater with detergent, then disinfect.
• Wipe high-touch points regularly: handles, taps, flush buttons and light switches.
• Throw out sponges, hand towels, wooden chopping boards and other porous items that were submerged.
• Check the septic tank and drains, and have sewage pumped out if they overflowed.

Before and during ozone treatment

• Treat only after cleaning and drying are complete.
• Remove fresh and opened food from the room.
• All people, pets and plants must be out of the area, with doors and windows closed.
• Do not enter until the team confirms the rest and ventilation period is over.

After ozone treatment and health follow-up

• Ventilate as advised, then rinse utensils in clean water again before use.
• Watch for loss of appetite, nausea, dark urine and yellow eyes during the two to six weeks after the flood.
• If someone at home is ill, keep their towels and cutlery separate and clean the bathroom more often.
• Anyone with symptoms should not cook for others until a doctor says it is safe.
• Ask a doctor about vaccination for household members.

Frequently Asked Questions

1. Is hepatitis A airborne?

No. Hepatitis A is spread by swallowing the virus, through water, food, hands or objects contaminated with an infected person's faeces. Safe water, safe food and handwashing are at the heart of prevention.

2. After ozone treatment, can we drink water from the storage jar?

No. Ozone treatment of a room disinfects the air and room surfaces; it does not treat drinking water. Drink boiled or bottled water, and clean the jar or tank before refilling it with safe water.

3. Someone at home has hepatitis A. When should we do ozone treatment?

Follow the doctor's advice on caring for the patient first. Ozone treatment can be done after cleaning the bathroom and areas the patient uses, with everyone, including the patient, out of the area during treatment.

4. What should we do with food and utensils in the kitchen during treatment?

Remove fresh and opened food. Clean utensils can stay in open cupboards; rinse them again in clean water before use. Our team will advise on site.

5. How long do we need to be out of the house?

A cycle takes about 30 minutes per zone, plus the rest and ventilation period before re-entry. The team will tell you the total time before starting.

6. If we are vaccinated against hepatitis A, do we still need thorough cleaning?

Yes. Sewage-contaminated floodwater also brings other germs, such as bacteria that cause diarrhoea. Complete restoration reduces the risk from all of them. Ask your doctor who should be vaccinated.

7. What should a home-based food business do before reopening?

Discard flood-exposed ingredients, use safe water, clean and disinfect the kitchen, utensils and equipment, check the health of food handlers, and follow local public health guidance. Ozone is a supporting step after all of this cleaning.

A Clean Kitchen, a Safe Bathroom, a Family at Ease

Talk to the WHD team about ozone treatment for your kitchen, bathroom and other high-risk areas after sewage-contaminated flooding, with no chemical residue on food preparation surfaces.

Book Post-Flood Ozone Disinfection

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

Related Services

• Residential and building ozone disinfection
• Removing chemical residue with ozone
• Chemgene disinfectant products
• Contact World Health Disinfection

References

• World Health Organization fact sheets: Hepatitis A
• Department of Disease Control, Ministry of Public Health, Thailand