Boiling water is not enough against all kinds of contamination!

Ministry of Health Consultant Prof. Haydar Sur, warning that sewage, microorganisms, and chemical substances can mix with tap water after severe rainfall and flood disasters, stated that the mixing of sewage, agricultural waste, and chemical substances into drinking water sources can create serious public health risks. Stating that contaminated water can lead to cholera, typhoid, hepatitis A, and various intestinal infections, Sur said, “Water that is clear, odorless, and normal in taste can also contain disease-causing microorganisms.” Emphasizing that boiling water is not sufficient in all cases, Prof. Sur specifically warned citizens against chemical contamination.

Dean of Üsküdar University Faculty of Medicine and Ministry of Health Consultant Prof. Haydar Sur evaluated the points citizens should pay attention to regarding tap water safety after floods and heavy rainfall.

How do floodwaters mix with the drinking water network?

Prof. Haydar Sur stated that severe rainfall can cause both microbiological and chemical contamination in drinking water sources, adding that waste carried by floodwaters poses a significant threat.

Prof. Sur said, “Floodwaters can contain sewage, animal waste, agricultural waste, garbage, and various chemical substances. The access of these waters to drinking water sources, damage to treatment systems, or infiltration into the distribution network can impair water quality.”

Emphasizing that physical damage to the water network also increases the risk of contamination, Prof. Sur said, “Bacteria, viruses, and parasites can mix with water through human and animal feces. Cracks in pipes or a drop in water pressure can lead to surrounding contaminated water entering the network. Increased turbidity of water can reduce the effectiveness of disinfection. Furthermore, fuels, pesticides, industrial waste, and other chemicals can also mix with water sources.”

Contaminated water can lead to cholera, typhoid, and hepatitis A!

Prof. Sur pointed out that consuming contaminated water can cause serious infectious diseases, specifically noting that the mixing of fecal-origin microorganisms into water poses a significant risk.

Prof. Sur stated, “As a result of consuming contaminated water or eating food prepared with it, bacterial infections such as cholera, typhoid, shigellosis, and some E. coli infections; viral infections such as hepatitis A, norovirus, and rotavirus infections; and parasitic infections such as giardiasis and cryptosporidiosis can be observed.”

Noting that these diseases can manifest with different symptoms, Prof. Sur said, “These diseases can cause diarrhea, vomiting, abdominal pain, fever, and fluid loss. In some infections like hepatitis A, symptoms such as jaundice, weakness, and nausea may become prominent.”

“Water that is clear, odorless, and normal in taste can also contain disease-causing microorganisms”

Prof. Haydar Sur stated that one of the most common misconceptions citizens fall into when assessing water safety is relying on its appearance, saying, “Water that is clear, odorless, and normal in taste can also contain disease-causing microorganisms. Changes in color, odor, and taste may indicate contamination; however, their absence is not proof of microbiological safety.”

Stating that most contaminants cannot be noticed by the eye, Prof. Sur commented, “Some bacteria, viruses, and parasites are too small to be seen. Similarly, some chemical pollutants can also be present without changing the sensory properties of the water.”

“Boiling water is not sufficient against all kinds of contamination”

Prof. Sur noted that when tap water safety is suspected after a flood, citizens may resort to boiling the water, emphasizing that this is only effective under specific conditions.

“If microbiological contamination is present, proper boiling inactivates most disease-causing microorganisms. However, it is not sufficient against all types of water contamination,” said Prof. Sur, adding that chemical contamination should be evaluated differently.

Prof. Sur made the following warnings:

“Fuels, pesticides, heavy metals, or industrially sourced chemicals do not become safe by boiling. Some substances can even become more concentrated as water evaporates. Some toxins are not eliminated by ordinary boiling. Sewage-related contamination can be not only chemical but also microbiological. While boiling can inactivate microorganisms, it does not guarantee the chemical safety of the water.”

Emphasizing that water potentially contaminated with fuel, chemical waste, or other toxic substances should not be boiled and consumed, Prof. Sur highlighted the importance of using safe alternative water sources in such situations.

“Boil water for use” and “Do not drink water” warnings do not mean the same thing!

Prof. Sur stated that when tap water is suspected of being contaminated, announcements from the municipality, water and sewage administration, and health authorities should be followed first, adding that the nature of the warnings given to citizens is of great importance.

Prof. Sur said, “‘Boil water for use’, ‘do not drink water’, and ‘do not use water for any purpose’ warnings do not mean the same thing. While boiling may be sufficient for microbiological risks, it is not a solution in cases of chemical contamination or when contact with water is also dangerous.”

Noting that the stated restrictions must be strictly adhered to if authorities declare the water unsafe, Prof. Sur recommended using verified safe bottled water or safe water provided by authorized institutions.

Prof. Sur said, “Suspect water should not be consumed; it should not be used to prepare tea, coffee, soup, and baby formula. Safe water should be preferred for brushing teeth, washing food, and making ice. Since refrigerator water and ice dispensers are also connected to the mains, they should not be used during the warning period. Pacifiers, baby bottles, and similar items that have come into contact with suspect water and are put into the mouth must be cleaned using safe methods.”

Vegetables and fruits washed with contaminated water can also be a source of infection!

Prof. Haydar Sur stated that contaminated tap water can pose a health risk not only when consumed directly but also when used in food preparation, saying, “Contaminated water can cause infections not only when consumed directly but also during food preparation, cleaning kitchen utensils, and making ice. Foods consumed without cooking, in particular, require more attention.”

Emphasizing that vegetables and fruits should not be washed with tap water if it is not safe, Prof. Sur continued:
“Salads, fresh greens, raw vegetables, and fruits can carry disease agents if they come into contact with contaminated water. Being washed does not always make a product that has been in contact with contaminated water safe. Safe water should be used for soups, sauces, beverages, baby formula, and foods to which water is added before cooking. While cooking can inactivate some microorganisms, it does not eliminate chemical contamination.”

Prof. Sur, pointing out that ice and kitchen utensils can also carry risks, warned, “Ice prepared with unsafe water should not be used. Freezing ice does not make water safe.”

Noting that safe water and appropriate disinfection methods should be used for cleaning dishes, Prof. Sur emphasized the importance of cleaning baby bottles and pacifiers used for infant feeding with safe water and disinfecting them properly.

Disease symptoms can appear days, even weeks later!

Prof. Haydar Sur pointed out that symptoms of contaminated water-borne infections may not appear immediately, stating that citizens should observe their health status, especially in the period following floods and water surges.

Prof. Sur said, “The time it takes for symptoms to appear varies depending on the type of microorganism ingested, the amount of exposure, and the individual's immune status. Some diseases can show symptoms within hours, while others may do so days or weeks later.”

Sur stated that infections can begin with diarrhea, vomiting, fever, and abdominal pain, adding that some symptoms require urgent medical evaluation.
Prof. Sur said, “Medical evaluation should not be delayed in cases of blood in the stool, severe or increasing abdominal pain, high or persistent fever, and inability to take fluids due to frequent vomiting. Symptoms of dehydration such as a significant decrease in urine output, dry mouth, dizziness, or fainting should also be taken seriously.”

Emphasizing that particular attention should be paid to confusion, excessive sleepiness, and a significant deterioration in general condition, Prof. Sur said, “Bloody diarrhea, significant change in consciousness, fainting, or signs of severe fluid loss require urgent evaluation.”

Scientific analyses must be performed before tap water is reused!

Prof. Haydar Sur stated that the safety of the water network after floods and heavy rainfall cannot be assessed solely based on observation, noting that comprehensive checks must be conducted before water can be reused.

Prof. Sur said, “The re-declaration of tap water as safe is not solely dependent on the water starting to flow or appearing clear. The entire system, from the water source to the treatment plant, from the distribution network to the consumer's tap, must be evaluated.”

Reminding that the World Health Organization recommends ensuring water safety through risk-based management and independent supervision, Prof. Sur noted that the water source and infrastructure must be examined, microbiological, physical, and chemical analyses must be performed, treatment and disinfection processes verified, and samples taken from different points of the network.

Emphasizing the importance of timely and accurate public information during this process, Prof. Sur said, “Water safety is determined by the controls of authorized institutions. After a flood, water cannot be declared reusable merely by its appearance or taste.”