The difference between cleaning and disinfecting: when soap and water is enough at home

Cleaning removes dirt, grease and, with them, most germs from a surface, using water, washing-up liquid and mechanical wiping. Disinfecting uses chemicals to kill the microorganisms that remain on the surface. In an ordinary household, cleaning is usually enough. Add disinfection mainly when someone at home is ill or has a weakened immune system, and always only on a surface that has been washed beforehand.

Three terms: cleaning, sanitising, disinfecting

In Czech these words are often used interchangeably, but the US authorities CDC and EPA distinguish between them precisely. The distinction is useful at home too, because each step has a different purpose and a different procedure.

According to the CDC, cleaning removes most germs, dirt and impurities from surfaces, sanitising lowers germs to a safe level and disinfecting kills most germs. The EPA adds that sanitising targets bacteria and is not intended to kill viruses, whereas disinfecting kills both viruses and bacteria.

Why wash first and only then disinfect

A disinfectant must come into direct contact with germs. A layer of grease, food residue or dust protects them, and part of the product is used up on it. That is why the CDC explicitly advises washing the surface with soap and water first, and only then sanitising or disinfecting as needed.

In practice this means two steps, not one. The exception is products that the manufacturer labels as both cleaning and disinfecting; even for those, however, the label usually describes how to proceed with a heavily soiled surface.

When ordinary cleaning is enough at home

For most surfaces in a home, soap or washing-up liquid and water is sufficient. The CDC states that sanitising or disinfecting at home is probably not needed if no one in the home is ill. Regular cleaning is appropriate for:

• floors, tables, shelves and windowsills,
• the kitchen worktop and hob after cooking,
• the washbasin, bath, shower and mirrors,
• frequently touched surfaces: handles, switches, remote controls, handrails. The CDC recommends cleaning these regularly.

When cleaning, much of the work is done by the wiping itself, so the condition of the cloth matters too. Use one cloth for the toilet, another for the bathroom and another for the kitchen, wash them after cleaning and let them dry completely. A damp cloth left by the sink tends to spread dirt rather than remove it.

How often to clean individual areas is summarised in the article How often to clean a flat.

When disinfecting makes sense

• Illness in the household. If someone has a gastrointestinal or respiratory infection, disinfect frequently touched surfaces, the toilet, taps and remote controls. The CDC recommends disinfecting when someone is ill or at higher risk of illness.
• A person with a weakened immune system in the household, for example after treatment or a transplant. Consult the treating doctor about the right procedure in such a situation.
• After a flood or water damage, when the CDC recommends sanitising surfaces that come into contact with food.

Raw meat and the kitchen

With raw meat, thorough cleaning is usually enough if you do it straight away. The CDC advises washing utensils, chopping boards and worktops with hot water and washing-up liquid after preparing each food, having a separate chopping board for raw meat, and not washing raw chicken before cooking, as this spreads germs around the sink and worktop. Wash your hands with soap and water for at least 20 seconds.

How to disinfect safely and effectively

1. Read the label. Find out which surfaces the product is intended for, how to dilute it and whether the surface must be rinsed afterwards, especially for food-contact surfaces and children's items.
2. Wash the surface first with washing-up liquid and water, and let it dry or wipe it dry.
3. Protect yourself. The CDC advises using the protective equipment recommended by the manufacturer, such as gloves or goggles, and ensuring good ventilation.
4. Observe the contact time. The EPA points out that you need to pay attention to the contact time, that is, how long the surface must stay wet. If the product dries sooner, apply it again.
5. Do not mix products. The CDC states this as a general rule and, for chlorine bleach, explicitly warns that mixing it with ammonia or other cleaning products creates a toxic gas.
6. Wash your hands after the work and store the products out of the reach of children and pets.

According to the CDC, label diluted solutions so that nobody mistakes the bottle. Dilute with room-temperature water unless the label states otherwise.

Children's items, bottles and toys

For items that children put in their mouths, heat sanitising is preferable to chemicals. The CDC states that baby equipment and some toys can be sanitised by boiling, steaming or with a weak chlorine solution, and for some items a dishwasher's sanitising cycle will do. Always follow the manufacturer's instructions for the item, however, because not every plastic withstands high temperatures.

After sanitising, leave the items to dry on a clean, unused tea towel. The CDC does not recommend drying them with a kitchen towel, as germs could be transferred to them again.

What to use where: overview

The risks of excessive disinfection

More disinfectant does not mean a cleaner home. Unnecessary use has several drawbacks:

• Airways. The CDC warns that some cleaning and disinfecting products can trigger asthma.
• Risk of poisoning and mix-ups. The more bottles in the home, the greater the chance that a child gets to them or that two products are mixed by mistake. Which combinations are dangerous is described in the article Which cleaning products must never be mixed.
• Damage to surfaces. Some products can damage stone, wood or delicate plastics. Always test them in a hidden spot and follow the surface manufacturer's recommendations.
• A false sense of cleanliness. Disinfectant sprayed on an unwashed surface does not remove the dirt and may not work fully.

Disinfectants do not belong on skin, in food or on animals. The CDC explicitly states that they should not be used to wipe or bathe animals.

Practical summary for the home

• Usually: water, washing-up liquid, a microfibre cloth, regularity.
• After raw meat: hot water and washing-up liquid straight away, separate chopping boards.
• When someone in the family is ill: wash first, then disinfect frequently touched surfaces according to the label.
• Always: ventilate, wear gloves, do not mix products, store them out of the reach of children.

Regular home cleaning usually means thorough cleaning; if you would like certain surfaces disinfected, it is best to state this explicitly in the order. How home cleaning works and what it includes can be found in the service description.