Disinfection and Deep Cleaning Done Properly

Cleaning removes soil. Disinfecting kills microorganisms. Doing the second on top of the first does not work, because disinfectant cannot get through a film of grease or limescale to reach the surface underneath. So the order is fixed: clean, rinse, dry, then disinfect. Everything else is theatre.

It is also worth saying what disinfection is not. It is not sterilisation, and a home does not need to be sterile. A normal house with normal traffic needs targeted disinfection in a handful of places, done properly, rather than a fine mist of something over every surface once a week.

Cleaning and disinfecting are not the same job

Cleaning is mechanical: you lift soil off a surface with detergent, water and friction. Disinfecting is chemical: you apply a product at the right concentration for the right contact time and it reduces the number of viable organisms. Sanitising sits between the two, and means reducing bacteria to a level considered safe by a public health standard rather than eliminating everything.

The distinction matters because the products are different and the failure modes are different. A cleaner that leaves a streak has failed visibly. A disinfectant that was wiped off after ten seconds has failed invisibly: you think the job is done, and nothing has happened.

What is contact time, and why does everyone get it wrong?

Contact time (also called dwell time) is how long a wet surface must stay wet for the product to work. It is printed on the label, and it is usually longer than people expect: often one minute for a bathroom spray, five minutes for a food-contact sanitiser, ten for a heavy-duty product.

The common mistakes:

• Spray and wipe. The most widespread error. You have cleaned the surface and done nothing to the organisms on it.
• Spray and let it dry. Sometimes fine, sometimes not. Check the label: some products work as they dry, others need to be wet for the full time and then rinsed.
• Over-diluting. Half the dose does not do half the job. It does none of the job, and it costs you the product.
• Mixing products. Bleach and anything acidic releases chlorine gas. Bleach and ammonia releases chloramine. Neither is a small mistake in a closed bathroom.
• Reusing a cloth that has already wiped a dirty surface. You are smearing, not disinfecting. Fold the cloth and use a fresh face.

Where does disinfection actually matter?

A short list, and it is shorter than the cleaning aisle suggests:

• Kitchen: the worktop where raw meat sits, the chopping board, the sink and the tap handles, the fridge door handle, the bin lid.
• Bathroom: the toilet flush and seat, the tap handles, the shower floor, the bath mat area.
• High-touch points: door handles, light switches, stair rails, remote controls, the kettle handle, the front door keypad.
• After illness: anything the unwell person touched, their bedding, their crockery, the bathroom they used.
• After a rental changeover: the same high-touch list, plus the kitchen and bathroom as above.

What does not need disinfecting daily: floors, walls, soft furnishings, bookshelves, decorative objects. Cleaning those properly is enough. Constant disinfection of everything is expensive, it exposes the household to more chemistry than it needs, and it does nothing useful.

Which products are worth using?

Three families cover it, and each has a place:

• Alcohol, 60 to 80 percent (ethanol or isopropanol). Fast, evaporates clean, safe on most hard surfaces and electronics. Good for small high-touch items and anything where you cannot rinse. Flammable: keep away from the hob and never spray into a flame.
• Chlorine bleach, diluted. Cheap and effective against a wide range, including mould spores on hard surfaces. Corrosive to metals, damaging to grout over time, harsh on the lungs, and it kills the bacteria in a septic tank. Use it for the toilet bowl and for a mould outbreak, and not much else. Never mix it with an acid or an ammonia-based product.
• Accelerated hydrogen peroxide or quaternary ammonium compounds, as labelled. Good general-purpose hard-surface disinfectants, and usually the better choice for a home on a tank because they break down more benignly. Read the contact time; it varies a lot between products.

For a septic tank or grey water system, keep bleach for the toilet bowl only, and use oxygen-based products elsewhere. This is not a small distinction in this area: a good number of properties from Calahonda eastwards are not on mains drainage.

The room by room deep clean, in the right order

Work top to bottom, dry to wet, and furthest from the door to nearest, so you are not walking through what you have just cleaned.

Kitchen. Empty one cupboard at a time and wipe the inside. Degrease the extractor filter in hot water and washing soda. Clean the oven with the product on for its full dwell time, then scrub with a non-scratch pad. Pull the fridge out and clean behind it and the drip tray. Descale the kettle and the tap aerator with citric acid. Clean the splashback and the seals around the sink.

Bathroom. Descale first, with citric acid or a proprietary descaler, because limescale sits on top of everything else and protects it. Then clean with detergent, rinse, and dry. Then disinfect the high-touch and wet areas. Clean the extractor fan grille, the shower trap, and behind the toilet. If the silicone has black mould in it and cleaning does not shift it, it needs replacing, not bleaching.

Bedrooms and living areas. Dust from the top down: picture rails, the tops of wardrobes and doors, lampshades, then surfaces. Vacuum the mattress and turn it. Wash or dry clean curtains and cushion covers. Clean the windows inside and the frames and tracks, which is where the calima dust collects. Skirting boards last, because everything above them has just dropped onto them.

Whole house. Light switches, door handles, plugs and sockets, the tops of doors, the insides of wardrobes, the top of the fridge, under the beds. These are the places that make the difference between a house that looks clean and one that is.

Why is drying the most important step?

Because moisture is what lets organisms come back. A bathroom that is cleaned and disinfected but left wet grows mould again within a fortnight. A kitchen worktop left damp grows bacteria overnight. A washing machine with the door shut and a wet drum grows a biofilm.

So the last action in every room is drying: a dry microfibre over the surfaces, the squeegee on the shower screen, the window open or the fan running, the washing machine door ajar. It takes two minutes and it is what keeps a deep clean looking like a deep clean three weeks later.

What does the climate here change?

Two things. Hard water means limescale builds on every wet surface faster than in the UK, and limescale is porous, so it holds soil and organisms. A surface that looks clean but feels slightly rough is scaled, and it has not really been cleaned. Descaling is not a cosmetic job here, it is part of the hygiene job.

Heat and closed windows are the second. In August a house can sit at thirty degrees with the air conditioning on recirculation and every window shut. Moisture from showers and cooking has nowhere to go, and a bathroom that would dry out in a British spring stays damp. Ventilation, extraction and drying matter more here, not less.

Calima is the third, and it is easy to miss. When the dust comes in, it settles on windowsills, into window tracks, onto balcony tiles and into the tops of wardrobes. It is fine, slightly gritty and it holds moisture against a surface. After a calima week, a deep clean means the horizontal surfaces and the window tracks, not just the floors.

How often should you do it?

A reasonable rhythm for a normal home:

• Daily: kitchen surfaces, sink, high-touch points in the bathroom, floors in the main rooms.
• Weekly: bathrooms properly, floors everywhere, bedding and towels, bins.
• Monthly: washing machine hot cycle, extractor filter, fridge, shower head descale.
• Seasonally: the deep clean, one room at a time. Oven, cupboards, windows and frames, mattresses, curtains, the insides of wardrobes.

Holiday rentals are different: a proper clean and disinfection between each set of guests, on the high-touch list at minimum. That is not a deep clean every Saturday, it is a consistent changeover standard, and it is what guests actually notice.

A deep clean is the job people put off for a year and then wish they had booked sooner. If that is where you are, tell us the size of the property and roughly when it was last done properly, and we will give you a straight answer on how long it takes. +34 604 42 21 31, [email protected], seven days a week.

If you would rather hand it over: professional deep cleaning and disinfection in Marbella.