Do You Need A Patio Cleaner? Is it Necessary?

Last Updated on August 16, 2023 by Real Men Sow

Chemicals in cleaning products are common as they were the only way to clean effectively and maintain hygiene. While eco-friendly products are becoming more popular for indoor use, it seems contradictory that we would be using dangerous ingredients to make our homes safer. However, outdoor jobs still require us to use them.

Toxic chemicals are now commonplace to clean outdoor surfaces. Many of the chemicals we use can be dangerous if they are ingested, touched, or breathed in. Because they are outdoors, and not in a room, we expect any adverse effects to be minimized or diluted by the environment.

Dangers of Outdoor Cleaning Products

Many chemicals in outdoor cleaning products can be dangerous for us, our pets, wildlife and plants. They can also end up in our waterways and cause severe environmental damage. Many patio cleaner/cleaners can kill living organisms. These chemicals can be called biocides, or more precisely, algaecides, pesticides, fungicides or herbicides. They may also contain detergents for cleaning, as well as acids that can be either organic (acetic) or inorganic (hydrochloric). These all serve the same purpose of biocidal function.

The same applies to molds, algae, moss and lichen. Once they have been killed, they don’t magically disappear. They remain, even though dead, until they can be dislodged or blown away. Patio cleaner is often sold as a work-free solution that promises sparkling results and surfaces that look ‘just like new.’ These claims almost always seem exaggerated. Although statements like “no scrub” and “no pressure washing” are appealing to our indolent tendencies to be more nimble, the actual removal of the contaminants will require gravity, weather, or your help.

The Type of Organism

It is important to consider the type of organism that you are trying to get rid of. For example, algae, fungi, and most mosses need damp conditions to thrive. However, lichens can live in much more dry environments. This also impacts the product’s ability to work quickly. Some products can be applied quickly, but they are often highly aggressive and need protection for the user and their surroundings. Brick acid is one example. If you enjoy the weather, then the organisms living on your patio will be too. You will see faster results if you have warmer, more sunny weather. However, slower results will be achieved if it is colder and wetter.

You can use a biocide to clean surfaces of living organisms. It is quick, easy and effective. Most commercially available cleaners work. Where they don’t, it could be due to the applicator (for example, wrong dilution, timing, or if it’s too hot or cold). The best way to clean a surface is to combine some physical action with a cleaner (biocide), and take your time.

Pay Attention To The Warnings On Labels

Any of these could indicate the presence of potentially dangerous or aggressive ingredients.

  • Harmful to the Environment
  • If swallowed, it can be dangerous
  • Do NOT induce vomiting
  • Contact with skin can be harmful
  • Causes serious eye damage
  • Causes skin irritation
  • Long-lasting toxic effects on aquatic life.
  • Call a poison center if swallowed
  • Dry, non-toxic and safe to use around pets and children
  • Protective clothing is recommended
  • Don’t flush it down the toilet

Avoid products that contain these ingredients if you don’t want to be exposed to any potentially harmful side effects. However, patio cleaner is most often made up of QUATs, including BACs and sodium salts.

Sodium Hypochlorite

Sodium hypochlorite can be found in a pale yellowish-yellow solution, also known as liquid bleach. The solution’s unstable nature means that it is easy to decompose, releasing chlorine, the active principle in such products. Sodium hypochlorite, the most important and oldest chlorine-based bleach, is still very useful. Pure sodium hypochlorite is a water-soluble yellowish liquid with about 12% chlorine.

What It Does and What it Is

  • Extremely potent oxidizing agent. It can corrode or destroy most metals and react with acids, peroxides, as well as many other chemicals to make toxic chlorine gas.
  • Bleach can dissolve paper, cloth, as well as many organic materials.
  • Powerful disinfectant and oxidizer, even at a household strength of 5%.

Warning: When working with bleach, be careful. Even in the most diluted form, bleach fumes can cause severe irritation to the respiratory tract. Mild irritation can occur from skin contact. Long-term eye contact can lead to permanent damage. Bleach is free of any cleaning agents.

Quaternary ammonium compounds, (QUATS)

The persistent disinfectant quaternary ammonium compounds are primarily used for antibacterial activity. However, they can also cause gastrointestinal symptoms such as nausea and vomiting, coma, hypotension, and death. Products containing QUATs may also be labeled as non-caustic, acid-free, biodegradable or non-caustic.

Benzalkonium chloride (BAC’s)

Also known as BZK, BKC, BAC, alkyldimethylbenzylammonium chloride and ADBAC, is a type of cationic surfactant. It is an organic salt that can be classified as a quaternary amino compound. BACs are an important ingredient in patio cleaners that act as an algicide for clearing algae, moss and lichens from paths. BACs can be used to kill bacteria, viruses, fungi and protozoa. Bacterial Spores are considered resistant. While pH does not affect activity, it can be affected significantly by higher temperatures and longer exposure times.

Dilute solutions are used in BAC formulations intended for consumer use. Concentrated solutions can be toxic to humans and cause irritation and corrosion to the skin and mucosa. They can also cause death if consumed in sufficient quantities. The maximum amount of benzalkonium chloride that causes no irritation to intact skin or acts as a sensitizer is 0.1%.

What It Does and What it Is

  • BAC can be very toxic for aquatic life and to dogs and cats.
  • Products containing BACS are non-toxic if they are dry. However, if the chemical is soluble, it remains active.
  • BAC’s can be irritating and cause severe reactions in cats who have licked on or walked on treated surfaces. They may also have adverse effects if they are ingested by their paws. Similar reactions can also occur in dogs.

Remember: Products containing BACs may also be labeled as non-caustic, acid-free, bleach-free, and biodegradable. However, their resistance to microbial degradation can lead to accumulation in aquatic environments where toxic effects can occur..


Benzalkonium chloride can cause severe eye irritation and skin irritation in humans. It is suspected to be a respiratory toxicant, neurotoxicant, immune-toxicant or gastrointestinal toxicant. BAC can be absorbed through skin contact and ingestion. On heating, BAC’s are broken down and produce toxic and corrosive gasses such as ammonia and chlorine.

Tetrasodium Ethylene Diamine Tetraacetate (EDTA)

EDTA is the salt resulting from the neutralization of ethylenediaminetetraacetic acid It is an amino polycarboxylic acid a colorless, water-soluble solid. It is used extensively to dissolve limescale. It is useful because it can sequester metal ions like Fe3+ and Ca2+. Also, it can be used to stop mold growth and other microorganisms.


EDTA can cause nausea, vomiting, diarrhea and abdominal cramps. It can also cause low blood pressure, skin issues, fever, and skin problems. Too much can lead to kidney damage, dangerously low levels of calcium, and even death.

Concerns about EDTA’s biodegradability have raised concerns. It is so widely used that it has been deemed a persistent organic pollutant. While EDTA has many benefits in various industrial, pharmaceutical, and other applications, its long-term persistence can pose serious environmental problems. The rate of EDTA degradation is slow. It is primarily caused by sunlight.

Hydrochloric acid (includes muriatic Acid HCI)

Be careful not to let the acid touch clothing, skin, or eyes. The fumes can also be toxic and could cause damage to the nose, throat, and lungs. It can damage or kill any organic matter, including plants, animals, children, and pets.

Acidic mists are formed by concentrated hydrochloric acids (fuming Hydrochloric Acid). The solution and the mist have a corrosive impact on human tissue. They can cause irreversible damage to the eyes, respiratory organs, skin and intestines.

Acid cleaners can cause damage to metal, limestone, concrete, lime-containing (cement), masonry composites, jointing plaster, and other porous materials. Use extreme caution.

Diethylenetriamine (abbreviated DETA and also known as 2,2′-Iminodi(ethylamine)

As a wood perseverative, it can be added to decking cleaners. Inhalation of dipropylene triamine can be very dangerous and it can also cause skin irritations. It can be harmful if swallowed. Sensitization may result from skin contact.

Sodium Metasilicate (includes inorganic sodium sals)

Although sodium salts aren’t inherently dangerous, they can cause damage to plants and be toxic to many soil organisms.

Real Men Sow
Real Men Sow

Hello, I’m Pete and I’m currently based in the west of Scotland, in a small place called Rosneath, where I’m exploring my garden adventures. I personally started gardening around 6 years ago and initially, I started out by growing my favorite fruits and berries, such as strawberries, Raspberries & Gooseberries. Since then I’ve added a lot of vegetables and working closely with my neighbor, it’s been a lot of fun.