Protect Your Lawn: Understanding the Effects of Car Wash Soap on Grass

Taking your car to a professional car wash can be hectic in your busy schedule. Many car owners prefer to give their car a complete wash on their driveways or lawns. The residue water often goes to the lawn. You might think, does car wash soap kill grass?

No, car wash soaps don’t kill the grass. Car wash soaps generally don’t have harsh chemicals to kill grass or plants in your lawn. But cleaners with highly acidic compounds, chlorine, etc., can damage your lawn and harm the environment.

Let’s get to know more about the effect of car wash soaps and tips to wash your car without destroying your lawn.

Does Car Wash Soap Really Kill Grass?

There is a common misconception among car owners that washing your car on the lawn might kill grass and be harmful to the environment. Let us bust the myth. Car wash soaps or car shampoos aren’t made with abrasive or corrosive compounds like other harsh cleaning agents.

Instead, they are made of mild cleaning agents that aren’t harmful to grass or other plants. The wastewater after a car wash doesn’t contain any harmful compound from the car washing soap.

But dirt, oil, and grease might get mixed into the water, which can be harmful to the environment if the waste water goes into the drainage.

What Car Wash Soap Is Safe for Grass and Lawn?

While washing your car on the lawn is a great way to conserve water and hydrate the lawn at the same time, wrong soap can do more harm than good. Some car owners tend to wash their cars with regular dish soaps, detergents, or other cleaning agents.

These chemicals often contain harmful compounds to the environment, such as chlorine or phosphate. Some of these compounds aren’t biodegradable, so the wastewater will carry them away to the drainage system.

To prevent your lawn from getting destroyed, you need to use car wash soaps or shampoos. These cleaners are made with no chlorine or phosphate. They are often biodegradable, so you can safely wash your car without killing grass or the lawn.

While buying a car wash soap, check whether it contains chlorine or phosphate. Also, check whether the soap is biodegradable or not. Using such a soap won’t be heavy on the grass or the lawn and will keep the environment safe.

Is Biodegradable Car Wash Soap Safe on Lawns and Plants

To avoid lawn damage, you must use biodegradable car wash soap to clean your car. Regular cleaners contain cleaning agents like chlorine and phosphate that create the perfect environment for algae to grow.

Most grasses and plants on your lawn might not tolerate these harsh chemicals. Plants can die if you use an excessive amount of abrasive cleaners on your lawn. To keep your lawns and plants safe biodegradable car wash soap is the best option out there.

When you wash your car with biodegradable soap, it disintegrates over time. Fungi and bacteria can consume these compounds, so everything will be absorbed by the soil.

As a result, biodegradable car wash soap is completely safe on lawns and plants. Though using gray water might be a great way of conserving water, the residue coming from detergents or dish soaps will kill the lawn.

So, we suggest you only use clean water and biodegradable car wash soap to clean your car.

Can You Wash a Car with Dish Soap?

Theoretically, it is okay to use dish soap to clean any dirty surface. But you shouldn’t use dish soap to wash your car. You shouldn’t even use laundry soaps or detergents to wash your car, either. Ask why?

Dish soaps and detergents are considered abrasive cleaning agents. If you see how dish soaps clean dirty and greasy utensils, you’ll get the answer. When you use dish soap on your car, its compounds react with the car paint.

As a result, the top coating of the car gets damaged. This causes an oxidation reaction which reduces the shine of the car paint. Your car will start looking dull if you use dish soap on the car.

If you continue to wash your car with dish soap, the topcoat will break down. The paint layer will also start to break, and you will notice scratches or patches on your car. This is because dish soaps aren’t made to be used on your car paint.

Dedicated car wash soaps are far more suitable for the paint. They won’t damage the wax coating of your car’s paint. As a result, the paint will remain shiny for longer without any ugly scratches on the car.

Effect of Dish Soap on Lawns

As we have already mentioned, dish soaps are downright harmful to the grass and plants on your lawn, even to the environment. Though these are called soaps, you can actually call them detergents as the cleaning solution of dish soaps act like detergents.

They break down the organic compounds in your dishes. In the same way, they will break down the natural oils on the grass and other plants. As a result, plants will be more prone to infection and eventually die.

Dish soap solutions are sometimes used to kill insects. By using soapy water on lawn, you can prevent the growth of algae and harmful insects. But that will also damage grasses and other plants a lot.

So, we suggest you don’t use dish soap on lawns.

Tips for Washing Your Car on the Grass

Washing your car at home might be fun. Sprinkling water on your car or seeing all dirt wash away is too satisfying. But if you don’t know the right tips for washing your car, you might damage the car as well as the lawn.

Let’s check some pro tips to wash your car right without being too harsh on both the car and the lawn.

Always Use a Dedicated Car-Wash Soap

Using a soap that won’t kill grass to wash your car is of utmost importance. Don’t ever use dish soap to clean your car. It will damage the paint of your car as well as the grass and plants on the lawn.

The wastewater containing dish soap residue might go into the waterways and affect the environment badly.

Use A Water Saving Hose Nozzle

If you want to wash your car on your lawn without killing the grass, use a water saving hose nozzle. These nozzles reduce the amount of water coming out of the hose so you don’t saturate the ground or get too much soap on it at one time.

Don’t Pour the Rinse Water on the Lawn

Letting your lawn drink some water while washing your car might be good sometimes. But flooding the lawn with all the rinse water from washing the car can be risky.

The lawn can get muddy if you throw all the rinse water on the lawn. It will be better to have a dedicated space for washing the car. You can make a channel to the drainage system so that the wastewater can directly go into the drainage.

Be Cautious About the Tire Marks

Driving your car on the lawn might compact the soil as well as leave tire marks. The marks will be much deeper if your car is heavy. Keeping your car close to the driveway or concrete surface is the key.

If the marks are too deep, you can use a hand roller to level the surface out.


In most forums regarding car wash on the lawn, you’ll find a very common question. The question is, does car wash soap kill grass? We want to assure you that car wash soap won’t kill grass because they are made of compounds safe for the environment.

If you avoid using dish soaps to wash your car, it will save your car’s paint and the grass on the lawn from damage. Biodegradable car wash soaps are the best solution out there. They will be mild on your car, the lawn, and even the environment. Make washing your car more fun while keeping an eye on the safety of your surroundings.

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