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How Does a Car Wash Reverse Osmosis System Work?

Environmental sustainability and resource conservation are vital to the future. In fact, 69% of global consumers say they care more about sustainability than they did just two years ago. That’s why all types of businesses are searching for ways to reduce the amount of resources they use and make their operations more environmentally friendly.

Take car washes as an example. An average car wash business uses between 15 to 80 gallons of water per wash. Multiply that by how many cars you wash daily, and you’ll get a lot of gallons of wastewater daily. That’s why pioneers in the car wash industry are embracing water recycling methods like reverse osmosis to conserve resources and minimize environmental harm. 

Read on to learn what a car wash reverse osmosis system is and how you can benefit from using one in your car wash business.

What Is a Car Wash Reverse Osmosis System?

A car wash reverse osmosis system is an advanced water filter for car washing. It transforms used car wash water into a reusable resource. 

Reverse osmosis — also called RO — utilizes a semipermeable membrane to remove impurities, contaminants, and dissolved solids from water. Various industries use it for a multitude of purposes. Some examples include:

  • Wastewater treatment
  • Desalination
  • Ordinary tap water purification
  • Agriculture and irrigation
  • Beverage production
  • Aquaculture
  • Food processing
  • Cosmetics and toiletries production
  • Hospital and laboratory water purification

In the car wash industry, reverse osmosis produces high-quality, purified water for the final rinse stage of the car cleaning process. This purified water provides a spot-free rinse and reduces the need for manual drying.

How Does a Car Wash Reverse Osmosis System Work?

Essentially, reverse osmosis filters very small contaminants out of water. The water first goes through pre-filtration and then through the other stages of reverse osmosis. It goes like this:

  • Pre-filtration
  • Pressurization
  • Filtration
  • Separation
  • Disposal
  • Optional polishing through additional processes
  • Reuse of recycled water

Here’s a further exploration of these steps.


Reverse osmosis uses a semipermeable membrane, essentially a selective filter, that lets clean water through while trapping contaminants. But, because this membrane is susceptible to damage from larger particles, the water must go through pre-filtration first. Essentially, pre-filtration acts as a first line of defense. 

During pre-filtration, mains water — or water from the source — is strained through a filter that focuses on larger particles like sand, dirt, and silt. In addition to protecting the semipermeable member the water will reach later, this stage aids in:

  • Optimizing flow rate by delivering partially filtered water that won’t clog the membrane
  • Boosting cost efficiency by avoiding damage that speeds up the need to replace the membrane

The pre-filtration stage employs multiple types of filters simultaneously to filter its target particles effectively. They include the following:

  • Sediment filters capture and eliminate larger particles like sand and silt.
  • Carbon filters eliminate chlorine, chloramine, and other organic compounds.
  • Depth filters catch other particles of varying sizes.

Pressurized Water Flow

The pre-filtered water then goes through a pressurized water flow. Since the membrane filter is semipermeable, it requires pressure to get the water through.

Upon the initial pre-filtration stage, the water enters a pressurized chamber, where it gets propelled against the membrane. The high pressure pushes the water through the membrane’s microscopic pores while it captures minerals, contaminants, and other impurities.

Separation of Contaminants

The impurities and mineral salts stay behind the membrane as the pressurized water flow moves through it. This triggers a division of purified water that passes through while contaminants stay behind. The result is a separation of pure water and reject water.

Pure Water and Reject Water

Once the purified water emerges after passing through pre-filtration and pressurized water flow stages, the system collects and stores it for final filtration and polishing.

Reject water, which has a concentrated stream of residual impurities, dissolved solids, minerals, and contaminants that could not traverse the semipermeable membrane, goes toward disposal. 

Reject Water Disposal

You can dispose of reject water from a car wash reverse osmosis system in several ways, depending on regulations and how you prefer to deal with it. You can use:

  • A drainage system that safely directs the reject water into your facility’s existing drainage or sewer system
  • Further filtration to recycle the reject water back into your water treatment system and put it through a carbon filter or other car wash filter systems
  • Off-site disposal for heavily contaminated water that doesn’t meet local regulatory standards for discharge
  • Land application, where reject water may be suitable for irrigation purposes, depending on the contaminants present

Your preferred method of reject water disposal depends on factors such as local regulations, the level of contaminants in your reject water, and available infrastructure. For example, using your drainage system for reject water is subject to compliance with local regulations to ensure that the reject water doesn’t contain pollutants or substances that could harm the environment or strain wastewater treatment facilities.

Final Filtration and Polishing

Some car wash facilities implement further filtration beyond reverse osmosis for various reasons. While reverse osmosis systems remove many particles and suspended solids, some minute particles may still pass through. Additional filtration options that high-quality facilities use are:

  • A car wash water deionizer: A car wash deionized water system is a specialized water treatment system designed to produce extremely pure water by removing virtually all mineral ions and impurities through an ion exchange process.
  • A car wash water softener: If you’ve got a hard water car wash, a water softener for washing cars can preserve vehicle surfaces, aid in spot-free rinses, and minimize equipment maintenance. 
  • Ultraviolet disinfection: This provides an added layer of assurance that you’re getting rid of waterborne pathogens, making the water microbiologically safe.

While these additional filtration processes are optional, they can boost overall customer satisfaction by improving the quality of your washes and give you extra marketing points when working to distinguish your car wash business from the competition.

Reclaimed Water Usage

Once you fully purify the water, you can reincorporate it into your car wash process. Car wash businesses achieve more than cleanliness through the application of reclaimed water for final rinses. They also show their customers they have an unwavering commitment to sustainability, resource conservation, and the delivery of a genuinely unblemished, streak-free, and spot-free finish.

Benefits of Car Wash Reverse Osmosis Systems

From saving money to providing spot-free rinses, car wash reverse osmosis water pays for itself with these seven benefits.

Reduced Mineral Content in Water

Minerals like calcium and magnesium are notorious for causing water spots and streaks on vehicle surfaces. Reducing the mineral content in car wash water through reverse osmosis systems greatly elevates the quality of your car washing services by giving your customers’ vehicles a mirror-like shine.

Beyond aesthetics, reducing mineral content prevents the accumulation of mineral deposits that can damage a car’s paint and surfaces over time. This helps preserve your customers’ vehicles and keeps them coming back again and again.

Efficient Removal of a Wide Range of Contaminants

RO systems are remarkably effective at removing minerals and contaminants from car wash water. Purer water lets you offer customers a more thorough, effective wash. You can provide a spot-free and streak-free rinse, ensuring your customers’ cars look better for longer. 

Minerals and other contaminants can wear your car wash machinery down over time. By targeting contaminants that conventional filtration methods might leave in, RO systems help preserve your equipment and protect your investment. 

Improved Water Quality for Streak-Free and Spot-Free Car Washing

The improved water quality from a spot-free car wash water filter system results in a beautiful car wash finish through:

  • Uniform Evaporation: Untreated water with mineral content can lead to uneven evaporation, whereas the absence of minerals and contaminants means the water applied during car washing evaporates uniformly. This results in a residue-free drying devoid of unsightly water spots that can cause damage over time and customer dissatisfaction.
  • Enhanced Reflectivity: With no mineral deposits to distort the way light interacts with the paint, spot-free water enhances the gloss and reflectivity of vehicle surfaces.
  • Consistency in Results: RO systems consistently deliver high-quality water devoid of minerals, ensuring that each car wash yields the same exceptional results.

Reduced Need for Manual Drying

By incorporating reverse osmosis technology, car wash businesses can reduce the need for manual drying of final rinse water. Once again, the key to this efficiency lies in the unparalleled purity of the water provided by RO systems.

Ordinary tap water contains minerals and impurities that cause water spots and streaks on vehicle surfaces. Without removing these unwanted residues through manual wiping or drying, you can’t achieve a spotless finish.

On the other hand, pure water leaves no mineral deposits as the water evaporates, ensuring an even and uniform drying process. The absence of mineral spots eliminates the need for labor-intensive manual drying, streamlining your operations and reducing turnaround time.

Improved Customer Satisfaction

A spot-free finish, reduced wear-and-tear on a car’s exterior due to washing, a shine that beams after a wash on a sunny day — what’s not to love?

RO-treated water ensures vehicles that emerge from your car wash look flawless, keeping customers happy and coming back. Moreover, satisfied customers will provide great word-of-mouth marketing when they show off their vehicles to friends, family, and colleagues.

Employing a reverse osmosis car wash system will showcase your reliability and deliver consistently outstanding results that build a loyal customer base. 

Compliance With Water Quality Regulations

Between chemicals in car wash treatments and the grime that comes off a vehicle when it’s washed, car wash water gets dirty. And regulators don’t want to see all these contaminants end up in the ocean or local water supply. An example of some of the byproducts of car washing are:

  • Oil and Grease: Oil and grease residues from vehicles can wash into the water during the car wash process, leading to contamination and harming aquatic life and local water quality.
  • Heavy Metals: Some car parts, such as brake pads, contain heavy metals like copper and zinc. As these metals wear off, they can wash into the water, causing pollution.
  • Alkylphenol ethoxylates (APEs): APEs are sometimes used to help break down grease and dirt on surfaces. However, APEs can have negative environmental impacts as they break down into compounds that can harm aquatic life and persist in the environment.
  • Acids and Alkaline Cleaners: Acidic and alkaline cleaners remove specific types of stains, such as mineral deposits. These cleaners can alter the pH of water if not adequately neutralized before being discharged.
  • Solvents: Solvents remove stubborn stains and contaminants from vehicle surfaces. Some solvents can contain volatile organic compounds that, if not managed correctly, can evaporate into the air or leach into water sources, potentially posing environmental risks.

These contaminants are what regulations seek to keep out of the public water supply. To comply with these regulations, you need effective car wash filtration. 

Reduce Water Consumption Bills

By recycling and reusing treated water, your car wash can efficiently pre-rinse, clean, and rinse vehicles without continuously tapping into new water supplies for each step. This significantly reduces reliance on freshwater sources, directly curbing water consumption and lowering water bills.

Additionally, RO systems produce both purified water and reject water streams. While you can use the former for washing, you can further treat or reprocess the latter, drastically minimizing the volume of wastewater that requires disposal and reducing disposal costs. This is especially beneficial if your car wash is in a water-scarce region where water usage rates are high. Reducing your water car wash’s water consumption also shows your customers you’re committed to environmental stewardship.

Improve the Quality of Water in Your Business With NCS Water Recycling Systems

Consumers care more now about sustainability than they ever have before. Touting that your car wash uses recycled water through reverse osmosis is a great way to let them know you care, too. Plus, using water recycling systems can help you save money and deliver top-notch washes that make your customers happy. 

National Carwash Solutions (NCS) can help you with your water recycling needs. We are an end-to-end provider of car wash business supplies and equipment, including E3 series reverse osmosis units and other PurClean™ water-treatment systems that save water, reduce sewer costs by up to 90%, and deliver a pristine spot-free rinse. 

Contact NCS today to discover how our water-recycling car wash systems can help your business thrive. 

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