How Much Water Do You Need To Properly Wash Your Car? (Answered)


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Water savings is becoming more and more popular, especially after this summer’s water restrictions in some states in the USA. Since we all like to clean cars, I decided to share some information on how much water you need to wash your car. 

I’ll concentrate on washing your vehicle at home, but I’ll also give you some information about automatic and self-service car washes so that you can compare the data. 

To wash your car at home, you’ll have to spend anywhere between 10 to 100 gallons of water, depending on the methods you use. The most water-saving way is by using a pressure washer and buckets. 

I know that these numbers are too broad, and that’s why I decided to write this article in the first place. There are just too many factors, and I’ll thoroughly describe them below. So, make sure to read the whole article. 

Important Factor: How You Wash The Car

The most important factor determining water consumption when washing cars is the method you use to clean them. Some people tend to spend as little as 10 gallons, while others need 80+ gallons for a single car wash, which is a real exaggeration.

Professional car detailers (especially mobile ones) know how to wash the car by using very little water. You’ll hardly achieve a well-cleaned car with 10-gallons of water only, while some professional car detailer could (for mid-sized vehicles). 

Factors that affect the amount of water needed to wash the car:

  • Your experience
  • Equipment you use
  • How dirty is the car
  • The method you use for washing

GPM – The Golden Metric

GPM (Gallons per minute) is the most crucial metric for today’s article. GPM accounts for how much water flows through the device or hose each minute. 

By knowing the GPM of your detailing equipment, you’ll quickly understand how much water you need. Just multiply the GPM rate of your device or hose with the minutes you use them when washing the car, and you’ll get an approximate result. 

For instance: you use a 1.8 GPM pressure washer, and you need 4 minutes to pre-rinse the vehicle and 3 minutes for final rinsing. Just multiply the GPM with time spent, and you get the number—1.8×7=12.6 gallons. 

Washing Car At Home

washing car at home with pressure washer

In my opinion, washing your car at home is the best type of wash you can give to your vehicle. By washing a car at home, you can take all your time needed to pay attention to details and clean everything as thoroughly as possible.

Most people wash their cars at home in three ways:

I’ll describe each way of washing your car and show you some average numbers of how much water is needed by each method.

1. With Pressure Washer

Washing your car with a pressure washer is the best way to wash your vehicle at home without spending too much water. Of course, you’ll need wash buckets and a wash mitt, but the main “water” tasks are made with a pressure washer.

On average, you’ll spend anywhere between 10-25 gallons of water to wash a mid-sized car by using a pressure washer. If the car is extremely dirty, you could spend a bit more.

These numbers are the average, and they can go up or down depending on your experience, speed, and the way you wash your car. Most auto detailing pressure washers have a GPM of 1.2-1.8, which is powerful enough but yet great for reducing the amount of water needed to wash the vehicle.

Not only do the pressure washers spend less water, but they’re also more powerful than garden hoses, which means that you’ll wash your vehicle in less time. It’s a win-win situation. 

2. Garden Hose Without Any Attachments

As a kid, I always washed my father’s car by using a garden hose without any attachments, a sponge, and a wash bucket. Back then, I didn’t know any of the auto detailing “rules,” and I was ruining the car’s look by washing it, spending too much water needlessly. 

By using a garden hose without any attachments, you’ll easily spend 80+ gallons of water to wash your car. On average, garden hoses have a GPM rate of 7-10, which is just too much.

As you can see, washing your car with a garden hose only is the least water-efficient method. For instance, when washing a car with a pressure washer for 10 minutes, you’ll spend only around 15-18 gallons, compared to 70-100 gallons when cleaning with a garden hose. 

3. Garden Hose With Attached Sprayer (Nozzle)

If you’re on a tight budget and don’t have goods for a pressure washer, you should at least invest in some garden hose sprayer. These nozzles will make it easier for you to wash the vehicle and reduce the amount of water spent on washing. 

When washing your car with a garden hose sprayer, you’ll spend anywhere between 30-60 gallons of water on average. Most garden hose nozzles have a GPM of 3-6.

As you can see, it’s much better than using a garden house without any attachments. Garden hose sprayers are pretty cheap, and I think everyone should have them at home. 

4. Don’t Forget Car Wash Buckets

Even though I’m concentrating on pressure washers and garden hoses, I can’t write this article without mentioning car wash buckets. As you know, I recommend using a 3-bucket method when washing cars, and it requires some water too. 

If you use a 3-bucket method, you’ll spend another 10 gallons of water per vehicle. You need 2.5-3 gallons of water in each bucket (wash, rinse, wheels).

So, if you spend 10-gallons of water when using a pressure washer, make sure to add another 10 gallons for wash buckets, or 6 gallons if you’ll use a two bucket method. 

Self-Service Car Washes

Self-service car washes are great for you if you don’t have any detailing equipment at home. When I’m in another city, I always use a self-service car wash to wash my vehicle. It’s the safest and most convenient way for me (when not washing my car at home). 

On average, you’ll spend anywhere between 30-60 gallons of water to wash your car at a self-service car wash. 

The biggest con of self-service car washes is that there’s no bucket and wash mitts, and you’ll have to use the wand much longer in order to clean your car properly. 

However, I always bring my car wash bucket and other equipment, which I explained in my thorough guide on How To Wash a Car at a Self-Service Car Wash. 

Washing at Automatic Car Washes

Washing your car at an automatic car wash that uses brushes is one of the worst things you can do to the car’s paint. Even though they promote brushes as “clean” and “safe,” they’re not. My advice is to avoid automatic car washes (tunnels, in-bay, friction, hybrid) at all. 

On average, automatic car washes use anywhere between 30-80 gallons to wash your vehicle, depending on the type of wash and the settings they use. 

Automatic car wash companies always promote their services as the best to save water. Still, you can spend much less water washing your vehicle at home with a pressure washer. 

Final Chart

Here’s a quick table I made so that you can quickly see and compare the average water spendings of each method mentioned in this article. I hope you’ll like it. All numbers are average, for mid-sized vehicles.

MethodWater Needed (Average)
Pressure washer10-25 Gallons (+ buckets water)
Garden hose without attachments80-100 Gallons (+ buckets water)
Garden hose with attachments (nozzles)30-60 Gallons (+ buckets water)
Self-service car washes30-60 Gallons
Automatic car washes (tunnel, in-bay, friction, etc.)30-80 Gallons
Average water needs for specific car wash methods

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