Can I Put Water In My Windshield Wiper? (5 Costly Mistakes To Avoid)


Water in windshield bottle

Winter driving with a low sun in your eyes behind a filthy truck, not the ideal time to run out of washer fluid. Driving in these types of conditions is challenging enough.

So, can I put water in my windshield wiper? Yes, you can use water in your windshield washer in an emergency, but long-term use is not advised. Using water in your windshield wiper reservoir can cause the following problems:

  1. Freezing windshield
  2. Freezing washer components
  3. Bacteria and mould
  4. Washer pump damage
  5. Premature wiper blade wear

In this post, we’ll outline why it’s a bad idea to use water as a substitute for washer fluid. Sure, we’ve all done it when we’re stuck, but you need to use caution, using just water can be an expensive mistake.

1 Freezing Windshield

Frozen windshield

If you live in a cold climate you’ll already know just plain water in the windshield washer can freeze. But even if it doesn’t, using your washer on the windshield in freezing conditions will cause it to ice over.

This as you can imagine is dangerous, especially at highway speeds. The water turns to ice pretty much instantly and the wipers can’t shift it. Add a low sun to the mix and your driving blind, spraying more water makes things worse.

That’s why special anti-freezing washer fluids were developed. However not all washer fluid is anti-freezing, so make sure it states it clearly.

The most common types of washer fluid are:

  • Summer fluid
  • Bug remover
  • All weather
  • Winter Di-Icer

In addition, washer fluid is offered as a concentrate (Typically mixed at 200 to 1) or as a pre-mixed solution that you put straight into the reservoir.

Many fluids will also have a pleasant fragrant added mostly for your pleasure.

Summer washer fluid won’t have an anti-freezing agent added, instead a good quality summer fluid will have a cleaning agent and an anti smear agent, not unlike dishwasher finisher. It may also have a lubricant added to prevent wiper blade skipping and help water runoff.

Bug remover fluid, as you can guess, is a fluid that specializes in clearing bugs from the windshield during the summer months. The fluid is basically a much stronger formula. This fluid won’t have an anti-freezing agent.

All-weather fluid is exactly what you expect, a fluid that does it all, you can use this stuff winter and summer. It cleans to a streak-free finish with -25°F (-31°C) anti-freezing protection.

Winter Di-Icer fluid is designed for extremely cold weather conditions. This fluid will protect from freezing but will also clear windshield ice much quicker than regular all-weather fluid. The Di-Icer has a much higher ratio of anti-freezing agents, methanol, and glycol.

2 Freezing Washer Components

Washer fluid lines

You already know that plain water will freeze in the washer system and when it does, it can do quite a lot of damage. Water, of course, expands as it freezes, the frozen water will crack and break plastic components like pumps, reservoirs, spray nozzles, and hose pipe connectors.

Hose pipes generally escape damage as they’re made from rubber.

Damaged windshield jet

Repairing this kind of damage can be expensive, pumps and reservoirs aren’t hugely expensive but labor can be. Some modern cars will require the front bumper and wheel liner removed in order to gain access.

The way to avoid this type of expense is to use all-weather washer fluid.

3 Bactria And Mould In The Washer

Windshield washer jet

Water in the washer bottle will be heated by the engine and cooled at shut down. This constant cycle is the perfect breeding ground for bacteria and mold to thrive.

Spraying the washer bottle now sends a cloud of bacteria at the windshield but also at the fresh air intake, so the bacteria are entering the cabin.

How do you kill it? Use a good quality washer fluid. Most will have an alcohol content that prevents bacteria and mold development.

4 Washer Pump Damage

Washer bottle

Using just plain tap water all the time in your washer system will clog it up eventually. Chemicals in the water like calcium and limescale (using a kettle to fill the washer system) will jam the pump and clog the fine washer spray nozzles.

Mixing water with the washer fluid is fine as the concentrate has been engineered to work with plain tap water.

5 Wiper Blade Wear

Windshield wiper damage

Water can be hard and leaves a skum on the windshield as it dry’s. This added friction on the windshield causes the rubber of the wiper blades to work harder. Save some dollars and fit your own wiper blades, this post shows you how to buy the correct type and how to fit them “Are wiper blades universal”.

Washer fluid has various additives that clean the windshield but also polish and lubricate it. This as you can imagine allows the wiper blades to just glide across the surface, less friction equals less wear.

The scummy windshield also causes the wipers to skip or shudder across the windshield. If your wipers have been doing this for some time, they’re now worn out.

Your new wipers will last longer and move like butter if you first clean your windshield and then use top-quality washer fluid.

Washer fluid

Related Questions

Soap in the windshield washer? Soap in the windshield washer isn’t advised as it will strip protective wax coatings from the car’s paintwork. Used continuously, it may damage the paintwork and exterior plastic trim.

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty-five years, and I've worked for GM, Volvo, Volkswagen, Landrover, and Jaguar dealerships. My passion is cars. I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of car ownership, including buying advice, maintenance, and troubleshooting.

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