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Making your own windshield wiper fluid


Is there a recommended formula for homemade windshield fluid? From what I understand Wiper Fluid you purchase in the auto store contains some bad stuff, as far as poisons. I also understand you don’t want to just use water, as bacteria can grow in the tank. Is there a combination of dish soap, window cleaner, alcohol that will make a good formula, in warmer climates where freezing is not an issue?

I see a number of posts on this subject, but no clear consensus on the formulas.


What I do when I want to know what stuff is made of, I pick a product and go to the manufacturer’s web site and look up the MSDS (Material Safety Data Sheet), They are required to publish these for poison control and it will tell you everything that’s in it. It won’t give you the exact proportions however.

I’ll go a little off topic . . .

Why do you want to make your own washer fluid?

To save money?

Or to save the environment?


From what I understand Wiper Fluid you purchase in the auto store contains some bad stuff, as far as poisons.

So don't drink it.

Washer fluid contains Methanol..methyl alcohol. This is the stuff that killed people/made them go blind during prohibition. Even today, you get people dumb and/or desperate enough to drink ANYTHING with the words "alcohol" in it.

Given that, when the label says "POISONOUS," translate that to "DO NOT ATTEMPT TO DRINK." When it goes on to say "CANNOT BE MADE NON-POISONOUS," translate that to "AND NO, YOU CAN'T MAKE IT SAFE BY RUNNING IT THROUGH A STILL OR SOMETHING."

As far as environmental exposure, the methanol in washer fluid evaporates quickly after use, so the only impact is a VERY small VOC emission...not going to harm the environment!

Windshield washer fluid contains denatured alcohol which is poisonous if you ingest it. It’s harmless used as a washer fluid. I use it in the winter but use water in the summer. Water actually works better for me in warm weather. It doesn’t evaporate as fast giving it more time to work in removing bugs.

I made plans at one time to counterfeit pennies. I think my idea would have worked, but it would cost me 6.43 cents for each penny I turned out. I think the same would be true if you made your own windshield washer fluid. Obtaining the ingredients would be much more expensive than buying a jug;

Do not use tap water. Do not use tape water. Do not use tap water.
It can contain small particles of sand and other things that plug up the jets that spray the water.

If you don’t use tap water and buy a gallon of distilled water, this really raises the cost of homemade windshield washer fluid.

I am just having a hard time deciding if this thread was started as a trolling attempt…or not.

As was said, the risk to the environment from commercial WW fluid is minimal–at most.
And, if “poisonous” refers to the consequences from drinking WW fluid, then this issue is more than any of us are capable of helping the OP to deal with.

Additionally–as Triedaq pointed out–making your own WW fluid is likely to cost just as much–if not more–than buying the commercial stuff.

I used to go to the beach with and old washer fluid jug. I had cleaned it out and filled it with tap water and blue food coloring. I would sit on the beach swigging it, and watch people’s reactions.
Call me evil.

You’re the guy driving 55 in the left lane with the straw hat too? I make washer fluid the same way I cook supper, I go down to the store/restaurant. My wife asks why I don’t cook supper and I say I do, I just go pick it up is all.

My wife uses white vinegar as her windshield washer fluid. It works for her and cleans the windshield but I can’t get past the smell. It’s probably safe as well. I just buy mine where I buy gas…you know…the blue stuff.

melott – “don’t use tap water”

Depends on your tap water. I have my own well with a particulate matter filter on it. Never had a problem.

In the summer, I use 1 part Windex, 3 parts tap water.

The stuff that makes windsheild washer fluid not freeze in the winter is… Taa Daaa, methyl alcohol or methanol. That’s the bad stuff, but only if you drink it. Windex has ammonia in it (I think it still does) and that can kill you too if you drink a bunch. Just buy it, the commercial stuff is as safe as windshield washer fluid can be. Worry about what comes out your tailpipe if the engine and its systems are not in good tune.

Ticks me off to see a “Save the Environment” sticker on a 71 VW Microbus belching smoke and leaking like the Exxon Valedez!

I avoid water bills by synthesizing my own from the hydrogen/oxygen constituents. It ain’t cheap, but it’s the principle of the matter. Can’t trust public water, what with fluoride and who knows what other secret ingredients.
And of course if you want something done right you just gotta do it yourself.

Speaking of those old VW buses . . .

yesterday on the freeway, there was a guy driving one of those, acting like a total maniac

He was cutting in and out, without using the turn signals, and he wasn’t even turning his head to look what was next to him. Like he owned the road, and everybody else was just inconveniencing him

I truly wished he would have gotten clipped by a Freightliner

I got a good natural fluid to use - vodka! Anti freeze built in!

Drink enough and all those smushed bugs just don’t seem so important anymore.


I really think there are far more important things to put your time and effort into.

At 3-4 dollars for the top brand and maybe using 4 gallons a year per car…it’s just not worth the effort.

How about finding a little road that has a lot of garbage in the ditches and take a nice walk while picking up garbage. I have three that I maintain. My sciatica is so bad that I have to sit down every 100 yds and rest, but I cover the whole length of each road where the road goes thru the state forest. I rely on the property owners to do in front of their land, but I do the rest. I think the longest is just over 2 1/2 miles.
For some reason I’ve taken a liking to these little spots, maybe it’s because they are spots that I use frequently as rest spots for lunch or while waiting for my next client’s appointment. I’ve gotten sick of the trash and decided to take it upon myself to do my part.

When ever I take a walk in the woods…or when I hunt…or scout for hunting, I also take a couple of bags (like from the grocery) and always come back with at least one full of bottles, cans, wrappers, paper, old birthday baloons etc…

Make a difference.