# How quickly should a car be washed after driving on salt treated roads? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [February 19, 2025, 1:08pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502 "2025-02-19T13:08:11Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [February 19, 2025, 5:50pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/21 "2025-02-19T17:50:36Z")
> [@Mighty\_Mouse](#): > > I’ve lived in snowy areas for 27 years and have never worried about salt on my car. Same here. I’m lucky if I get to the car wash more than once in the winter here in Chicago. It’s never been an issue for my cars that I’ve ever noticed, but I’m also not one who really gives a damn on how a car looks. Still, no rusting or pitting or anything that I see on my Mazda 3 I bought in 2015. ---
**Author:** ![a6ka97](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@a6ka97](https://boards.straightdope.com/u/a6ka97)\ **Post date:** [February 19, 2025, 7:11pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/22 "2025-02-19T19:11:26Z")
> [@aceplace57](#): > > Then wipe down the car’s fenders and lower body panels with a sponge and bucket of warm soapy water. Then rinse throughly with fresh warm water. The areas you are washing are not that susceptible to rust due to the paint. The areas susceptible to rust is the underside body pan, suspension/frame, and inner fenders. In order to clean these areas you would need to go to a car wash with an undercarriage wash option. I live in Iowa and will wash my vehicle only 2-3 times during the winter. I only wash it after a week (or more) of snow/ice free weather. I have heard some wash systems, to be more environmentally friendly, will take the final rinse water and use it as part of the pre-rinse and undercarriage wash blasting potentially salty water in to the crevasses of my undercarriage. I want plenty of time between when the "salty’ vehicles go through and when I take mine. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [February 19, 2025, 7:23pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/23 "2025-02-19T19:23:41Z")
I didn’t know they have undercarriage washes up North. I’ve never seen one. It would a nice feature. I can uses the Car Wash pressure hand wand to get under my car. That’s the best I can do. My parents and I lived in Massachusetts for 9 years. I remember my dad driving on the slushy roads. We moved to Arkansas before I learned to drive. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [February 19, 2025, 8:23pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/24 "2025-02-19T20:23:34Z")
> [@aceplace57](#): > > I didn’t know they have undercarriage washes up North. Why wouldn’t we? ---
**Author:** ![Kropotkin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kropotkin/32/18045_2.png) [@Kropotkin](https://boards.straightdope.com/u/Kropotkin)\ **Post date:** [February 19, 2025, 8:32pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/25 "2025-02-19T20:32:17Z")
You got the factory-installed Tru-Coat, right? ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [February 19, 2025, 8:43pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/26 "2025-02-19T20:43:10Z")
Usually the rust starts near the Ziebart or Rusty Jones decal and radiates forward to the hole in the fender for the ignition lock and backward to the fuel cap under the license plate. But by then, the car will have 40 or 50 thousand miles and need a drivetrain overhaul. Don’t forget to buy stem lube, winter’s chill is here for a while. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [February 19, 2025, 8:56pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/27 "2025-02-19T20:56:22Z")
> [@Machine\_Elf](#): > > Why wouldn’t we? A undercarriage wash makes perfect sense. I never saw one, but I don’t live where they’re routinely needed. It would be useful here for trucks that go off road mudding. I’ve gone with a friend and had a blast. It was a prepared trail intended for the sport. He has a pressure washer at home to clean the truck. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 19, 2025, 9:04pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/28 "2025-02-19T21:04:55Z")
High pressure undercarriage wash is specifically advised against for some cars with electronic systems ( eg my Prius Prime). ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 22, 2025, 2:09pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/29 "2025-02-22T14:09:58Z")
IME substantially every automated carwash with the tunnel & big brushes has undercarriage wash as a built-in feature. Doesn’t matter if you’re in a warm or cold climate. Perhaps the OP has a different definition of a “car wash place” than I do. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 22, 2025, 2:59pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/30 "2025-02-22T14:59:18Z")
I think that most cars sold for use in northern climates get a coating on the undercarriage to slow salt-related rusting. But cars sold in the South might not get that. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [February 22, 2025, 3:01pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/31 "2025-02-22T15:01:23Z")
I usually either ride through or go inside the building and meet the washed car on the other end. I’ve only seen the brush wheels on the top and sides. I’ve never noticed any washing on the underside. It could happen and I wouldn’t see it sitting in the car. We had a walk through in my hometown. Guys prepped the car before it went in and other guys dried it and vacuumed on the other end. I could only see through windows in the building. I normally wash my cars in a self-serve with a pressure wand. I bring a bucket and sponge. ---
**Author:** ![Mighty\_Mouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mighty_mouse/32/7776_2.png) [@Mighty\_Mouse](https://boards.straightdope.com/u/Mighty_Mouse)\ **Post date:** [February 22, 2025, 3:04pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/32 "2025-02-22T15:04:12Z")
If you mean Northern and Southern United States (as opposed to USA vs Brazil) this is absolutely not true for at least two assembly plants I know of (one in Georgia the other in Ontario). ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [February 22, 2025, 3:04pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/33 "2025-02-22T15:04:34Z")
> [@aceplace57](#): > > I understand people in the North drive on treated roads daily for several months. It’s not practical to wash away the salt several times a week. Cars are perpetually salty here. I have never really bothered to regularly wash my car - I do it every now and the when it’s really dirty but rishing off to clean it when it’s salty would require 3-4 washes a week. My car has 200,000 KM right now and not a spot of rust. No indication whatsoever of a problem., and my mechanic does very thorough inspections. Cars just don’t rust anymore like they used to, it’s really not much of a risk. ---
**Author:** ![a6ka97](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@a6ka97](https://boards.straightdope.com/u/a6ka97)\ **Post date:** [February 22, 2025, 4:30pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/34 "2025-02-22T16:30:03Z")
> [@aceplace57](#): > > I’ve only seen the brush wheels on the top and sides. I’ve never noticed any washing on the underside. It could happen and I wouldn’t see it sitting in the car. Even in a brush type car wash the undercarriage wash would be a set of high pressure nozzles spraying the underside of the car. The ones I have been through this step is usually at the beginning of the wash. ---
**Author:** ![chela](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chela/32/21582_2.png) [@chela](https://boards.straightdope.com/u/chela)\ **Post date:** [February 22, 2025, 4:48pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/35 "2025-02-22T16:48:10Z")
> [@RickJay](#): > > Cars are perpetually salty here Same here and I also visit car washes infrequently. But I will go mostly to have the encrusted snow pack in the wheel wells hosed off. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [February 23, 2025, 12:31pm UTC](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502/36 "2025-02-23T12:31:01Z")
> [@Mighty\_Mouse](#): > > I’ve lived in snowy areas for 27 years and have never worried about salt on my car. Lived in snowy areas all my life really. Now though, it’s crazy. We have snow from October till April. I haven’t washed my car all winter. When you get snow at least once a week, and the nearest car wash is 15 miles away (on snow covered roads) it’s a bit of a fools errand to wash it. [Previous page](https://boards.straightdope.com/t/how-quickly-should-a-car-be-washed-after-driving-on-salt-treated-roads/1014502.md?page=1)