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  • Writer's pictureJessica Dumais

What Are Those Orange Yellowish Stains on My House Exterior Walls?

Updated: Feb 5, 2023

Sulfur rust stains on house exterior walls
Sulfur stains on walls, garage door, driveway, and sidewalks

It's finally this time of the year. It is winter and it's time to clean up! This week, I have been seeing pressure cleaning companies left and right. However, what those professionals are not sharing with my lovely neighbors is that pressure cleaning will not remove those ugly, nasty, orange spots found on the house exterior walls, driveways, sidewalks, and fences.

What causes those sulfur rust stains? The short answer is: well water irrigation systems. Hard water (non-treated water) contains lot's of minerals such as iron and sulfur. When the sprinklers hit the house while operating, over time, it leaves permanent stains which are far from being appealing...

Now, I use the word "permanent" because it is in fact extremely hard to remove those stains and pressure cleaning the house exterior with water is simply not enough. Special formulated chemical treatment might be your only option to get rid of them.

So, How to avoid these stains?

1. Adjust the sprinkler heads, so that the water does not hit the house or anything else.

2. Treat well water to reduce sulfur and iron concentration.

3. Use filtering or water softening systems.

4. If possible, use city water to water your grass instead!

To conclude, sulfur rust stains are not going away with a simple surface pressure cleaning. They require special chemical treatments that can be applied by trained professionals. Prevention is key. Position the sprinkler heads properly, use a filtration system, and you will have nothing to worry about.

Happy cleaning!

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