What Causes Black or Green Spots on Sidewalks?
By Goliath Softwash
If you’ve noticed black or green spots forming on your sidewalk, you’re not alone. These unsightly stains can make even the most well-maintained property look dirty and neglected. But what causes them — and how can you get rid of them for good?
What Are These Black or Green Spots on My Sidewalk?
Most often, these spots are caused by:
Algae – especially in shady or moist areas
Mold or mildew – common in humid climates
Black algae or lichens – more stubborn and deeply rooted
Organic buildup – from decaying leaves or dirt
These contaminants thrive in areas with little sunlight, moisture buildup, and poor drainage — making sidewalks the perfect target.
Are These Spots Harmful?
Besides being an eyesore, algae and mold can make surfaces extremely slippery, increasing the risk of slips and falls. They can also degrade concrete over time, causing long-term damage if left untreated.
Can I Remove Them Myself?
You can try DIY methods like scrubbing with bleach or vinegar, but these solutions often only treat the surface. Without professional-grade tools or detergents, the growth usually returns in a matter of weeks — especially black algae, which is notoriously hard to remove.
How Can a Professional Help?
At Goliath Softwash, we use a specialized soft washing system that targets and eliminates mold, algae, and lichens at the root. Unlike high-pressure blasting, our method is safe for concrete and leaves surfaces cleaner for longer.
How Often Should I Treat My Sidewalk?
We recommend an annual or semi-annual soft wash, depending on your environment. This keeps walkways clean, safe, and looking like new.
Conclusion
Black and green spots on sidewalks are more than just a cosmetic issue — they’re signs of organic growth that can be hazardous and damaging. Trust Goliath Softwash to eliminate these stains safely and thoroughly, restoring the beauty and safety of your property. Don’t wait for the stains to spread — call us today and bring back your curb appeal!