How to Remove Algae From Vinyl Siding

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Things You'll Need

  • Paper towels

  • Bucket

  • Dishwashing detergent

  • Scrub brush

  • Garden hose

  • Cloth

  • Oxygen-based bleach

Vinyl siding can provide the exterior of your home a fresh, clean appearance and requires much less maintenance than paint. However, vinyl siding that is left damp can result in the growth of unsightly algae. Algae growth is most common in areas that are shaded and, due to the lack of sunlight, remain damp for longer periods of time after it rains. If you find algae growth on your vinyl siding, you can avoid expensive professional treatments by removing the algae on your own.


Step 1

Wipe away as much of the algae as you can with paper towels. This prevents the residue of excess algae from running down the side of the house when it is washed, potentially causing a stain. Paper towels are rough enough to pick up the algae and are disposable so you do not have to worry about staining a cloth.

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Step 2

Fill a bucket with warm water and dishwashing detergent. Mix the detergent into the water until it begins to foam.

Step 3

Spray the affected area lightly with the garden hose.

Step 4

Use a brush to scrub the algae from the surface of the vinyl siding. Take care to get as little soap as possible beneath the siding.


Step 5

Rinse the cleaned sections of siding with a garden hose as you go to prevent the soap from drying on the vinyl. This can leave the siding with a chalky appearance. It is also imperative that you rinse the siding from above, as this is the primary way vinyl siding is designed to repel water.


Step 6

Dry each section of siding well with a clean cloth after washing it. This removes any residual soap residue and prevents the siding from remaining damp after cleaning--a condition that could result in further algae growth.

Step 7

Use an oxygen-based bleach to treat any algae stains that remain after washing.


Clean the siding from bottom to top to avoid leaving streaks.

Clean small areas at a time.


Never use standard commercial bleach to kill algae on a home’s exterior or to treat stains on vinyl siding. Standard bleach will poison any surrounding grass and plants.

Do not use a forceful spray of water from the hose when cleaning your siding. This may cause water to build up beneath the siding and swell over time.

Do not pressure-wash your house to remove algae. This could void the warranty on your vinyl siding.


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