Why Houses Turn Green So Fast in St. Tammany Parish (And What You Can Do About It)

Have you ever looked at your home one day and thought…

“I swear this house wasn’t this green a few months ago.”

You’re not imagining it.

If you live in Mandeville, Covington, Madisonville, Abita Springs, Slidell, Lacombe, Hammond, Ponchatoula, Robert, or anywhere across Southeast Louisiana, your home is constantly battling one thing:

Louisiana’s climate.

Our combination of heat, humidity, heavy rainfall, and abundant tree cover creates the perfect environment for algae, mold, and mildew to grow on nearly every exterior surface.

The good news? It isn’t permanent—and with professional soft washing, your home can look like new again.

It’s Usually Not Mold… It’s Algae

Many homeowners assume the green color on their siding is mold.

In reality, it’s usually algae.

Algae spores are carried through the air every day. Once they land on your home’s siding, brick, stucco, soffits, gutters, or trim, they begin feeding on moisture and organic material.

Because Southeast Louisiana stays humid for much of the year, algae rarely has a chance to dry out completely.

That means it continues growing month after month.

Why Homes in St. Tammany Parish Get Green Faster Than Other Areas

There are several reasons homes here become dirty much faster than homes in other parts of the country.

High Humidity

Humidity is one of algae’s best friends.

Even when it hasn’t rained in days, morning dew and high overnight humidity leave your home’s exterior damp enough for algae to continue growing.

Frequent Rain

Our area receives well over 60 inches of rainfall each year.

Rain provides the moisture algae needs while also carrying airborne spores onto your home’s exterior.

Mature Trees

One of the things people love about neighborhoods like Beau Chêne, Old Mandeville, Covington, and Madisonville is the beautiful mature oak trees.

Unfortunately…

Those same trees create shade.

Shaded walls stay damp much longer after rain, allowing algae to spread faster than sunny areas.

Warm Temperatures Nearly Year-Round

Unlike northern states, Louisiana rarely experiences long freezing periods that naturally slow biological growth.

Algae simply keeps growing.

Areas That Usually Turn Green First

You’ll often notice algae appearing first on:

North-facing walls
Shady sides of the home
Vinyl siding
Stucco
Brick
Fascia boards
Soffits
Gutters
Fences
Retaining walls

If left untreated, the staining gradually spreads across the rest of the home.

Is Pressure Washing the Right Solution?

Not always.

Many homeowners think higher pressure means better cleaning.

Actually, excessive pressure can damage:

Vinyl siding
Stucco
Painted surfaces
Window seals
Wood trim
Mortar joints

That’s why Wash Hawk uses a professional soft washing process.

Instead of relying on high pressure, soft washing uses specialized cleaning solutions and low-pressure application to eliminate algae at the source.

The result is a deeper, longer-lasting clean that’s safe for your home’s exterior.

Can I Prevent My House From Turning Green?

While no home can completely avoid algae in Louisiana’s climate, there are several ways to slow it down.

Trim Back Trees

Allowing more sunlight onto your home’s exterior helps surfaces dry faster.

Keep Gutters Flowing

Overflowing gutters keep siding wet and encourage algae growth.

Regular gutter cleaning helps reduce excess moisture.

Schedule Routine House Washing

Most Louisiana homes benefit from professional house washing every 12–18 months.

Regular maintenance prevents heavy buildup and keeps your home looking its best year-round.

More Than Just Better Curb Appeal

A clean home does more than impress your neighbors.

Professional house washing can help:

Protect paint and finishes
Reduce long-term staining
Improve curb appeal
Remove slippery organic growth
Increase pride of ownership
Help maintain your home’s value

Frequently Asked Questions About House Washing in Louisiana

Why does my house turn green so quickly in Louisiana?

Louisiana’s warm, humid climate creates ideal conditions for algae, mold, and mildew to grow on your home’s exterior. Frequent rainfall, high humidity, and shaded areas allow algae to thrive on siding, brick, stucco, soffits, and gutters. Homes in St. Tammany Parish, Tangipahoa Parish, Jefferson Parish, and Orleans Parish often experience faster algae growth than homes in drier climates.

Is the green on my siding mold or algae?

In most cases, the green discoloration on your siding is algae, not mold. Airborne algae spores settle on your home’s exterior and feed on moisture and organic material. While mold can also grow outdoors, algae is far more common on siding throughout Southeast Louisiana.

Can I pressure wash algae off my house?

While pressure washing may remove some visible algae, it doesn’t always eliminate the root of the problem. High pressure can also damage vinyl siding, stucco, painted surfaces, and wood. Professional soft washing uses specialized cleaning solutions and low-pressure application to safely remove algae at its source, providing longer-lasting results.

What is the difference between soft washing and pressure washing?

Pressure washing relies on high water pressure to blast away dirt and stains. Soft washing combines biodegradable cleaning solutions with low-pressure water to kill algae, mold, mildew, and bacteria without damaging delicate exterior surfaces. For most homes in Louisiana, soft washing is the safest and most effective method for house washing.

How often should I have my house professionally washed?

Most homes in Southeast Louisiana benefit from professional house washing every 12 to 18 months. Homes surrounded by mature trees or located in heavily shaded areas may require more frequent cleaning due to increased moisture and algae growth.

Will house washing damage my siding?

When performed correctly, professional soft washing is safe for vinyl siding, painted wood, stucco, Hardie board, brick, soffits, gutters, and other exterior surfaces. Wash Hawk uses low-pressure cleaning methods specifically designed to protect your home while delivering outstanding results.

Does house washing increase my home’s value?

A clean exterior significantly improves curb appeal and helps create a positive first impression. While house washing doesn’t directly increase market value, it can make a home more attractive to potential buyers, help maintain exterior finishes, and demonstrate that the property has been well cared for.

Can house washing help if I’m selling my home?

Absolutely. A professionally cleaned home stands out in listing photos and during showings. Removing algae, mildew, dirt, and stains instantly improves curb appeal, helping buyers see the home at its best. As both an exterior cleaning company and a real estate professional, Wash Hawk understands how important first impressions are when selling a home.

How long does professional house washing last?

Most professionally soft-washed homes stay clean for 12 to 24 months, depending on tree coverage, shade, weather conditions, and the surrounding environment. Homes in heavily wooded neighborhoods may see algae return sooner than homes with more direct sunlight.

Why Homeowners Across Southeast Louisiana Choose Wash Hawk

At Wash Hawk, we understand Louisiana homes because we clean them every day.

Our professional soft washing system safely removes algae, mold, mildew, pollen, dirt, and organic buildup without exposing your home to unnecessary high pressure.

Whether you live in:

or anywhere throughout St. Tammany, Tangipahoa, Jefferson, or Orleans Parish, we’re ready to help restore your home’s curb appeal.

Ready to Make Your Home Look New Again?

If your siding has started turning green, don’t wait until the staining becomes difficult to remove.

Wash Hawk offers free, no-obligation house washing estimates throughout Southeast Louisiana.

Our professional soft washing process safely restores your home’s appearance while protecting the surfaces underneath—so you can enjoy a cleaner, brighter home without the risks of excessive pressure.

Call us today or text us at 985.869.0808. Or visit us online at www.washhawk.com

Why Houses Turn Green So Fast in Louisiana | Wash Hawk Softwash