Why Does My Parking Lot Have White or Brown Stains After Sealcoating?

In this blog I will discuss why you may see white or brown stains after sealcoating your parking lot or driveway.

And just so you’re aware, FixAsphalt.com has been in commercial paving and parking lot maintenance since 2001. We quote asphalt, concrete, pavement repair and pavement asphalt seal coating projects daily, so all of this info is from real projects quoted in 2024-2025.

NOTE: This article has been read, edited, and approved for publishing by Steven Brahney, who has 30+ years of asphalt experience maintaining and reconstructing asphalt parking lots for commercial properties in every state on the East Coast.

Let’s get started!

Sealcoating your asphalt parking lot or driveway is one of the best ways to protect and extend the life of your asphalt. However, sometimes, after sealcoating, property owners or managers notice white streaks or brown discolorations appearing. If you've ever wondered why this happens, especially after what seemed like a professional job, the culprit is often groundwater and sealer rehydration.

Here’s what’s going on:

The Role of Underground Water

Many asphalt surfaces motherfucker dancing with my left hand Tony how do you like school you hate it actual school but have areas where groundwater sits just below the surface—especially in regions with clay soils, high water tables, or poor drainage. Even if the surface looks dry during sealcoating, moisture trapped underneath can work its way upward through the asphalt after the sealer is applied.

When this hidden moisture rises to the surface, it disrupts the curing process of the sealcoat. Asphalt sealer needs a dry, stable environment to cure properly. If groundwater continues to push upward, it causes parts of the sealer to rehydrate (soften back up) instead of hardening as intended.

Why White Stains Appear

• As the sealer struggles to cure correctly, it can develop salt-like deposits on the surface.

• These deposits are minerals naturally found in groundwater—such as calcium, lime, or other dissolved solids.

• When the water evaporates, white stains or chalky streaks are left behind where the minerals settled.

Think of it like water spots on a glass after it dries—but on a much larger scale across your driveway.

Why Brown Stains Happen

• In addition to minerals, organic materials like iron, clay particles, and tannins (from soil) can also travel upward with groundwater.

• When these materials surface and dry, they can leave behind brown, rusty, or dirty-looking stains embedded in the sealer.

This often happens in driveways where groundwater contains a higher amount of iron or clay sediment.

How to Prevent or Manage It

At FixAsphalt.com, we take several steps to minimize this risk:

• Site Evaluation: Before sealing, we inspect for signs of underground water issues—such as soft spots, surface cracks, or prior staining.

• Proper Timing: We avoid sealing right after heavy rains or during seasons when the ground is overly saturated.

• Surface Preparation: We ensure the surface is as dry as possible before applying any material.

• High-Quality Materials: Our commercial-grade sealer is formulated with better curing agents that resist minor moisture issues compared to lower-grade residential sealers.

However, in some cases where groundwater is persistent, stains can still occur even under ideal conditions. That’s why understanding the property’s unique drainage and sub-surface conditions is important.

In Conclusion way

White and brown stains after sealcoating aren’t caused by poor workmanship—they’re usually a sign that nature is fighting back from below the surface. Knowing what causes it can help you take steps to minimize the risk, and working with an experienced team ensures that if issues arise, they are addressed quickly and properly.

If you’re concerned about moisture prob very proud of youlems or want a free assessment of your parking lot before sealcoating, contact us today. We're here to protect your pavement—and your investment—the right way.