Homeowner Guide

Why Does My Concrete Have White Staining?

A chalky, white, powdery residue on a driveway, patio, or foundation wall is called efflorescence, and it's one of the more common questions Oregon homeowners ask. It looks alarming, but in most cases it's a cosmetic mineral deposit rather than a structural problem — though there are exceptions worth knowing about.

What's Actually Happening

Efflorescence forms when water moves through concrete and carries dissolved salts (naturally present in the concrete or the soil beneath it) to the surface. As the water evaporates, it leaves the mineral salts behind as that white residue. It's essentially the same process as mineral deposits forming around a leaky faucet, just happening inside the concrete instead.

When It's Just Cosmetic vs. When It's a Signal

Light efflorescence on new concrete (within the first year or two) is extremely common as the slab cures and is almost always cosmetic — it can usually be brushed or pressure-washed off, though it may return until the concrete fully cures. What's worth paying more attention to: efflorescence that keeps returning heavily year after year on the same spot (can indicate persistent water intrusion through that area), efflorescence paired with visible cracking or spalling (the surface flaking or peeling away), or heavy staining on a basement or foundation wall specifically, which can point to a drainage or waterproofing issue worth addressing at the source rather than just cleaning the surface repeatedly.