It is a genuinely deflating experience. You pay to have the driveway cleaned, and when it dries it looks patchy, striped or oddly mismatched — worse, somehow, than the uniform grey you started with.
There are three explanations, and it matters which one you have.
1. Tiger striping — the most common by far
Wavy light and dark bands across the slab, often in overlapping arcs. This is a tool problem, not a technique problem.
A handheld wand concentrates all its pressure into a narrow fan. Wherever the operator paused or moved slowly, the concrete got cleaned deeper. Wherever they moved quickly, it did not. Because the difference is in how much surface layer was removed, it does not fade — the marks are still there in three years.
Can it be fixed? Yes. The whole slab has to be cleaned again, properly, with a rotating surface cleaner that applies even pressure across its full width. That brings everything down to the same level and the stripes disappear. It is the same job you already paid for, done with the right equipment.
2. The dirt was hiding a mismatch
This one is nobody's fault, and it surprises people.
Concrete poured at different times cures to different shades. Patch repairs, a replaced apron section, a trench cut for a utility line, an addition poured a decade later — all of it produces colour variation. A uniform layer of grime hides that beautifully. Remove the grime and the slab shows its actual history.
It is especially common on older Westside and Arlington driveways, where sections have been replaced over forty or fifty years.
Can it be fixed? Not by cleaning. The options are a concrete stain or overlay to unify the colour, or accepting it. A good contractor flags this before starting when the mismatch is visible in advance.
3. Surface erosion from too much pressure
The serious one. Concrete has a smooth cement-rich paste at the surface and coarser aggregate underneath. Excessive pressure — particularly on newer concrete that has not fully cured, or older concrete that is already weathered — blasts that paste away and exposes the aggregate.
The result is a rougher, more porous surface that looks lighter, feels gritty, and holds dirt worse than it did before. It also picks up new staining faster, so the driveway will need cleaning more often from now on.
Can it be fixed? No. The removed material is gone. A resurfacing overlay is the only genuine remedy, and that is a concrete job rather than a cleaning one.