Where it comes from
Dover sits directly beneath chalk downland and the White Cliffs, a soft sedimentary rock that erodes and sheds fine particles more readily than harder stone. Wind and rain carry that chalk dust down onto nearby roads, driveways and paths, where it settles as a pale, sometimes almost powdery film - most noticeable on dark tarmac or block paving, where the contrast is highest.
Why it's different from normal driveway grime
Ordinary driveway dirt is mostly organic - algae, moss, tyre residue, general atmospheric grime. Chalk dust is mineral, fine, and alkaline. It tends to sit on the surface rather than bond into it the way oil staining does, which is actually good news: it usually lifts with a standard high-pressure wash rather than needing a specialist chemical treatment. The catch is that on a badly affected driveway near the cliffs or downland, it can reappear faster than a typical clean would suggest, simply because the source is ongoing, not a one-off.
What actually helps
A standard high-pressure wash at the right level for your surface (see our pricing page for per-surface rates) clears chalk residue effectively. For properties that get it worst - generally those closest to the downland or cliff edge - a protective sealant applied after cleaning (see the add-ons on our pricing page) can slow how quickly it settles back in, the same way sealant helps against oil staining or moss.
What to watch for
If chalk dust is combined with heavy rain runoff, it can leave a slightly gritty residue rather than a clean surface after washing - a second lighter pass usually clears this. It's also worth checking gutters and drainage near cliff-adjacent properties, since chalk sediment can build up there too, though that's outside what we cover.