How Often Should You Pressure Wash a Patio or Driveway?

For most UK patios and driveways, a full pressure wash once a year, typically in spring, is enough to keep algae, moss and general grime under control without over-stressing the surface. Shaded, damp, north-facing areas that stay wet and grow algae or moss faster may benefit from a second, lighter clean later in the year.

Why once a year is usually right

UK weather — frequent rain, mild temperatures, and plenty of shade from trees and buildings — creates ideal conditions for algae and moss to establish on outdoor paving. Left too long, these become slippery (a genuine safety hazard, especially in wet or frosty weather) and harder to remove. But pressure washing itself gradually wears surfaces and can strip jointing sand or mortar if done too frequently or too aggressively, so more isn't automatically better. Once a year strikes a reasonable balance for most gardens.

Signs it's time before your usual schedule

• Visible green or black algae/moss build-up, especially in shaded or damp corners.
• The surface feels slippery underfoot when wet.
• General accumulated grime, tyre marks (driveways) or organic staining that a sweep won't shift.

Signs you're overdoing it

• Jointing sand or mortar visibly washing out between cleans.
• Surface texture looking rougher or more worn than it used to.
• Colour fading noticeably faster than expected on coloured block paving or resin surfaces.

Factors that change the ideal frequency

• Shade and damp: a north-facing patio under trees will need cleaning more often than a sunny, open driveway.
• Surface material: softer natural stone benefits from less frequent, gentler cleaning than more robust concrete block paving.
• Nearby vegetation: overhanging trees dropping leaves, sap or berries accelerate staining and algae growth.
• Traffic: a driveway used daily by vehicles picks up oil and tyre residue faster than a rarely-used path.

Between full cleans

A quick sweep to clear leaves and debris, and treating any early moss or algae patches with a suitable moss killer, can extend the time between full pressure washes and reduce how aggressive a clean you need when you do get the pressure washer out. See our companion guide on how to pressure wash a patio without damaging it for the right technique when you do clean.

Common mistakes

• Pressure washing every few months just in case. Accelerates wear and washes out jointing material unnecessarily.
• Leaving it several years between cleans. Built-up algae and moss become genuinely slippery and much harder to remove without aggressive cleaning that risks surface damage.
• Not treating moss/algae at the source. A shaded, damp area will simply regrow moss quickly after cleaning unless the underlying dampness or shade is addressed where practical.

Regional and seasonal factors

Gardens in wetter parts of the UK, or those that see more shade and rainfall through autumn and winter, will generally need cleaning more proactively than drier, sunnier spots. Spring is the popular choice for a full clean because it clears away the accumulated grime and algae from a damp winter before the garden gets full use over summer — but if a particular area struggles year-round, there's nothing wrong with adjusting the schedule to suit what you're actually seeing rather than following a fixed calendar date.

A patio that keeps sinking or cracking despite regular cleaning may have a drainage problem beneath the surface rather than just a dirty one on top — see our guide on why patios sink or crack for the difference.

Driveways vs patios — different wear patterns

Driveways generally need more attention to oil and tyre residue than patios do, since vehicle use introduces staining that garden use doesn't. Patios, on the other hand, often see more organic staining and algae growth from overhanging plants and general garden use. Both benefit from the same basic principle — clean before build-up becomes established rather than waiting until it's very visible, since fresh grime and light algae are considerably easier to shift than growth that's had months to establish.

A simple maintenance checklist

• Sweep leaves and debris weekly during autumn to prevent staining building up.
• Spot-treat any early moss or algae patches as soon as you notice them.
• Check drainage isn't pooling water on the surface after rain, which accelerates dirt and algae build-up.
• Plan a full pressure wash for spring unless a specific shaded area needs attention sooner.