No, jet washing does not remove black spots for good. It blasts off the visible surface so the patio looks clean for a few days, but it leaves the roots of the lichen buried in the stone, and they grow straight back. At Outdoor Butler, the outdoor cleaning specialists across Orihuela Costa, Torrevieja and the Costa Blanca, we see the same cycle every week: jet wash, spots return, jet wash harder, spots return worse. Ask for your free, no-obligation quote: clear prices, no hidden fees.
It is one of the most common questions we get, and the honest answer surprises people. Here is exactly what a pressure washer does to black spot, why it comes back, and what removes it properly.
What jet washing actually does to black spot
Black spots are lichen, a living organism that drives root-like filaments deep into the pores of stone, concrete and terracotta. A jet wash hits the surface with enough force to strip off dirt and the visible top of the lichen, which is why the patio looks transformed on the day. But the pressure never reaches or kills the roots. Within weeks those roots push new growth back up through the same pores, and you are back where you started.
Why jet washing makes black spots come back faster
Here is the part nobody warns you about. High pressure does not just fail to kill the lichen, it actively helps it return. Blasting the surface erodes and roughens it, opening up the pores and micro-cracks in the slab. That rougher, more open surface holds water and traps spores far more easily than a smooth one, so it becomes the perfect nursery for the next generation of lichen. Every aggressive jet wash leaves the patio a little more vulnerable than the last. That is why so many people find the spots return quicker and thicker each year.
What actually removes black spots
The method that works is chemical, not mechanical. You kill the organism at the root, then let it lift away gently:
- Apply a specialist biocide. A dedicated lichen and algae treatment is applied to the dry paving and left to dwell for several hours so it soaks in and kills the lichen at the root.
- Let the weather do the rest. The dead lichen releases its grip and washes away gradually over the following days and weeks, so the surface keeps clearing after treatment.
- Finish with a low-pressure soft wash. A gentle rinse, not a blast, clears the dead growth without eroding the stone or opening the pores.
This is the opposite of jet washing, and it is the reason the results last. We go into the full breakdown in our guide to black spots on your patio and how to fix them.
When is a pressure washer the right tool?
Pressure washing absolutely has its place, just not for black spot. On robust surfaces with ordinary dirt, mud, sand or general grime, a controlled pressure wash is exactly right. The skill is matching the method to the problem and the surface, which on Costa Blanca terraces means knowing the difference between porcelain, natural stone and terracotta, and never using brute force on lichen or delicate materials.
The Costa Blanca angle
Almost every villa owner here has already tried a jet wash, often more than once, and watched the black spots return by the next season. North-facing and shaded terraces are the worst affected because they stay damp longer. If you have been fighting the same spots for years with a pressure washer, the machine is not the answer, and switching to a proper root-kill treatment is what finally breaks the cycle.
Frequently asked questions
Does pressure washing remove black spots from a patio?
Only temporarily. It removes the visible surface but not the roots, so the lichen regrows, often faster because the pressure roughens the stone.
Why do black spots come back after jet washing?
Because the roots stay alive in the pores of the stone. Jet washing only removes the top, and the roughened surface it leaves behind traps moisture and spores that speed up regrowth.
What kills black spots permanently?
A specialist biocide left to dwell so it kills the lichen at the root, followed by a low-pressure rinse. Regrowth is then kept away with occasional preventative treatment.
Can jet washing damage my patio?
Yes. High pressure can erode joints, strip surface finish and open the pores of the slab, which is both cosmetic damage and an invitation for lichen to return.
Ask for your free, no-obligation quote
Stuck in the jet-wash-and-repeat cycle? Let Outdoor Butler break it in Orihuela Costa, Torrevieja and across the Costa Blanca with a treatment that kills black spot at the root. We will give you a free, no-obligation quote with no hidden fees. Message us on WhatsApp at +34 644 466 783 or call +34 644 390 864.