Does Power Washing Damage Concrete?

Pressure washers are very useful tools that can be used to wash some of the most difficult surfaces. But you do need to be very careful when washing certain types of materials.

Too often, homeowners go to their local hardware store to grab a pressure washer for cleaning jobs at home with little knowledge of how powerful the power washer is.

Some power washers are powerful enough to quickly slice through a watermelon. They can even cause serious damage to a person’s body.

Whenever setting out to power wash a new surface, check to ensure you are using the right settings and following the right steps to avoid damaging the surface you’re trying to clean, like concrete.

Does using a pressure washer on concrete damage it?

No, pressure washing does not damage concrete providing the surface has not already been damaged. If there are any cracks or holes in the concrete you should cover the damaged area up or avoid washing and never spray too close to the concrete as this can leave visible pressure washer streaks behind.

Read on to find out some of the things you can and can’t wash with your pressure washer and how you would go about repairing any damage that may have occurred from pressure washing your concrete.

Outdoor floor cleaning with power washer pressure washer

How often should I pressure wash concrete?

The ideal timespan to pressure wash concrete is once every year, this should be done in the summer months allowing the water to evaporate quite quickly.

Standing water can be really bad for your concrete and can eventually start penetrating the surface and resting deep within the concrete.

Washing your concrete once a year should keep it looking new and remove any grime, dirt, oil, or stubborn stains. It’s a good idea over the long term to ensure your pressure washer hasn’t lost any pressure.

What should I use to clean my concrete?

Before using your pressure washer you should spray your concrete with a degreaser, this should be worked into the concrete with a yard brush.

If you have a particularly stubborn area you can buy attachments for your pressure washer that go on the end of the wand.

These attachments have hard-wearing bristles that allow you to scrub as well as power wash, ideal for oil, grease, and grime.

You may want to consider getting a different pressure washer size depending on how much concrete you need to use one for.

How do I get rid of pressure washer streaks and lines?

Pressure washer lines are created when the operator has held the end of the wand to close to the area, and the pressure creates lines in the concrete surface.

The lines left behind from pressure washing are not damaging to your concrete but can look quite unsightly.

To remove the lines you will need to use muriatic acid on the affected area, using a hard brush to quickly rub into the area and remove the streak.

The acid needs to be removed straight away using water as it is very caustic can actually damage the concrete.

Another way of removing pressure water streaks is to sand the area down using low grit sandpaper, in a circular motion. 

Unfortunately, this can also cause damage and should be done in a limited fashion, again using water to wash the area after using it.

Can I use bleach on concrete?

Yes, bleach can be used directly onto concrete and will not damage the area, but you should never use bleach if you have painted your concrete as it could discolour.

Bleach is particularly useful when trying to remove stains from oil spills, pour onto the stain, and use a hard brush in a circular motion. 

You should always use bleach in a well-ventilated area and make sure that the area is rinsed well afterward.

Remember to use the correct personal protective equipment when using bleach as it can be very hazardous to health and can damage clothing.

Why you shouldn’t pressure wash damaged concrete

If the concrete has already received damage and you then try to pressure wash the area you may find that the force of the water manages to get into the concrete, over time this will cause the concrete to become brittle, crack or crumble.

Below the finished area of a concrete surface, the concrete is very porous allowing water to settle amongst it.

During winter months the water inside the concrete can freeze and expand, this in turn causes stress on the concrete and damages it.

If you have an area that you still wish to pressure wash but it does have damage, you should cover the damaged areas over before you start washing or avoid the damaged area altogether.

Sealing your driveway

If you are thinking about pressure washing a concrete driveway it might be a good idea to seal the surface first.

Sealing creates a protective barrier between the elements and the surface and can help protect your driveway for 3-4 years.

If you have any damage in your driveway the sealer will stop any water from getting into the concrete.

Prior to sealing you should make sure that the area is clean and swept, and all debris removed, you apply sealer like paint using a roller.

Sealing your driveway should be done in the summer months and applied before noon, allowing the sealer to dry other the space of a couple of hours.

Use a paintbrush to get into corners and areas where the paint roller cannot get to.

Re-sealing should be performed every 3 years, this keeps your concrete clean and limits the damage done from the pressure washer and the elements.

Does pressure washing damage bricks and paving slabs?

Extra care should be taken when pressure washing anything that has mortar as a bonding method.

Pressure washers operate at very high pounds per square inch (1400-2300 PSI) this can easily dislodge mortar and concrete from between pavements and bricks.

To prevent this you should seal any mortar prior to washing it. If you don’t have any sealer another option would be to adjust your pressure washer nozzle to a fine spray or mist, this minimizes the pressure and limits any damage done. 

You could also stand at least 3 meters away from the area you are cleaning, again limiting the pressure.

These tips should be tweaked and applied when using pressure washers with other surfaces like decks.


Using a pressure washer on your concrete is a great way to keep the area looking new and is very beneficial to keep your concrete maintained.

You must never pressure wash any damaged areas as this can add to the damage, these areas should be treated or avoided altogether.

When pressure washing brickwork or paving, extra care, and attention should be used around the mortar as the pressure from the washer can easily disrupt or remove it.