Pressure Washing vs Soft Washing: Which Is Right for Your Surface?

Pressure washing vs soft washing comes down to one question: is the dirt best removed by force or by a cleaning solution? Pressure washing uses a strong jet of water to blast grime off hard surfaces like concrete. Soft washing uses low pressure and a diluted cleaner that breaks down mould and dirt, then rinses it away gently.

As a rule, hard and sound surfaces such as concrete driveways and paths suit pressure washing. Painted walls, render and other surfaces that can chip, strip or let water in suit soft washing. At Aussie Duo Cleaning Service, our high pressure cleaning team uses both methods across Canberra and Queanbeyan, and picks the method after checking the surface.

Pressure washing relies on water pressure. The jet lifts dirt, grime and loose growth from the surface. On large flat areas, a rotary surface cleaner spins the jets under a cover, so the clean is even and there is less spray.

Soft washing relies on the cleaning solution. The cleaner is mixed to the label, applied at low pressure and left to work for the time the label gives. It is then rinsed off gently. The pressure is low, so it is far less likely to damage paint or force water into gaps.

The two methods often work together. We usually pre-treat mould on a driveway with a cleaner, then pressure wash it. On a painted wall, we only soft wash.

Use this as a general guide, and always check the surface first:

For more detail on concrete and pavers, see our page on driveway cleaning. If you want to clean a small area yourself, our guide on how to clean a driveway walks through each step.

Too much pressure on the wrong surface can do real damage. It can strip paint, chip paver edges, wash sand out of paver joints and open up cracks in old concrete. It can also push water behind cladding and into window seals.

The jet is also a danger to people. WorkSafe Victoria's safety alert on high-pressure water jetting warns that a water jet can pierce the skin and inject contaminated material into the body, and that flying debris can cause eye injuries. Its alert is written for workplaces, but the same care applies at home.

Soft washing has its own risks. The cleaner can harm plants and lawns, and it can mark some surfaces if it's mixed too strong or left on too long. That's why the label matters.

Soft washing depends on the right product used the right way. The Better Health Channel's advice on chemicals in the home says chemicals "may create a poisonous gas or liquid when mixed". It also says to keep acids away from alkaline products, read the label first, wear the recommended gloves, goggles and mask, and work in a well-ventilated space.

For work products, Safe Work Australia explains that safety data sheets hold important safety information about hazardous chemicals. If you're unsure how to use or store a product, the safety data sheet is the place to check.

Our team never mixes products, and we never use an acid product on a job where we've used a bleach-based cleaner. We dilute each product to its label and keep it on the surface only for the time the label gives.

Before any soft wash, water the nearby garden beds and cover delicate plants. Keep pets and children inside until the area is rinsed and dry.

The wash water matters too. In Canberra, the ACT Government's H2OK program states that there is no treatment plant for the stormwater system, so anything that runs into a street drain flows on to creeks and lakes. Access Canberra's guidance for mobile carpet cleaners says it is an offence to let contaminated water enter the stormwater system. Penalties range from on-the-spot fines to court fines of up to $50,000. The same guidance says wastewater should go to the sewer, for example through an outside gully trap, or to the client's garden if the client agrees.

That guidance is written for carpet cleaners, but the point applies to any outdoor cleaning. Sweep up leaves and dirt first, use only the product you need, and plan where the water will go before you start.

The ACT has permanent water conservation measures that set how outdoor surfaces can be cleaned. Paved areas can be cleaned at any time with a bucket and mop or a high-pressure, low-volume cleaner. Building exteriors can only be cleaned with a bucket and mop or brush, a squeegee, or a high-pressure, low-volume cleaner.

A running garden hose isn't one of the listed methods for walls.

A small concrete path is often a fine weekend job with a hired or home pressure washer. Soft washing is harder to do well at home, because it depends on choosing the right product, the right strength and the right dwell time.

A professional clean is usually the better choice when:

• the walls are painted, rendered or two storeys high
• there's heavy mould or black staining
• the area is large, or the surface is pavers or old concrete
• you'd need to work from a ladder

We never use a high-pressure lance from a ladder. A strong jet can push you off balance, and WorkSafe Victoria warns how serious jet injuries can be.

Aussie Duo is a family-owned cleaning business that has served Canberra since 2013. We check the surface, then choose pressure washing, soft washing or both. Our pressure cleaning is $4.40 per square metre including GST, with a $187 minimum job. See our pressure cleaning prices for worked examples. If you've got black spots on your paths, read our guide to removing mould from pavers.

Request a free quote or call 02 5501 3316. We usually reply within 30 minutes during business hours, Monday to Saturday, 7am–7pm.