How to Clean a Patio Without a Pressure Washer

Why Clean a Patio Without a Pressure Washer?

Pressure washers have become the default answer to a dirty patio, but they come with a surprising number of downsides that most people only discover after buying one.

Cost. A decent pressure washer costs between £150 and £400. Hiring one for a day runs £30 to £60. For something you might use once or twice a year, that is a lot of money sitting in the shed.

Surface damage. High-pressure water erodes soft stone, blasts out pointing between slabs, and can permanently roughen concrete. Indian sandstone is particularly vulnerable. The irony is that the roughened surface then holds more moisture and grows more moss than before. Our guide on whether pressure washing actually removes moss covers this in detail.

Noise. Pressure washers are loud. Use one on a Sunday morning and you will hear about it from the neighbours. In terraced housing or semi-detached properties, the noise carries through walls.

Water waste. A typical pressure washer uses 400 to 600 litres of water per hour. With hosepipe bans becoming more common during UK summers, that is increasingly hard to justify.

You simply don’t own one. This is the most common reason of all. Not everyone has storage space, the budget, or the inclination to buy specialist equipment for a job that happens once a year.

The good news is that several methods work just as well, and some work better, than a pressure washer. Here is an honest look at each one.

Method 1: Soapy Water and a Stiff Brush

The classic approach. Fill a bucket with warm water, add a generous squirt of washing up liquid, and scrub the patio with a stiff yard brush.

How to do it

Sweep the patio to remove loose debris first. Mix warm water with washing up liquid in a bucket. Pour it over a section of paving and scrub vigorously with a stiff-bristled outdoor brush. Work in sections, rinsing each area with clean water before moving on. Repeat on stubborn patches.

Honest assessment

Pros: Costs almost nothing. No chemicals. No equipment to buy. Safe on all patio surfaces including natural stone.

Cons: Physically demanding, especially on larger patios. Only removes surface dirt and light algae. Does not kill moss, mould, or algae at root level. Regrowth happens within weeks. You will be doing this again next month.

Best for: Light surface dirt on small patios, or as a maintenance clean between proper treatments.

Method 2: Vinegar Solution

White vinegar is mildly acidic and can kill light moss and algae on contact. It is a popular recommendation in online cleaning guides.

How to do it

Mix equal parts white vinegar and water in a spray bottle or watering can. Apply generously to the affected areas. Leave for 15 to 30 minutes, then scrub with a stiff brush and rinse with clean water. For heavier growth, use undiluted vinegar and leave for an hour.

Honest assessment

Pros: Cheap and widely available. Kills light algae and thin moss on contact. No harsh chemical residues.

Cons: Ineffective against heavy or established moss growth. The acidity can etch and discolour natural stone, including limestone, marble, and Indian sandstone. No residual protection, so regrowth returns quickly. The smell is unpleasant during application. Our detailed guide on whether vinegar kills moss covers the limitations in full.

Best for: Light algae on concrete or block paving only. Avoid on natural stone.

Method 3: Baking Soda

Baking soda (sodium bicarbonate) raises the pH of the surface, creating conditions that moss and algae struggle to grow in.

How to do it

Sprinkle baking soda generously over damp moss or algae. Leave for 24 hours. Sweep or brush away the dead growth. Repeat as needed for stubborn areas. You can also dissolve three tablespoons in a litre of warm water and spray it on.

Honest assessment

Pros: Very gentle on all surfaces, including natural stone. Non-toxic to plants, pets, and wildlife. Cheap and available in any supermarket.

Cons: Very slow to work. Heavy moss needs multiple applications over several weeks. Washes away in rain, so you need a dry spell. Does not penetrate deep enough to kill established root systems. Our baking soda for moss guide explains why it struggles with anything beyond light surface growth.

Best for: Very light moss on delicate surfaces where you want the gentlest possible approach and are not in a hurry.

Method 4: Bleach

Household bleach (sodium hypochlorite) kills moss, algae, and mould on contact. It is effective, but it comes with significant drawbacks.

How to do it

Dilute one part bleach with five parts water. Apply to the affected area using a watering can. Leave for 20 to 30 minutes. Scrub with a stiff brush and rinse thoroughly with plenty of clean water. Wear gloves and eye protection. Keep pets and children away until fully rinsed.

Honest assessment

Pros: Kills moss, algae, and mould quickly. Cheap and readily available.

Cons: Can permanently discolour lighter paving stones. Kills or damages any plants it touches, including lawn edges and border plants. Harmful to soil organisms and can contaminate waterways through runoff. Provides no lasting protection against regrowth. The fumes are unpleasant and can irritate airways. Our bleach and moss guide covers the environmental and surface damage risks in detail.

Best for: Small areas of dark-coloured concrete where staining is not a concern and there are no nearby plants. Not recommended as a regular cleaning method.

Method 5: Commercial Spray-and-Leave Treatment

Spray-and-leave biocide treatments are specifically designed to clean patios without any pressure washing or scrubbing. You spray the product on, leave it to work over one to three weeks, and the dead growth either washes away in the rain or brushes off easily.

How to do it

Clear loose debris from the patio. Apply the treatment evenly across the surface using the product’s spray nozzle or a garden sprayer. Walk away. Over the following days and weeks, moss turns brown, algae fades, and mould breaks down. Brush away any remaining dead material once the treatment has finished working.

Honest assessment

Pros: By far the least physical effort of any method. Kills moss, algae, and mould at root level, not just the surface. Leaves a residual protective layer that prevents regrowth for months. Safe on all common patio surfaces including natural stone, concrete, block paving, and porcelain. No scrubbing, no kneeling, no aching back.

Cons: Costs money (typically £15 to £30 depending on patio size). Not instant. You need to wait one to three weeks for full results. Does not remove non-biological staining like oil, rust, or paint. If you want a comprehensive overview of the best products available, our best moss killer UK guide compares the leading options.

Best for: Anyone who wants lasting results with minimal effort. The go-to method for most patios, especially those with established moss, algae, or mould growth.

Method 6: Professional Cleaning Service

Hiring a professional patio cleaning company gets you expert-level results without lifting a finger.

What to expect

A professional service typically includes chemical pre-treatment, careful pressure washing with appropriate settings for your surface type, joint re-sanding for block paving, and sometimes a protective sealant. Expect to pay between £5 and £15 per square metre, with most average patios costing £150 to £400.

Honest assessment

Pros: Best possible results. They know which settings and chemicals suit each surface type. Includes everything from treatment to cleanup. Ideal for large, heavily soiled patios or expensive natural stone where DIY mistakes are costly.

Cons: The most expensive option by far. You need to book in advance and work around their schedule. Quality varies hugely between companies. Some use excessive pressure that causes damage. Always check reviews and ask what equipment and chemicals they use.

Best for: Large patios with severe growth, expensive natural stone, or anyone who values their time over the cost.

Comparison: Which Patio Cleaning Method Is Right for You?

For most people, the spray-and-leave approach hits the sweet spot between cost, effort, and results. It is the only method that kills biological growth at root level, requires almost no physical work, and keeps protecting the surface for months after application.

If your patio is simply dusty or has light surface grime with no biological growth, soapy water and a brush is perfectly adequate. Save the treatment for when you are dealing with actual moss, algae, or mould.

Step-by-Step: Cleaning Your Patio with a Spray-and-Leave Treatment

If you have decided the spray-and-leave approach is right for your patio, here is exactly how to get the best results.

Step 1: Choose the right time

Apply the treatment during a dry spell when no rain is forecast for at least six hours. This gives the product time to absorb into the surface and start working before it gets diluted. Spring and autumn are the ideal seasons, as moss and algae are actively growing and temperatures are moderate. Our timing guide explains why these windows matter.

Step 2: Clear the surface

Move furniture, plant pots, and anything else off the patio. Sweep thoroughly with a stiff broom to remove loose leaves, dirt, and debris. You want the treatment to contact the paving directly, not sit on top of debris.

Step 3: Apply the treatment

Spray the biocide treatment evenly across the entire patio surface. Pay extra attention to joints between slabs, shaded corners, and areas where moss or algae is thickest. Most products cover 40 to 60 square metres per litre, so check the coverage rate before you start.

Step 4: Walk away and wait

This is the best part. Once applied, leave the treatment to work. You will start seeing results within a few days. Green algae tends to die first, fading within three to five days. Moss takes one to two weeks to turn brown and die back. Thick lichen and embedded black mould can take up to three weeks for full clearance.

Step 5: Brush away dead growth

Once the growth is dead, use a stiff outdoor brush to sweep it away. It should come off easily without heavy scrubbing. For stubborn areas, a second application usually finishes the job. Rinse with a garden hose if needed.

Step 6: Prevent regrowth

The treatment leaves a residual protective layer on the surface that continues working for months. For best results, reapply twice a year in spring and autumn. Between applications, a quick weekly sweep stops organic matter building up and feeding new growth. Our prevention guide covers year-round maintenance in detail.

What to Expect: Realistic Timeline and Results

Managing expectations is important. A spray-and-leave treatment is not instant like a pressure washer. Here is what actually happens and when.

Day 1 to 3: The treatment absorbs into the surface and starts working on the biological growth. You may not see much change yet.

Day 3 to 7: Green algae begins to fade and discolour. Thin moss starts turning brown at the tips. The patio may look worse briefly as dying growth changes colour.

Week 1 to 2: Most algae is dead. Moss has turned brown and is starting to dry out. You can begin brushing away dead material from areas that have cleared.

Week 2 to 3: Thick moss and stubborn lichen finish dying off. The patio is ready for a final brush down. Heavy growth areas may benefit from a second application.

Month 1 to 6: The residual protective layer continues working, preventing new spores from establishing. Your patio stays cleaner for longer than any scrubbing method could achieve.

The speed of results depends on the severity of the growth, the type of surface, and the weather conditions after application. Warmer weather and some moisture actually help the treatment work faster, as the biological growth is more metabolically active.

For anyone dealing with moss on their patio specifically, our dedicated guide covers the full treatment approach in greater detail. And if your patio problem is part of a wider issue across paths, walls, and driveways, the complete moss, mould, and algae hub is the best place to start.

Frequently Asked Questions

Can I clean my patio with just soapy water?

Yes, warm soapy water and a stiff brush will remove surface dirt and light algae. However, it does not kill moss or algae at root level, so regrowth typically happens within a few weeks. For a lasting clean, combine scrubbing with a biocide treatment that prevents regrowth.

Will vinegar damage my patio?

Vinegar is mildly acidic and generally safe on concrete and block paving. However, it can etch and discolour natural stone like Indian sandstone, limestone, and marble. Always test on an inconspicuous area first. Vinegar is also ineffective against heavy moss or algae growth.

How long does a spray-and-leave patio cleaner take to work?

Most spray-and-leave treatments show visible results within a few days, with full clearance taking one to three weeks depending on the severity of growth. Green algae dies fastest. Thick moss and black lichen take longer. The treatment continues working on the surface for months after application.

Is it safe to use bleach on patio slabs?

Diluted bleach kills moss and algae on contact but can discolour paving, damage nearby plants, harm soil organisms, and contaminate waterways. It also provides no lasting prevention against regrowth. A dedicated patio treatment is safer for surfaces and the environment.

What is the best homemade patio cleaner?

The most effective homemade option is warm water with a few squirts of washing up liquid, applied with a stiff yard brush. It costs almost nothing and removes surface grime effectively. However, it does not kill biological growth like moss or algae, so it works best as a quick clean rather than a lasting solution.

Can I clean Indian sandstone without a pressure washer?

Yes, and you probably should. Pressure washing can damage Indian sandstone by eroding the surface and forcing water into the stone. A spray-and-leave biocide treatment is the safest method for natural stone, as it kills growth without physical abrasion. Avoid acidic cleaners like vinegar on sandstone.

How often should I clean my patio without a pressure washer?

For general maintenance, sweep your patio weekly and scrub with soapy water monthly during spring and summer. Apply a preventative biocide treatment once or twice a year, ideally in spring and autumn, to stop moss and algae establishing. This routine keeps most patios clean year-round without ever needing a pressure washer.