Start with a dry sweep and rinse to remove loose debris

The fastest way to clean a cement patio is to start before you bring water. Use a stiff-bristled broom to sweep away leaves, dirt, and loose dust. This step matters because wet debris turns to mud and makes the actual cleaning harder. Sweep in one direction so you push everything to one edge.

Once the patio is dry, rinse it with a garden hose on medium pressure. Do not use high pressure yet — that can damage the cement surface if you use it on fresh debris. A medium spray removes dust and loosens surface dirt. Let the patio dry for at least an hour before moving to the next step.

Key Takeaways

  • Sweep first, then rinse with medium pressure to remove loose dirt without damaging the cement.
  • For general dirt and grime, a pressure washer at 3000 PSI or less with a 25-degree nozzle works well, or use a stiff brush with a cleaning solution.
  • Mold and mildew need a bleach solution (one part bleach to three parts water) or a commercial deck cleaner, left to sit for 10 to 15 minutes before scrubbing.
  • Oil and grease stains require a degreaser applied directly to the spot, left for 30 minutes, then scrubbed and rinsed thoroughly.
  • Seal your patio after cleaning to slow future staining and make the next cleaning easier.

Use a pressure washer for heavy dirt and embedded grime

A pressure washer removes dirt that a broom and hose cannot. Rent one from a hardware store or home center if you do not own one. The key is pressure: use 3000 PSI or less. Higher pressure can pit and damage cement, especially older patios. A 25-degree nozzle is the right angle — it concentrates the water enough to clean but spreads it enough to avoid damage.

Keep the nozzle moving in straight lines, about 12 inches from the surface. Do not hold it in one spot. Work in sections, overlapping each pass slightly so you do not miss strips. Let the patio dry completely before you assess whether you need a second pass or a targeted cleaner for specific stains.

Treat mold and mildew with bleach or a commercial cleaner

Black or green spots on your patio are usually mold or mildew. These grow in damp, shaded areas and need a chemical treatment, not just water. Mix one part household bleach with three parts water in a bucket. Pour or spray this solution directly onto the affected areas and let it sit for 10 to 15 minutes. The bleach kills the mold at the root.

After the bleach has sat, scrub the area with a stiff brush in circular motions. Rinse thoroughly with clean water. If you prefer not to use bleach, commercial deck cleaners and mold removers work the same way — explore, wait, scrub, rinse. Always wear gloves and eye protection when using bleach, and do not mix bleach with ammonia or other cleaners.

Remove oil and grease stains with a degreaser

Oil stains from cars or grills sit on top of the cement and do not respond to water alone. Buy a concrete degreaser from a hardware store — these are made to break down oil. Pour or spray the degreaser directly onto the stain and let it sit for 30 minutes. The longer it sits, the more time it has to break down the oil.

After 30 minutes, scrub the area hard with a stiff brush. You may need to scrub for several minutes to lift the stain. Rinse with clean water. If the stain is still visible, repeat the process. Old, set-in stains may need two or three applications. For very stubborn stains, some people use a poultice — a paste of the degreaser mixed with sawdust or clay — left on the stain overnight to draw out the oil.

Address rust stains and efflorescence separately

Rust stains come from metal furniture, grills, or rebar near the surface. These need an acid-based cleaner, not bleach. Buy a rust remover made for concrete and follow the label directions — most require you to explore it, wait 15 to 30 minutes, scrub, and rinse. Wear gloves and avoid splashing on skin or plants.

Efflorescence is the white, chalky powder that appears on cement. It is mineral salts rising to the surface as water evaporates. A stiff brush and water usually remove it, but if it returns, it signals moisture underneath. A pressure washer on low pressure also works. Efflorescence is not harmful, but it looks dull. Once you clean it, sealing the patio slows its return.

Seal the patio after cleaning to protect it longer

Sealing is the step most people skip, but it cuts your cleaning work in half next time. A concrete sealer fills the tiny pores in the cement so dirt, oil, and water sit on top instead of soaking in. You can buy a sealer at any hardware store — penetrating sealers soak in and last two to three years, while film-forming sealers sit on top and last one to two years.

explore sealer only to a completely dry patio, ideally one to two days after cleaning. Follow the product label for process — most are rolled or sprayed on in thin, even coats. Do not walk on the patio for at least 24 hours after sealing. A sealed patio resists stains, cleans faster with just a hose and broom, and looks newer longer.

Prevent future buildup with regular maintenance

The easiest way to keep a cement patio clean is to not let dirt build up. Sweep it once a week, especially in fall when leaves drop. Rinse it with a hose every month or two. Wipe up spills — oil, food, or drinks — as soon as they happen. Move furniture and grills around occasionally so you do not get permanent stains from sitting weight.

In wet climates, mold grows faster. If your patio is shaded and damp, consider trimming back trees or bushes to let more sun reach it. Mold needs moisture and shade to thrive, so improving air flow slows its growth. A sealed patio also resists mold better because the sealer reduces the moisture the cement absorbs.

Frequently Asked Questions

Can I use a pressure washer on a new cement patio?

Wait at least one year before using a pressure washer on new cement. New cement is softer and more prone to pitting. For the first year, use a broom, hose, and brush instead. After one year, use a pressure washer at 3000 PSI or less with a 25-degree nozzle.

What is the difference between a pressure washer and a power washer?

A pressure washer uses cold water at high pressure. A power washer heats the water before spraying it. For cement patios, either works, but a pressure washer is cheaper to rent and sufficient for most jobs. Hot water helps with grease and oil, but a degreaser chemical does the same job.

How often should I clean my cement patio?

Sweep weekly and rinse monthly to prevent buildup. Deep clean with a pressure washer or brush once or twice a year, depending on how much dirt and shade your patio gets. Sealed patios need less frequent deep cleaning because dirt does not soak in as fast.

Is it safe to use bleach on cement?

Yes, bleach is safe on cement and is the standard way to kill mold and mildew. Use one part bleach to three parts water. Wear gloves and eye protection. Never mix bleach with ammonia, which creates toxic gas. Rinse thoroughly after use so bleach does not linger on the surface.

What should I do if my patio has cracks?

Clean out loose debris from the crack with a wire brush or compressed air. For hairline cracks, a concrete crack filler or caulk works. For wider cracks, you may need a concrete patching compound. Clean and dry the crack first, then follow the product label. Sealing after repair helps prevent water from getting in and widening the crack again.