Oil spots, rust marks, and green algae are the three most common stains on Katy driveways and patios. Katy Elite Concrete Contractor shares safe cleaning steps that protect the surface and help you decide when a stain needs more than a scrub.
Start with the gentlest method
Sweep the surface first. Try warm water and a stiff brush before any strong product. Many light stains lift with soap, water, and a little patience.
Oil and grease
Soak up fresh oil with an absorbent such as cat litter or sawdust, then sweep it away. For old stains, apply a degreaser made for concrete, let it sit as directed, scrub, and rinse. Deep stains may need more than one round. Test any product on a small spot first.
Rust stains
Rust often comes from metal furniture, sprinklers, or well water. A cleaner made for rust can help. Keep metal off wet concrete and check sprinkler heads that spray onto the slab.
Green algae and mildew
Shade and moisture help algae grow, and Katy’s humid weather gives it plenty of both. Scrub with a mild cleaner, rinse well, and improve drainage and sunlight where you can. Trim shrubs that keep the slab damp.
A word on pressure washing
Pressure washers clean fast, but too much pressure can scar concrete and strip the surface. Use a wide fan tip, keep the wand moving, and stay a safe distance away. Stamped and colored finishes need extra care, so see our finish guide.
Protect the surface afterward
A clean, dry slab can be sealed to slow future stains. Read how in our sealing guide or ask about our repair options if the surface is worn.
Safe tools and products
Wear gloves and eye protection with any cleaner. Never mix cleaning products, since some combinations make harmful fumes. Read each label, and rinse plants and grass near the work area. Keep pets and kids away until the surface is dry.
Stubborn and old stains
Stains that have soaked in for years can be hard to lift. A poultice, which is a paste that draws stains out, can help with oil. Repeat applications may be needed. If the stain remains, a surface treatment or resurfacing may be a better route than endless scrubbing.
Prevent future stains
Place a drip tray or mat under a leaking car. Keep fertilizer and plant debris off the slab. Clean spills quickly. A sealer can make cleanup easier. Fix drainage problems so water does not sit on the surface and feed algae.
When the surface itself is damaged
If cleaning reveals flaking, pitting, or crumbling, the issue is the concrete, not just the stain. A repair or resurfacing plan may be needed. Take photos before and after cleaning so you can show your contractor what you see.
Cleaning questions
Is bleach safe on concrete? It can kill algae but can also harm plants and some finishes. Check the product label and rinse well.
Can I use vinegar? Mild acids can etch concrete. Test a small spot first and avoid it on sealed or colored surfaces.
How often should I clean? A seasonal wash keeps most slabs in good shape.
What if the stain returns? Look for the cause, such as a leak or poor drainage.
Cleaning toolkit
- Stiff brush and bucket
- Mild degreaser for concrete
- Absorbent for fresh spills
- Gloves and eye protection
- A hose with a gentle nozzle
Keep these handy so spills never sit long enough to stain.
When stains will not budge or the surface is crumbling, it may be time for resurfacing or repair. Send us a photo.
