Although durable and beautiful, stucco is also porous and accumulates dirt over time. Stucco can also develop mildew or algae on its surface, especially on northern-facing or shady walls, behind shrubbery, and in humid climates. Stucco siding should be cleaned at least once a year to prevent the accumulation of dirt, algae, mold, mildew, efflorescence, air pollution, pollen, and dust build-up. If you plan to paint stucco, always repair and clean it first – never paint over dirt, stains, mildew, or algae.

Properly maintaining a stucco exterior helps ensure its long lifespan and attractive appearance. It’s important to know the dos and don’ts so you can clean and protect your stucco the right way. Follow these seven simple steps to clean your stucco like a pro:

Cleaning Stucco

1. Inspect the stucco surface for cracks, gaps, chips, or holes.

  • Washing stucco that is cracked, has gaps, chips, or holes, can allow water to enter the damaged areas.
  • Water that enters unrepaired stucco encourages mold, mildew build-up, and potential long-term problems.
  • Don’t proceed with cleaning until the damage is repaired.

2. Repair any damage before cleaning.

  • You can repair minor damage on your own. Choose an exterior acrylic caulk in a color closest to the color of your stucco. Fill hairline cracks, holes, or chipped areas. While the caulk is still wet, press sand or a gritty substance into it so it resembles the texture of the surrounding stucco surface.
  • Be sure the repairs have completely dried before cleaning the stucco. Usually, give caulk at least a week to dry completely.
  • If the damage is extensive, or you feel you can’t tackle the repairs by yourself, trust CLAD Siding to connect you with a top-rated licensed and insured stucco contractor near you. Getting a free quote is fast and easy!

3. Pre-wet the stucco surface.

  • Spray the stucco surface to clean off any loose dirt and dust. Pre-wetting allows the cleaning products to work more efficiently.
  • If using an attachment nozzle on the hose, select a gentle setting, not “jet”.
  • Start at the bottom of the surface and work your way to the top.
  • Pre-wet long enough to see dirt dissipate and fall off.

4. Choose a cleaning method.

  • You can use a pressure washer. If you power wash, follow the manufacturer’s directions for appropriate nozzles and pressure for stucco.
    • It’s easy to damage stucco by using too much pressure or the wrong nozzles. See below (Apply the cleaning product) for suggested nozzles and pressure.
    • Also, if pressure washing, be sure to protect any plants close to the building. A power washer can rip plants to shreds in seconds.
  • Garden hose, bucket, and a soft-bristled brush.

5. Choose a cleaning product.

  • To simply remove dirt and dust, use liquid dish soap or TSP (trisodium phosphate) diluted with water.
  • To remove algae (usually green) or mildew (usually black), use a mix of equal parts soapy water and bleach.
    • When using bleach, be sure to wear rubber gloves, a mask, and goggles.
    • If you have children, warn them about the dangers of bleach.
  • If you prefer not to use bleach, you can use borax with soapy water. Mix ½ cup borax, 2 tablespoons liquid dish soap, and 2 gallons of warm water.
  • Alternatively, you can purchase a concentrated stucco cleaner at any home improvement store. Read the mixing instructions carefully.
  • For the strongest cleaner, you can mix bleach with the commercial stucco cleaner to get stains out. Often these commercial cleaners are activated by bleach.
  • If crystalline salt deposits are a problem (efflorescence), the powdery deposit can be neutralized by spraying with undiluted white vinegar.
  • Avoid using harsh cleaning products that can damage the stucco ingredients (portland cement, lime, or pigment).

6. Apply the cleaning product.

  • If using a pressure washer, place the cleaning product in the detergent tank according to manufacturer and product specifications. Use a 65-degree nozzle tip and a pressure level of 1,500 psi or lower. Maintaining a minimum of 20 inches between the nozzle and the stucco surface, start at the top of the wall and work your way down. Make sure the pressure washer nozzle is pointing at a downward angle, not directly at the stucco surface.
  • If using a bucket, wet a soft-bristle brush in the cleaning product and start gently scrubbing at the top of the stucco wall, working down. Scrub sufficiently to see noticeable cleaning without damaging the stucco surface.
  • Allow the cleaning solution to sit for 5 to 10 minutes but don’t let it dry, otherwise, it will be difficult to rinse off. You can lightly spray it every few minutes to keep it moist.
  • Stubborn stains. Hard to remove stains may need extra scrubbing. Continue to scrub gently and let the cleaning product do the majority of the work.

7. Rinse.

  • Rinse the surface starting at the top of the stucco and working your way to the bottom.
  • If using a hose with an attachment nozzle, use only a gentle setting, not “jet”.
  • If using a pressure washer, change to a 40-degree nozzle for rinsing and maintain a 20-inch distance from the stucco surface.

If cleaning your stucco seems like too big a job, you’re uncomfortable climbing a ladder, or you simply don’t have time, hire a professional to do the repairs and cleaning for you. How do you find a reputable pro to do the job? First of all, you want to make sure you hire a licensed and insured contractor who has the expertise to repair, protect, and clean stucco. CLAD Siding is the fastest and easiest way to find a licensed and insured stucco expert near you.


Whether residential or commercial – installation, cleaning, or repairs – CLAD Siding will help you find the best licensed and insured stucco siding contractors in your area. Find a pro today and get your stucco cleaned in a flash. Get a free quote now!