How often should you clean vinyl siding?
Updated July 2026
Vinyl siding needs a wash once a year, and the method matters as much as the timing: use a soft wash (a garden hose, a soft-bristle brush, and a mild cleaner) rather than a high-pressure blast. The goal is to lift the mildew, algae, pollen, and road film that settle on the surface. Shaded, damp walls, usually the north side, grow green and black faster, so give those a second pass mid-season. Left alone, that growth stains the panels and traps moisture against the wall.
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| Sunny, well-drained walls | Once a year | Sun and airflow keep growth down between washes |
| North side or shaded walls | Twice a year | Damp shade is where algae and mildew take hold |
| Under trees or beside a lawn | Twice a year | Sap, pollen, and mud splash load the lower panels |
| Humid or Gulf climate | Twice a year | Warm, wet air grows mildew almost year-round |
| After spring pollen season | Spot wash | A yellow film left on the panels holds moisture and stains |
| Chalky, faded older siding | Gentle wash only | Aggressive scrubbing streaks oxidized vinyl |
The cost of skipping it
What skipping it costs: the damage here is slow and mostly cosmetic, but it is real. Algae and mildew stain the panels a dull green-black that gets harder to remove the longer it sits, and moisture trapped under the growth can reach the sheathing behind the siding on shaded walls. A yearly wash is cheap: a jug of siding cleaner is $10 to $20, and a pro soft-wash of a whole house runs $250 to $500. Vinyl siding is built to last 20 to 40 years; neglect the wash and you are looking at replacing stained panels or repainting siding that never should have needed it.
How to do it (A few hours · DIY, hose and a soft brush on a pole)
- Work on a cloudy day or in the shade so the cleaner does not dry before you rinse.
- Wet nearby plants first and cover anything delicate, then rinse them again after.
- Mix a mild siding cleaner (or a vinegar or oxygen-bleach solution) per the label.
- Wash from the bottom up with a soft brush on a pole to avoid streaks, scrubbing stained spots gently.
- Rinse top to bottom with a garden hose, keeping the water aimed downward so it does not drive behind the laps.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing siding washing schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
Can I pressure wash vinyl siding?
You can, but carefully, and many pros avoid it. High pressure and a narrow tip can crack panels, gouge the surface, and force water up behind the laps into the wall, where it feeds mold. If you do use a pressure washer, keep it under about 1,500 psi, fit a wide 40-degree tip, hold it a couple of feet back, and always spray downward and level, never up under the laps. A soft wash with a brush and a garden hose is safer and cleans just as well.
What is the best cleaner for mildew and green algae on siding?
A solution of oxygen bleach (sodium percarbonate) or plain white vinegar and water handles most mildew and algae and is gentle on plants. Dedicated siding cleaners work well too. Avoid chlorine bleach where you can, since it kills the growth but also harms shrubs and grass and can lighten the vinyl if left to sit. Whatever you use, wet the landscaping first, keep the cleaner off it as much as possible, and rinse everything thoroughly when you finish.
Why does the north side of my house stay green?
Because it gets the least sun and stays damp the longest. Algae and mildew need moisture, and a shaded north or northeast wall holds it long after the sunny sides have dried. That is why the shaded face often needs washing twice a year while the rest of the house is fine once. Trimming back shrubs and tree limbs to let in more light and airflow slows the regrowth between washes.
Does dirty siding actually damage the vinyl?
The dirt itself is cosmetic, but two things do real harm. Mildew and algae, left for years, stain the surface deeply enough that you may not be able to fully clean it. And on shaded walls, growth holds moisture against the panels and the sheathing behind them, which over time can reach the wall structure. A yearly wash keeps both from ever starting. While you are at it, check the panels for cracks; see the vinyl siding maintenance checklist.