How Often Should You Pressure Wash Your House (And When to Do It in Chicagoland)

Why Chicago winters make this more urgent than you think

A Chicago driveway looks fine. Until you see the neighbour's. Then it doesn't.

Chicagoland isn't Phoenix. Six months of freeze-thaw cycles push road salt and brine up against your siding, into concrete pores, and along the base of your fences. Humidity runs high enough in spring that algae and mold take hold fast, especially on north-facing walls that don't get direct sun for most of the year.

The grime that builds up over a Chicago winter isn't just cosmetic. It's also not the kind of thing you fix with a garden hose and some determination. We know because people try. Road salt is corrosive. Mold spores eat into wood surfaces if you let them sit through a second season. Algae on concrete gradually breaks down the surface, accelerating spalling. A house that looks reasonable in October can look noticeably worse by April.

We wash houses across Naperville, Arlington Heights, Schaumburg, Wheaton, and the rest of the north and northwest suburbs every spring. The difference in condition between a house washed annually and one that skips two years is visible from the street.

How often to pressure wash each surface

Different surfaces need different schedules. Concrete driveways take a beating from cars and salt. Siding is more protected but still picks up mold and exhaust residue. Here's what actually works (and yes, we're about to spend a whole table on your driveway schedule. You're welcome):

One thing that matters more than the calendar: shade. A north-facing wall in a wooded lot in Lisle can develop mold in eight months (the kind that looks almost decorative until you realise it's eating the surface). The same wall on a south-facing house in Bolingbrook might go fourteen months without an issue. If you're unsure, the warning signs in the next section are more reliable than any schedule.

The best time of year to pressure wash your house in Chicagoland

April through early May is the right window for a spring wash. Temperatures are consistently above 40°F, the last hard freeze has passed, and you're clearing six months of winter buildup before mold season starts. Washing in March risks a freeze afterward. Water in concrete pores can expand and cause spalling. March in Chicagoland is not your friend in this department.

September through mid-October is the second-best window. You're removing summer pollen and grime before winter. Good time to clean a deck before you cover it, or clear a driveway before road salt season starts again. The downside: mold has all winter to re-establish, so spring is the more effective primary wash.

What to avoid: washing in summer heat isn't dangerous, but it's less effective. Cleaning solution dries faster on hot surfaces before it can penetrate mold and algae. We still do summer washes, but adjust timing. Early morning when possible.

Don't wash when temps are below 40°F. Water left in surface pores can freeze overnight and crack concrete or cause spalling in brick. We mention this every spring and someone still calls us in February.

Signs your house needs washing now, regardless of schedule

Don't wait for the calendar if you see any of these:

• Black or green streaks running down siding. That's mold and algae moving with rainwater.
• Your driveway looks a shade darker than it used to, even on a dry day
• A deck or walkway that's slippery when wet. Algae film, not moisture alone.
• White chalky residue near the roofline or above windows. That's efflorescence, salt drawing out of brick.
• A clear clean/dirty line where an awning or overhang blocked rain, leaving the exposed area visibly grimier
• Your neighbors' houses look noticeably cleaner than yours after a spring wash

Any one of those means the buildup is already working against your surfaces. It's not just aesthetics at that point. It's about stopping ongoing damage. Also: your neighbours have definitely noticed.

Soft washing vs. pressure washing: which one does your house actually need

Most homeowners use “pressure washing” to describe any exterior cleaning. The method matters more than the name, and using the wrong one on the wrong surface causes damage that costs more to fix than the cleaning would have.

Here's a direct opinion: most residential pressure washing companies in Chicagoland use high pressure on vinyl siding because it's faster. It's the wrong method. High pressure (2,000 to 4,000 PSI) on vinyl can force water behind panels, crack older material, and void manufacturer warranties. The shortcuts show up two years later when siding starts warping, or mold comes back in eight weeks because the roots were never killed. Just the surface was blasted (which feels productive right up until it isn't). The Vinyl Siding Institute recommends soft washing specifically for this reason.

When we quote a house wash in Chicagoland, we're almost always soft washing the siding and pressure washing the driveway in the same visit. They're different processes with different equipment. Not just a pressure adjustment on the same wand.

What happens if you skip a year (or two)

A driveway that hasn't been washed in three years doesn't just look dirty. It looks like it's auditioning for a nature documentary.

You won't see immediate damage. That's what makes it easy to defer. But skipping two or three years has compounding effects:

• Mold and mildew penetrate wood grain. At that point you're looking at sanding or replacement, not just cleaning.
• Road salt left on concrete for multiple seasons contributes to pitting and surface breakdown
• Algae under deck paint lifts it from underneath, so you end up refinishing earlier than you would have.
• Paint on wood siding fades 30 to 40% faster when coated in grime that traps UV instead of reflecting it.

The job also takes longer. A house washed annually takes 3 to 4 hours. One that's gone three or four years takes 5 to 6 hours, sometimes more, and still shows residual staining in some areas that a single pass won't fully lift.

Skipping one year saves $200 to $375. Skipping two or three means paying for a longer job, dealing with mold that's penetrated surfaces, and potentially repainting sooner. The math on deferred maintenance is bad. An annual wash is the cheapest exterior maintenance a homeowner does, and the University of Illinois Extension backs that up.

Sam and Michael did a free wash for a neighbor in Elk Grove Village who had just gotten heart surgery. No charge, no ask. People in the neighborhood noticed. Jobs followed. That's still how most of their work comes in. We show up, we do the job, and we don't take bad shifts. That's the whole business model.

When not to hire a pressure washing company

A few situations where you should wait, or where pressure washing won't help. And yes, we're aware this is the part of the article where we talk ourselves out of jobs:

• Freshly painted within 60 to 90 days

  New paint needs time to cure. High pressure before that can lift edges and cause premature peeling, especially on wood surfaces.

• Cracked or damaged siding

  Pressure washing won't fix cracks. It'll force water into them and behind the panels. Get the damage repaired first, then wash.

• Older brick with failing mortar

  If you can see mortar crumbling between bricks, even low-pressure washing can accelerate the damage. Tuckpointing comes first. The EPA also notes that cleaning runoff from deteriorating surfaces can introduce contaminants into storm drains. Another reason to address structural issues before washing.

• Roofs with lifted or missing shingles

  We don't wash roofs, and you should be cautious of companies that do without a full inspection first. A damaged roof plus water pressure is a leak waiting to happen.

If something on your house isn't ready to be washed, we'll say so before we start. We'd rather lose the job.

Frequently asked questions