How we keep wash water out of the storm drains.

Every wash ends up somewhere.

A pressure wash sends water across concrete, down walls and through enclosures, and that water picks up whatever it cleans: dirt, grit, food residue and oil from parking stalls. Where it heads next matters to the property, the neighbors and the street. Thinking about it before a hose is connected is part of planning a good wash.

On a busy commercial property, the water and grime add up quickly. A full parking field or a long row of storefronts covers a lot of ground, which is why runoff gets planned the same way the washing order does.

The answer starts with the drains. Most commercial properties have storm drains in the lot, curb inlets along the street and grates in plazas, walkways and trash enclosures. Some sit in plain view in the middle of a drive aisle, and others hide under mats, planters or along the base of a curb.

Each one is a path off the property, and each one gets a plan before the first pass.

Keeping water around the work area.

Covering drains is one part of the plan. The crew also reads how the ground slopes, since water follows the low line across a lot or plaza. Washing is laid out so water moves away from entries and doors, and walls are washed from the top down and rinsed away from the building. Our guide to commercial stucco cleaning shows how that top-down order works on a wall.

Low spots where water pools are noted at the walkthrough, so nothing surprises anyone at night. Trash enclosures get the same care, with the inlets closest to the pad covered before any water goes down.

Garages and covered decks have their own drain layouts, so the crew looks at each one before setting the order of work, then works level by level.

What owners can do to help.

You know the property’s drains better than anyone. At the walkthrough, point out every storm drain and curb inlet near the areas being washed, along with drains that are easy to miss, such as a grate tucked under a planter or a slot drain at the foot of a ramp. Mention any spot that floods in a heavy rain, since wash water will head there too.

Between visits, regular sweeping and quick pickup of spills keep less material on the ground, so there is less for each wash to move. Lids kept closed on bins and grease containers do the same job at the enclosure.

Tell us, too, about anything that changes between the walkthrough and wash night: new planters, a freshly planted bed, a temporary fence or a tenant’s outdoor setup. Each one can change where water travels.