Answer first: Boat Dock Repair Osage Beach soft washes docks across the lake. Aluminum wants roughly 500 psi with the wand 10 to 12 inches off the surface, not high pressure held close. Algae generally comes off with pressure alone; mold and mildew need a cleaner given time to work before rinsing. Because everything we rinse goes straight into the lake, the product has to be biodegradable, phosphate-free, and near neutral pH. The practical benefit beyond appearance is that a clean dock is one you can actually inspect.
Pressure is the part people get wrong
A pressure washer that is right for concrete is wrong for a dock. Aluminum is soft, and a concentrated jet held close will mark it, work water into seams and fastener penetrations, and leave streaking that becomes permanent. The technique that works is the opposite of intuition: lower pressure, more distance, more patience, and a cleaner doing the part that force cannot.
Around 500 psi with the wand kept back 10 to 12 inches is the working range for aluminum. Composite and wood decking each behave differently again. The general rule holds across all of them, which is that the surface should be cleaned rather than blasted, and the cost of getting this wrong is not a redo, it is a permanently marked dock.
What comes off with pressure, and what does not
| What is on the dock | What it needs | Notes |
|---|---|---|
| Green algae at and above the waterline | Soft wash pressure, usually sufficient alone | Returns every season. Normal, not a failure. |
| Mold and mildew, dark spotting | Cleaning solution with dwell time, then rinse | Pressure alone tends to smear rather than remove |
| General grime and traffic film on aluminum | Oxalic acid based cleaner, soft wash | Standard approach for aluminum surfaces |
| Rust streaking below fasteners | Cleaning reveals it; the fastener is the actual issue | Flag for repair, not more washing |
| Dock rash, scraped and gouged aluminum | Nothing. This is physical damage. | Repair conversation, not a cleaning one |
Runoff is not a preference here
On a driveway, cleaner choice is mostly about results. On a dock there is no buffer at all: no drain, no soil, no lawn. Whatever comes off the dock is in the lake within seconds, and this is a lake people swim in and pull drinking water near. That constraint decides the product list before anything else does.
What that means in practice is biodegradable, phosphate-free, close to neutral pH, and non-corrosive to the metal we are standing on. It also means we will decline to use some products owners have read about, and we would rather explain why than quietly use them.
The reason we like doing this before other work
A clean dock is an inspectable dock, and that is worth more than the appearance. Under a film of algae and grime you cannot see a hairline crack in a float, a fastener beginning to corrode, rust tracking out of a weld, or the early scuffing that says a boat is working against the dock edge every time the wind comes up.
More than once a cleaning visit has been how a genuine problem got found while it was still small. If we spot something, you get told and you get a photo of it, whether or not you want us to do anything about it. Growth also tends to be heaviest right at the waterline, which is exactly where float condition is judged, so the two jobs pair naturally.
Timing and cost
Spring is the obvious time, once the lake has come back up from its winter low and before the season starts. Autumn is the underrated one: going into winter clean means less organic material sitting against the surface for months, and it pairs with the rest of winter preparation while someone is already out there.
Cleaning is priced by dock size, surface type, growth, and access, and it is quoted in writing before work starts like everything else here. Ranges sit alongside the repair list in the cost guide. If the wash turns up damage rather than dirt, that is a separate quote and a separate decision, never something added to an invoice after the fact.