The short answer
Orange stains along the bottom of a stucco wall are usually irrigation rust: iron from sprinkler water that oxidized on the surface. Stucco is porous and usually painted, so it needs a careful approach: a rust remover suited to the finish, tested in a small spot first, applied without high pressure, and rinsed thoroughly.
How to tell it’s irrigation rust
- The staining starts at ground level and fades upward, about as high as the spray reaches.
- It’s heaviest near a sprinkler head and lighter between heads.
- It’s orange to reddish brown, not green or black (that’s algae or mildew).
- It comes back in the same spots after cleaning.
Why stucco needs extra care
Unlike vinyl, stucco is textured and porous, so the iron settles into the surface. Most stucco is also painted, and the paint can react to strong chemicals or be blasted off by high pressure. Older and patched stucco is more delicate still. That’s why the treatment has to be matched to the finish, and why testing a small, out-of-the-way area first matters.
What to avoid
- High-pressure washing. It can etch stucco, strip paint and force water behind the finish, and the orange often stays.
- Scrubbing with stiff brushes. It can rough up the texture and leave visible patches.
- Letting product dry on the wall. Work in the shade and rinse well.
- Forgetting the beds. Whatever you rinse off lands on the plants at the base of the wall, so protect them first.
Should you just paint over it?
Painting can hide the stain for a while, but if the sprinklers keep spraying iron-rich water on the wall, the orange comes back on the new paint. Removing the rust and then dealing with the water is usually cheaper than repainting the bottom of the house every year or two.
Stopping it from coming back
Redirecting heads away from the wall helps where it’s possible. On properties that irrigate from a private well, an irrigation rust prevention system treats the water so new staining doesn’t form. We’ll test your water for free to see if that’s worth it.
Getting it done
We remove irrigation rust from stucco homes, condo buildings and commercial walls across Tampa Bay. Find your area on our service areas page, or read about irrigation rust removal.