Stains in South Florida.

Yes, the iron staining is mostly due to the water treatment and handling process—not from natural groundwater.

Here’s what’s likely happening:

🔶 Why There's Iron in Reclaimed Water

Reclaimed (or reclaimed/“reuse”) water is treated municipal wastewater, not raw groundwater. Although groundwater in many parts of Florida is relatively low in iron, reclaimed water can still contain:

1. Residual Iron from Municipal Water Sources

• Some of the original water sources that feed into wastewater treatment plants may have iron, especially if they include well water or surface water with iron content.

2. Iron from the Collection and Treatment Process

• Wastewater picks up iron from corroded iron pipes, manholes, and infrastructure along the way.

• During treatment, iron might not be fully removed, especially if it’s not prioritized for removal (since it's not a health concern—just aesthetic).

3. Reactions with Chlorine or Other Oxidants

• Reclaimed water is often chlorinated before distribution, and chlorine oxidizes any dissolved (ferrous) iron into insoluble (ferric) iron, which then stains surfaces orange when sprayed and dries.

🔧 Why Stains Appear on Surfaces

When irrigation systems spray this iron-rich water onto sidewalks, stucco, fences, etc.:

• The iron oxidizes (like rust) when exposed to air.

• It binds to porous surfaces, especially concrete, wood, and stucco, leaving persistent rust-colored stains.

✅ Can It Be Prevented?

• Filtration or sequestration of iron before distribution could help—but many municipal reclaimed water systems don’t include this because it’s costly.

• Homeowners can use post-filtration, polyphosphate injection, or iron-neutralizing systems—but these are not common.

• Some irrigation systems use stain-free heads or directional nozzles to limit overspray on buildings and pavement.

🔁 Summary

Even though South Florida groundwater is generally low in natural iron, reclaimed irrigation water stains are caused by residual or introduced iron from the wastewater treatment and distribution process. It's more about how the water is handled than where it originally came from.