Water problems library
Orange and red stains
Rust-colored marks in sinks, tubs, toilets or on laundry.
Possible causes
- Dissolved iron that oxidizes on contact with air.
- Particulate iron from the well or aging pipes.
- Iron bacteria — usually with slimy or gel-like deposits.
What evidence helps
The stain's texture (powdery vs slimy), whether it's whole-home, and an iron test that distinguishes dissolved from particulate forms.
Honest next steps
Check the texture
Slimy deposits raise the bacteria question — an ordinary iron filter won't solve that.
Test for iron forms
Dissolved, particulate and bacterial iron need different equipment. The test costs far less than the wrong filter.
Match the treatment
Oxidizing filters, aeration or chlorination each fit specific confirmed conditions.
Color alone can't diagnose iron — and slime can mean bacteria. Test before treating.