What Causes Orange Water from a Well?
What Causes Orange Water from a Well — Deep Dive Plumbing Maryland
Orange or rust-colored water from a well is almost always caused by iron — one of the most common water quality problems in Maryland. Here's what causes it, how to confirm it, and how to fix it permanently.
5 Causes of Orange Well Water
Dissolved Iron in Well Water
The most common cause in Maryland. Iron occurs naturally in the Aquia and Magothy aquifers that supply most Calvert and Anne Arundel County wells. Dissolved (ferrous) iron is invisible in the water as it comes out of the tap — but it oxidizes when exposed to air and turns orange. Even 0.3 mg/L of iron causes visible staining.
Iron Bacteria
Iron bacteria are microorganisms that feed on dissolved iron and deposit iron compounds as a byproduct. They produce the orange or rust-colored slime you see in toilet tanks and the orange staining that comes back quickly after cleaning. Iron bacteria are not a health hazard but are very difficult to eliminate without treating the well.
Corroding Pipes
Galvanized steel pipes corrode from the inside out. As the zinc coating wears away, the steel rusts and releases orange particles into the water. If your home has galvanized pipes (common in homes built before 1970), the orange water may be coming from your plumbing, not your well.
Disturbed Sediment
After a power outage, pump replacement, or nearby construction, sediment in the well or water lines can be disturbed and temporarily turn the water orange. This usually clears within a few hours of running the water.
Manganese
Manganese causes black or dark brown staining rather than orange, but it's often present alongside iron. Water with both iron and manganese may appear orange-brown or rust-colored.
The Damage Iron Does to Your Home
How to Fix Orange Well Water in Maryland
The fix depends on the type of iron and the concentration. A water test is the essential first step — it tells us the iron level, the type of iron (dissolved vs. particulate), whether iron bacteria are present, and what other contaminants need to be addressed.
For most Maryland homes, an air injection oxidizing (AIO) iron filter is the most effective solution. It oxidizes dissolved iron, then filters out the particles — removing iron, manganese, and hydrogen sulfide in a single system. No chemicals required.
If iron bacteria are present, the well must be shock-chlorinated first to kill the bacteria, then an iron filter is installed to prevent recurrence. Iron bacteria are persistent — they will recolonize the well if only the filter is installed without treating the well.