Well Water in Madera County: What to Test and Why

Groundwater in Madera County contains radon, trichloropropane, manganese, arsenic, chloride, fluoride, iron, lead, nitrate, uranium, sulfate, and other contaminants. Many of these exceed EPA health standards, which means well owners should test their water and consider treatment.

These contaminants come from multiple sources in the county's geology and human activity. Arsenic, uranium, and some metals occur naturally in the rock and sediment of the Central Valley aquifer system. Nitrate, chloride, and chemicals like trichloropropane enter groundwater from agricultural and industrial use on the land above. Radon seeps from the rock itself as it naturally decays underground.

Groundwater in this county is moderately hard, driven by dissolved calcium and magnesium from the aquifer materials. The moderate sodium and sulfate levels reflect minerals that dissolve slowly as water moves through the underground gravel and clay layers. These mineral characteristics are found across many wells throughout the county.

Wells in Madera County commonly contain arsenic, lead, uranium, radon, fluoride, nitrate, chloride, sulfate, PFOA, PFOS, PFHXS, and trichloropropane at levels that exceed EPA health standards. Arsenic and uranium can damage your kidneys and increase cancer risk with long-term exposure. Lead harms children's brain development and causes learning problems. Radon is a radioactive gas that increases lung cancer risk. Nitrate is especially dangerous for infants and can cause a serious blood condition. PFOA, PFOS, and related chemicals affect the liver and immune system. Fluoride, chloride, and sulfate at elevated levels also pose health concerns.

Wells in this county have moderately hard water, which causes white scale buildup on faucets, in pipes, and on shower doors. Hard water can shorten the lifespan of water heaters, dishwashers, and washing machines. You may notice spots on dishes, reduced water pressure from mineral deposits, and dry skin or stiff hair after showering.

Testing is the only way to know what is actually in your well, since every well is different and yours could have higher or lower levels than the county average. We recommend a comprehensive water quality panel that checks for metals, minerals, and contaminants, which typically costs $200 to $400. Treatment options like reverse osmosis filters, ion exchange softeners, or activated carbon can address different contaminants depending on what testing reveals.