Well Water in Colusa County: What to Test and Why

Groundwater in Colusa County contains several contaminants that well owners should be aware of, including arsenic, chloride, fluoride, iron, lead, manganese, nitrate, sulfate, and uranium. Many of these contaminants are present at levels high enough to exceed EPA health standards, which means they warrant attention and testing.

These contaminants come from a mix of natural and human sources in the local geology and land use. The county's rocks naturally contain minerals like iron and manganese that dissolve into groundwater. Agricultural activities, including fertilizer and pesticide use across the region's farmland, contribute nitrate and other chemicals that seep downward into water supplies. Some contaminants like arsenic and uranium occur naturally in the local rocks.

Groundwater in this county is very hard, driven mainly by elevated calcium and magnesium from the rocks below, and it also carries high sodium and moderate iron. The hard minerals and sodium concentrate here because water moving through the local rocks slowly dissolves these elements and carries them into the aquifer. These mineral characteristics are widespread across wells in the county.

Wells in Colusa County have been found with arsenic, chloride, fluoride, iron, lead, manganese, nitrate, sulfate, and uranium at levels above EPA health standards. Arsenic and uranium are known to increase cancer risk and cause organ damage over time. Lead harms children's brain development and affects adult kidney and heart function. Nitrate poses serious risks to infants and can cause breathing problems. Manganese at high levels damages the nervous system, especially in children.

County well water is extremely hard, which means mineral buildup will form scale inside pipes and appliances like water heaters and dishwashers, shortening their lifespan. The high sodium content and iron create staining on fixtures and laundry. You may notice a metallic or sulfur taste or odor in your water. These mineral issues require ongoing cleaning and maintenance.

We recommend testing your well water with a comprehensive panel since multiple contaminants exceed health standards in this county. Every well is different, and your water could have higher or lower levels than what is common here. Testing is the only way to know exactly what is in your well so you can treat it properly. A comprehensive metals and minerals panel costs between two hundred and four hundred dollars. Treatment options range from whole-house filtration systems to point-of-use filters, depending on what testing shows.