We all know water is fundamental to our lives, and to all livings things. But do you ever stop and think about the water you have access to, and if it is actually clean?

It depends on your perspective, says John Luczaj, head of UW-Green Bay’s geosciences program.

“If you’re a fisheries person, you might think of surface water quality. If you live in a house where lead levels are elevated, you probably think of drinking water. I’m a geologist so I usually think of ground water quality,” Luczaj says.

No matter how you look at it, he says multiple factors influence water quality. Around the state soils vary — from sandy to clay. The depth of those soils differs, and so does the bedrock below. Luczaj says all of those variables affect how the ability to filter contaminants.

Another variable is how far down groundwater is and where it flows.

Then factor in how humans live and work on those landscapes, Luczaj says. Take nitrate. It’s a natural chemical, but too much of it (in the form of manure and fertilizer) can seep into well water, making it dangerous to drink. Nitrate is one of the pollutants that contaminate wells.