How where you live affects the contaminants in your water Your geography can have a big impact on your water quality. So what is the water quality likely to be near you? Ground water is filtered by bodies of rocks underneath you known as aquifers, so the consistency of those aquifers can make a big difference to the water quality that you have available. How water moves through aquifers Many different types of sediments and rocks can form aquifers, including gravel, sandstone, conglomerates, and fractured limestone. A common misconception about aquifers is that they are underground rivers or lakes. While groundwater can seep into or out of aquifers due to their porous nature, it cannot move fast enough to flow like a river. The rate at which groundwater moves through an aquifer varies depending on the rock’s permeability. Groundwater can become depleted if we use it at a faster rate than it can replenish itself. Aquifers naturally filter groundwater by forcing it to pass through small pores and between sediments, which helps to remove substances from the water. This natural filtration process, however, may not be enough to remove all of the contaminants. We have covered more specific geographies in more detail on separate links, see below.