Storm Lake Drinking Water

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Where Does My Water Come From?
Iowa Department of natural resources-,d.b2I

The City of Storm Lake’s drinking water comes from 10 water wells located in a variety of aquifers. An aquifer is an underground layer that is very permeable and porous that water moves through easily. Most aquifers are made of sandstone, fractured limestone or unconsolidated (looser, un-packed) sand or gravel. To get to an aquifer, you must drill through the material from the surface to the aquifer (the layer where the water is being stored). Aquifers are recharged (refilled with water) over time through precipitation falling on the surface and the water making its way down through the porous rock to the aquifer. Some aquifer recharge is from hundreds of miles away where the aquifer is closer to the surface. The recharge rate of aquifers is important because if you are pumping out water faster than the recharge rate, the water level in the aquifer will fall and may eventually run dry.

There are 3 aquifers that are used for drinking water for Storm Lake- The Glacial/Pleistocene aquifer at 80-120 feet deep (7 wells), the Dakota Sandstone aquifer at 450-500 feet deep (2 wells), and the Jordan aquifer at 1500 feet deep (1 well). Two of the Glacial/Pleistocene wells are the newest. They went into service in 2007 and 2009. A new Dakota Sandstone well is projected for the summer of 2014 to bring the total well count to 11 and ensure the City’s water supply into the future.

How Do We Treat Your Water?
Water treatment consists of several different treatment processes. These vary from community to community, depending on the source of the water and the characteristics of the untreated water. Storm Lake uses only aquifer water (a ground water source), which is generally less contaminated then surface water. The first step is softening, which removes some of the hardness (calcium and magnesium) and iron in the water. Very hard water is generally bad for appliances that use it, tends to leave spots and residue when it dries and has a very distinctive flavor when drinking it although some hardness is desirable for proper water stability. Adjustment of pH is done so the water is not too basic or acidic. Water that is to basic can cause digestive problems, while water that is to acidic can corrode pipes and water fixtures. MIOX, a chlorine solution, is added for disinfection to kill bacteria and pathogens that may be in the water. Fluoride is added to the water to promote dental health. Fluoride treatment of water helps prevent cavities in the children who are drinking from it.

Treated water is then contained in storage tanks. Storm Lake has underground storage tanks for 1.675 million gallons of water and water towers for another 1.75 million gallons.

For more information please see:
Iowa's Groundwater Basics
2012 Annual Water Quality Report for Storm Lake