Karst country: why northeast Iowa water runs so hard

Iowa's hardness has a geological signature. Across the northeast, the landscape is limestone and dolomite karst — fractured, cave-riddled rock that groundwater moves through and dissolves as it goes. The result is water in the 6 to 17 grains per gallon range, hard to very hard depending on your source. Des Moines treats and softens its supply down to under about 8.76 gpg, but places like Hiawatha near Cedar Rapids draw water closer to 17 gpg, and raw well water can run higher still.

Scale and the Iowa water heater

Warm Iowa's calcium- and magnesium-rich water and those minerals precipitate out onto the hottest surface in the appliance. That's the definition of scale, and it behaves like insulation your heater never asked for:

• At about a quarter-inch thick, scale on the elements or tank bottom can drop heating efficiency 25 to 40%.
• Tankless heat exchangers, with their slim internal passages, foul faster at the high end of Iowa's range and need descaling more often.
• Tank-style heaters build a sediment layer that can rumble, waste energy, and shorten the unit's usable life.

The higher your local number, the sooner you'll notice it — and in the very-hard pockets of Iowa, that can be within a couple of years.

Wells, iron, and knowing your number

Iowa has a lot of private-well households, and this is where two things collide: very hard water and iron. Raw well water in the karst regions often carries both. Municipal customers in Des Moines and other softened systems are on the gentler end; untreated well users are on the harsh end. If you're on a well, get a hardness and iron test before you spend a dime — iron staining is a separate problem that a scale conditioner will not fix.

Being straight with you: what we sell is a salt-free conditioner, not a softener. It does not remove hardness or iron from your water, and it won't dissolve scale that's already in your heater. It helps keep new scale from bonding to hot surfaces, protecting your heater's efficiency going forward.

Here's the right-sized salt-free scale protection for your Iowa water heater:

Salt-free conditioners reduce and help prevent new water-heater scale; they are not softeners and do not remove existing hardness. Free U.S. shipping. See our hard water guide.