What is Hard Water?
Calcium and magnesium leach back out of the water wherever it constantly flows, so you’ll see a yellow-white crust forming on faucets, around pipe joins and inside of your coffeemaker and dishwasher. You can use white vinegar periodically to clean these appliances, but the buildup will come back.
Minerals in water also tend to bond with the molecules in soap, producing a scum-like substance sometimes called “soap curd” that builds up on shower curtains and leaves a film on glassware in the dishwasher. This chemical bonding also reduces the amount of soap molecules available to form a lather – which means you must use more soap to get the job done.
If you have municipal water, you can start by calling the water company since all water coming out of the plant would be about the same. You can also buy an inexpensive kit from the hardware store to take your own measurements – and while you’re at it you can test for other factors such a pH, bacteria, etc.
A reading of 7 mineral grains per gallon (or 121 parts per million) is considered “hard” water, though even with lower concentrations, you may still see symptoms such as crust forming in the dishwasher or coffeemaker and soap scum buildup in the shower.
How Softeners work
In high school chemistry class, you learned that elements can have positive or negative charges, and molecules are formed based on those attractions.
For example, Hydrogen has one positive charge while Oxygen has two negative charges. That’s why water molecules (H2O) are made of two Hydrogen atoms and one Oxygen atom. Calcium and Magnesium each have positive charges, so water “softeners” were designed to use a negative chemical attraction to snatch these positive elements out of the water.
Usually, this is accomplished using a network of negatively-charged plastic beads through which the water passes. The beads are coated with sodium ions that have a single positive charge, so they are easily displaced by the Calcium and Magnesium ions that each have two positive charges. The calcium and magnesium ions cling to the beads, exchanging places with the sodium ions that are carried off by the water.
Eventually, the beads have no more sodium to exchange and the softening process stops working. Therefore, your water softener is set to “recharge” overnight. Brine water from the salt tank washes over the beads. The mineral deposits are washed down the drain, and the beads are resupplied with sodium ions for another day.
Health experts say the amount of sodium in softened water is generally too small to be an issue. However, people who need to entirely remove sodium from their diets should consult a doctor before deciding how to proceed.
One option is to have the plumber leave the kitchen sink out of the loop served by the water heater. Another would be to use bottled water for consumption and tap water for cleaning and other household purposes. Sodium can also be taken out of the water-softening equation altogether by switching to potassium chloride instead of sodium as a water softening agent.
If you want to switch to potassium chloride pellets instead of salt pellets for your water softer, you can do so easily. No change to your equipment is needed. You can simply buy the alternative pellets and refill your water softener tank as normal.
The main reason for doing so would be to eliminate the presence of sodium in your tap water. However, using potassium chloride pellets generally costs about three times as much as salt. Bags of potassium chloride pellets may be a little harder to find, but major hardware stores typically carry them.
Scams to Avoid
Beware of alternative devices that claim to use magnetism to detach mineral ions from the water. Independent scientific tests have repeatedly demonstrated that these systems do not work.