Hard Water From a Well: Scale, Spots and Dry Skin
White crust on the kettle, spots on glasses, soap that will not lather and a water heater that rumbles. Hardness is calcium and magnesium picked up from limestone and dolomite, and most well water in the country has it.
Likely causes
- Calcium and magnesium dissolved from limestone or dolomite aquifers
- High total dissolved solids
- Iron and manganese adding to scale
Tests to order
- Hardness
- Total dissolved solids
- Iron
- Manganese
- pH
Treatment options
- Ion exchange water softener
- Salt-free conditioner for light scale
- Point-of-use reverse osmosis for drinking water
What the number means
Labs report hardness in grains per gallon or milligrams per liter of calcium carbonate. Under 3 grains (about 50 mg/L) is soft. Seven grains and up is hard, and most limestone-country wells run 10 to 25 grains. At that level a 50-gallon water heater builds a layer of scale every year that cuts its efficiency and its life.
Softener or conditioner
An ion exchange softener is the only thing that removes hardness. It swaps calcium and magnesium for sodium, uses salt and a drain, and costs $1,000 to $2,500 installed. Size it by grains of hardness times gallons used per day; an undersized unit regenerates constantly and wastes salt. Salt-free conditioners do not remove hardness, they change how it crystallizes so it sticks less. They help with light scale and do nothing for spots or lathering.
Two things to check before buying
Iron above 1 mg/L fouls softener resin, so treat iron first or buy a unit rated for it. And if anyone in the house is on a sodium-restricted diet, add a small reverse osmosis unit at the kitchen tap for drinking and cooking, or plumb one cold line around the softener.
Is hard water bad for you?
No. Calcium and magnesium in water are harmless and arguably good for you. Hardness is a problem for appliances, plumbing and skin, not health.
Why does my softened water feel slimy?
That is what clean skin feels like without a film of soap scum. It fades as you get used to it.