Water Hardness

Your water is groundwater, and groundwater is naturally high in mineral content, making it "hard."

Hard water is not a health hazard. The United States Environmental Protection Agency (USEPA) establishes standards for drinking water, Primary Standards - based on health considerations, and Secondary Standards - based on the aesthetic properties of water. There is no Primary or Secondary Standard for water hardness.

Calcium and Magnesium dissolved in water are the two most common minerals that make water "hard." Water hardness is expressed as the amount of Calcium Carbonate (CaCO3) measured in the water and can be communicated using any one of the following units:

  • Milligrams per liter (mg/L)
  • Parts per million (ppm)
  • Grains per gallon (gpg)

One grain per gallon of hardness equals 17.1 mg/L or ppm of hardness. (Note: mg/L = ppm)

Classification of Water Hardness (United States Geologic Survey, USGS)

Classification Milligrams per liter (mg/L) or parts per million (ppm)Grains per gallon (gpg)
Soft0 to 600 to 3.5
Moderately Hard61 to 1203.5  7.0 to
Hard121 to 1807.0  10.5 to
Very HardOver 180Over 10.5

Soquel Creek Water District's water hardness is classified as hard to very hard.

Groundwater Sources

The District pumps groundwater from several different sources (wells) positioned throughout the District's service area. Not all wells are actively pumping at the same time, and since each well has its own baseline hardness value, each service area has a range of hardness values as follows (based on 2017 water hardness data):

  • In the District's western-most areas of Capitola/Soquel — from about 41st Avenue to Park Avenue — the range of water hardness is about 150 to 370 parts per million (ppm), or 9 to 22 grains per gallon (gpg)
  • In the Soquel/Aptos areas of the District — from about Park Avenue to State Park Drive — the range of water hardness is about 140 to 300 ppm, or 8 to 17.5 gpg
  • In Aptos/Rio del Mar areas of the District — from about State Park Drive to Mar Monte Avenue — the range of water hardness is about 150 to 200 ppm, or 9 to 12 gpg
  • In the La Selva Beach area — from about March Monte Avenue to Sand Dollar Drive — the range of water hardness is about 100 to 200 ppm, or 6 to 12 gpg

Water Softeners

If you choose to utilize a water softener, the USEPA recommends the selection of a device that is certified by one of the following three organizations, which are accredited by the American National Standards Institute (ANSI):