Orange County · hard water guide

Hard water in Orange County.

Hardness in Orange County tap water runs from 230 to 270 mg/L as calcium carbonate across the 36 cities and communities in the latest utility water quality reports. That is 13.5 to 15.8 grains per gallon. All 36 land in the USGS "very hard" range.

Hardness by city

The USGS groups water by how much dissolved calcium and magnesium it carries, measured as calcium carbonate. Up to 60 mg/L counts as soft and 61 to 120 as moderately hard. Water from 121 to 180 is hard, and anything above 180 is very hard. Softener sizing runs in grains per gallon, and one grain per gallon equals 17.1 mg/L.

Three cities and communities share the hardest reading, 270 mg/L. The lowest is 230 mg/L in Costa Mesa, which is still 13.5 grains per gallon. Where a utility report lists more than one hardness figure, the table uses the highest. Where a city is split between utilities, the table follows the utility its FilteredWTR city report uses.

What hard water does to a house

Calcium and magnesium stay dissolved while water is cool and moving. Heat it, or let it dry on a surface, and the minerals come out as white scale. Shower heads and faucet aerators show it first. Inside the water heater, scale and sediment settle on the bottom of the tank and coat the heating element. The Department of Energy recommends flushing water heater tanks periodically because that buildup lowers efficiency and shortens the heater's life.

Hard water also fights soap. The minerals bind with it and leave a film on skin and shower glass, so it takes more shampoo and detergent to work up a lather. In the dishwasher the same minerals dry into spots and a cloudy haze on glassware.

Hardness is a plumbing and appliance problem with no federal health limit. The cost shows up as shorter appliance life and more time spent scrubbing scale.

Softeners and salt-free conditioners

A whole-home softener uses ion exchange. Water passes through a tank of resin beads loaded with sodium or potassium, and the beads trade those for the calcium and magnesium in the water. When the beads fill up, the system rinses them with brine from a salt tank and goes back to work. Softened water stops forming scale and lathers easily.

The upkeep is salt. You refill the brine tank on a schedule, and each rinse cycle sends some water and brine down the drain. Softening adds a small amount of sodium to the water, so some households keep one unsoftened tap in the kitchen for drinking or run potassium chloride in place of salt. Softeners are certified under NSF/ANSI Standard 44.

A salt-free conditioner works another way. Most use template-assisted crystallization, where a treatment media turns dissolved hardness into microscopic crystals that travel through the plumbing with the water. The calcium and magnesium stay in the water. The aim is less scale on hot surfaces such as the water heater, so expect spotting on glass and soap use to stay about where they are today. Ask any seller which independent test backs the scale claim for the exact model you are quoted.

Get the hardness number for your own tap

A utility report gives one figure for a whole service area. At hardness levels like Orange County's, the reading at your own faucet sets the size of the softener you would need and how much salt it will go through. A FilteredWTR tech can measure hardness at your kitchen sink for free and give you the result in grains per gallon on the spot. Bring that number to any softener quote and you can check whether the system on offer is sized for your water.

Sources: U.S. Geological Survey, Hardness of Water (Water Science School) · U.S. Department of Energy, Energy Saver: Water Heating · NSF International / American National Standards Institute, NSF/ANSI Drinking Water Treatment Standards. Hardness figures come from Orange County utility water quality reports compiled by FilteredWTR.

Related guides: Lead in Southern California tap water · Water systems with EPA violations · Chlorine byproducts in Orange County · All city water reports