The water that flows through Arizona’s pipes is generally classified as very hard due to the high concentration of dissolved minerals it contains, primarily calcium and magnesium. This characteristic is a direct result of the state’s unique desert geology and the sources from which it draws its water supply. While the mineral content does not pose a health risk, it creates challenges for homeowners and businesses statewide.
What Makes Water Hard and Arizona’s Classification
Water hardness is scientifically defined by the presence of dissolved divalent cations, mainly calcium and magnesium, which water picks up as it moves through the environment. The concentration of these minerals determines where the water falls on the hardness scale. Hardness is measured in parts per million (ppm) or its equivalent, grains per gallon (GPG), where one GPG equals 17.1 ppm.
The United States Geological Survey (USGS) classifies water with a level above 10.5 GPG (or 180 ppm) as “very hard.” Water supplies for major Arizona metropolitan areas, such as Phoenix and Mesa, often register between 13 to 17 GPG, placing them firmly in the very hard range. This high mineral load is why the water is notorious for its effects on household systems.
Everyday Effects on Homes and Appliances
The most observable consequence of very hard water is the formation of scale, a chalky mineral deposit composed primarily of calcium carbonate. This scale adheres to surfaces like showerheads, faucets, and glassware, leaving behind spots and a cloudy film. Inside appliances, this buildup is destructive, particularly within water heaters where the high temperature accelerates the precipitation of minerals onto the heating element and tank walls.
Mineral scale acts as an insulator, forcing water heaters to use more energy to raise the water temperature, which increases energy costs. Over time, this constant strain reduces the lifespan of major appliances like washing machines and dishwashers. In plumbing, the gradual accumulation of scale within pipes can restrict water flow and lead to reduced water pressure.
Hard water also impacts the effectiveness of cleaning products. The calcium and magnesium ions react with soap and detergent molecules, preventing them from lathering properly and limiting their cleaning capability. This reaction creates a sticky residue known as soap scum, which is difficult to remove from tubs and sinks. Furthermore, bathing in hard water can leave mineral residue on the skin and hair, often resulting in dryness and a lack of luster.
Why Hardness Levels Vary Across Arizona
The pervasive hardness across Arizona is largely attributed to the state’s geology, which features extensive deposits of limestone and gypsum. Water flowing through these mineral-rich rock layers, especially groundwater, dissolves high levels of calcium and magnesium. The arid climate further concentrates these minerals, as there is less rainfall to dilute the water supply.
Water source differences explain why hardness levels are not uniform across the state. Many metropolitan areas rely on the Central Arizona Project (CAP), which delivers water from the Colorado River, a naturally hard source. Areas that primarily use local groundwater wells can experience extremely high hardness levels. However, some communities, often those in mountainous regions or with a different mix of sources, may see lower levels, though they typically still fall into the “hard” category.
Solutions for Managing Hard Water
Homeowners typically address mineral-rich water through two primary methods: traditional water softeners and salt-free water conditioners. Traditional softeners employ a process called ion exchange, where water passes through a resin bed. The resin attracts the positively charged calcium and magnesium ions and exchanges them for sodium ions, physically removing the hardness minerals from the water.
This process results in truly soft water, which enhances the efficiency of soaps and eliminates scale formation throughout the home. Alternatively, salt-free water conditioners, which are more accurately called water descalers, operate differently. These systems, often using Template Assisted Crystallization (TAC), do not remove the minerals.
The TAC process transforms the hardness minerals into tiny, non-adhering crystals. These crystals remain suspended in the water, preventing them from sticking to surfaces and forming scale in pipes and appliances. While a salt-free conditioner can mitigate scale damage, it will not provide the same benefits as a true softener, such as improved soap lathering and the elimination of spots on dishware.