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Two main causes of hard water are the minerals magnesium and calcium. Water is considered "hard" if the mineral grains per gallon (gpg) are in excess of 7 gpg. Many homeowners treat their hard water with water softening systems to lower the mineral content, producing less damage overall from deposits along faucets and water appliances.
The majority of water sources throughout the world come from groundwater, which flows through rocks, eventually depositing minerals into the flowing liquid. The groundwater feeds municipal water supplies that ultimately flow to homes and businesses. Both calcium and magnesium create scaling deposits along water routes, such as pipes, that can clog over time.
The mineral causes of hard water produce the layered deposits seen on water faucet heads. Over time, magnesium and calcium adhere to shower heads and faucets, building up on the surface of the fixtures as the water passes through them. Mineral accumulation causes poor water pressure at the faucet or shower, creating strain on the plumbing system.
This mineral accumulation is not exclusive to just faucets. These causes of hard water also affect water heating equipment. Heating elements within boilers or hot water heaters can have layered mineral deposits as well. Homeowners may observe that their heating bills increase each month. The slow mineral layer accumulation across the internal heating element hinders the overall operation, resulting in more energy expenditures to create the same level of warmth throughout the home.
A common solution to the mineral causes of hard water is cation exchange treatment. Both calcium and magnesium are attracted to a resin bed full of sodium ions. The sodium ions replace the calcium and magnesium ions within the water since the minerals become attracted to the positively charged resin bed. As a result, the water lacks the hardening minerals as it flows into the home's plumbing system.
Most water municipalities do not soften the water for the surrounding community. Aside from creating extremely expensive water bills, water companies realize that not all water requires treatment. Some water is used to water lawns or wash sidewalks, which does not require any softening strategies. Homeowners must therefore make their own choices about whether and how to stop the causes of hard water within the home.
The negative impact of hard water can be easily observed, which makes it easier for homeowners to determine if water softening is necessary. For example, washing clothes may require more detergent with excessive hard water since the minerals impede the cleaning properties of the soap. In addition, soap scum may be difficult to remove from both the shower and the skin, resulting in a dirty bathroom and pale complexion.