Water Facts

See also... Water Treatment Devices

Reverse Osmosis

Reverse Osmosis (RO) systems can reduce levels of many substances that may be in water, like those that cause foul tastes, smells, or colors, and substances that may cause adverse health effects in some susceptible populations. They also remove fluoride and the minerals associated with “hard” water. RO involves the movement of water through a membrane with microscopic openings that allow water molecules to pass through. Because this process is relatively expensive, RO systems are generally used only to treat drinking and cooking water supplies. A drawback to RO units is that most “waste” several gallons of water for each gallon they produce (that is, they generally recover only a small percentage of the water entering the unit; the remainder is sent to the sanitary sewer system). However, RO units can vary dramatically in this regard, and there are high-efficiency models available.

RO systems can lower the pH of water to below state and federal standards. RO systems also remove benefi cial minerals such as calcium, magnesium and fl uoride. Removal of these minerals along with the lower pH makes the water similar to distilled water. Thus, some consumers may not like the taste of RO water. Sampling RO water is recommended before purchasing this equipment. RO systems are usually installed below the kitchen sink. RO systems consist of the pre-fi lter, RO membrane unit, a pressurized storage tank for the treated water, a post-fi lter, and a separate delivery tap for the treated water supply. Because these components require a signifi cant amount of space, available room beneath the sink should be considered.

When comparing purchase to lease/rent options, consider the initial costs of the system. RO units range in cost from less than $300 to $3,000 or more. Installation and maintenance costs can vary and should be a factor when deciding on a system.

Water Softeners

Water dissolves rocks and minerals, releasing calcium and magnesium ions that cause water to be “hard.” Water softeners will remove nearly all these ions from the water. They typically treat all of the water coming into the home.

Hardness of Water Chart

Hard water can be a real pain, but it is not a health issue. Water softening is popular because most people prefer softened water for bathing, cleaning and washing. In addition to leaving chalky deposits on faucets and other fixtures, hard water interferes with many household-cleaning tasks (laundry, dishwashing, etc.)

While household appliances, including water heaters, may be adversely affected by hard water (see the hardness table above), problems can be easily avoided by proper maintenance and cleaning. For example, draining some water from hot water tanks removes deposits.

Water can be softened by a process called ion exchange. Sodium (or potassium) ions are used to coat an exchange medium in the softener. As hard water passes through the unit, the water “trades” its calcium and magnesium for the sodium or potassium. Water softeners are classified in five different categories: manual, semiautomatic, automatic, demand-initiated regeneration (DIR), and off-site regeneration. In terms of efficiency, DIR units are considered desirable because they regenerate only after a certain volume of water has been processed. Retail prices for home water softeners may range from a few hundred to several thousand dollars, depending on the size and type of softener. The cost of salt to replenish the brine solution is approximately $5 to $7 per month, depending on the form purchased.

Advantages of water softeners include improved “feel” on skin when bathing (subjective); cleaner, softer clothes; longer life of some appliances; reduced use of household cleaning products; and reduction of water spots and deposits. Disadvantages of water softeners include increased sodium, which may concern some people on restrictive diets (check with your doctor about this issue); harm to houseplants because of elevated salt content; and overload or reduced effectiveness of septic systems.

There are several alternatives to reduce problems associated with hard water. They include laundry detergents that contain water-softening agents; dishwasher rinse aids; bath salts; and lime- or mineraldissolving household cleaners. Deposits on fixtures and countertops can be prevented by wiping surfaces dry; mineral residue on surfaces only occurs when water is allowed to evaporate.

Other technologies, called water “conditioners,” are marketed as salt-free alternatives to softeners. Consumers must decide individually on the validity of these claims. It should be noted that neither the American Water Works Association nor the Water Quality Association endorses these technologies.