An insidious home invader attacks pipes, shortens the life of appliances
By Debra Sass

A valuable Greek slave was once said to be "worth his weight in salt." Being seated "above the salt" at a dinner table in Europe signaled a place of honor. Magical powers have been ascribed to it and religion considers it sacred. Salt has been used as currency, as medicine and as a status symbol.

It's also been linked to hypertension, high blood pressure, heart and kidney disease and stroke.

Depending on how you use it, or where you find it, salt can be a good thing or a bad thing.

It turns out that human blood contains 0.9 percent salt. Salt breaks down into 40 percent sodium and 60 percent chloride making it the principal source of sodium in our diet. Salt helps maintain a stable balance of water and sodium in our body that allows cells to regulate fluids and transmit electrical impulses through the nervous system and muscles.

But just as high salt levels impact the body's inner gears, it does likewise with some of our workhorse home appliances.


Water high in salinity contains a lot of total dissolved solids or TDS. Salinity, or TDS, is a measure of mineral salts dissolved in water that typically include calcium, magnesium, sulfate, and chloride.

Water high in TDS can be harsh on home plumbing systems and fixtures causing early corrosion of pipes, scaling and spotting, reduced lifespan of appliances, and greater use of cleaning products such as soap and detergent. These sodium side-effects add up to millions of dollars in replacement costs, according to a 1999 study conducted by Metropolitan Water District of Southern California, done in collaboration with the U.S. Bureau of Reclamation, State Department of Water Resources and Metropolitan's member agencies.

The two-and-one-half year technical investigation looks at the effect of TDS on the coastal plain of Southern California through an economic assessment model. The Salinity Management Study focused on the impacts to residential, commercial, industrial and agricultural water customers as well as to utilities, groundwater and recycled water projects.

The study found that there would be annual $95 million benefit to the region if imported water supplies had a 100-milligram per liter decrease in current salinity levels. Residential benefits alone would amount to $35 million. Where do these savings come from? They come from such unassuming appliances as your washing machine and water heater, faucets and garbage disposal. Simply put, less salt in your water supply means less wear and tear on your appliances and a longer machine life.

According to Metropolitan's Ray Mohktari, study project engineer, TDS levels in water served by Metropolitan vary greatly.

"TDS values in water served to our customers varies throughout the service area," he explained. "Some areas draw their water supplies from sources that are lower in TDS, such as groundwater and water from the northern California's State Water Project, while others rely more heavily on Colorado River water, which is traditionally higher in TDS."

Typically, TDS values of regional water supplies range from 250 to 650 milligrams per liter, he said. A difference of a 100 milligrams per liter in water can mean a longer life for household appliances and can even slow the trend to purchase bottled or vended water and home filtration devices, the study found. (See chart)

Water pipes, water heaters, faucets, the garbage disposal, clothes and dish washers are all vulnerable to TDS. The study found that all appliances experience some reduction in useful life when TDS levels climb.

Most homeowners would like to get a few more years out of their water heater and washing machines; replacement costs of such appliances are usually a significant expense.


Taking the brunt of TDS burnout are water pipes that require replacement
14 months earlier than under normal conditions. This amounts to an annual household cost of 70 cents (in 2002 dollars). Water heaters, clothes and dishwashers will need replacement four months earlier, faucets and garbage disposals two months earlier. And while the annual cost per household amounts to little more than $5 for the combination of each of the six items, when the number is multiplied by 5.5 million households in the Metropolitan service area, the total impacts rise to $29 million per year.

To get an idea on how increasing TDS levels correlate to decreased appliance life, the study authors juxtaposed the useful life of appliances in years to TDS levels ranging from 100 to 1,000 milligrams per liter. Water pipes, for example, have a lifespan of 29.5 years at TDS levels of 300. This drops to 26.6 years when levels rise to 400 milligrams per liter (which is fairly typical for some areas of the service area such as parts of the city of Los Angeles and the Inland Empire). Garbage disposals will last 8.2 years at TDS levels of 300, but wear out a year sooner at TDS levels of 400.
(See Chart).

Coy Burch, a 20-year plumbing veteran based in the San Fernando Valley and owner of ABCO Plumbing, confirms that appliances take a beating from water high in salt.

"It's like driving your car through the desert in a sand storm," he explains. "It's going to get some damage."

Burch said the salt and lime build-up is very hard on both galvanized and copper plumbing. "It's chewing away on the inside of the pipes."

Lime forms in hot water heaters, boilers, sinks, shower enclosures and other appliances because of certain chemical compounds in the water that form when both rain water and surface water come in contact with limestone in the earth. The limestone is naturally dissolved and the minerals contribute to the "hardness" of the water. Heated hard water forms a scale of calcium and magnesium minerals which are limescale deposits.

Water that is considered "hard" is high in dissolved minerals. Because water is a universal solvent, it has the ability of moving through soil and rock and dissolving very small amounts of minerals that it holds in solution. Calcium and magnesium are the two most common minerals that make water "hard."

About 9 percent of Burch's business is related to problems associated with hard water and corrosion. He recounted a recent re-piping job—"It's like hardening of the arteries where things just close up." On that job they removed a section of corroded pipe and on close exam by holding the pipe up to the light, couldn't even see how water had passed through at all.
Hard water is not a health risk, but it is a nuisance because of the mineral buildup it causes and its effect on the performance of soap and detergents.

Hard water also affects water heaters, the main stream of plumbing that provides service to each fixture, showerheads and toilets, according to Burch.

"I'll install new toilets in a home and be called back only a few years later with the complaint that the toilets aren't working very well," Burch said. "The reason is that the hard water has worn down the perforated sides of the toilet that help move water through."

In addition to a reduced life of water-using appliances and plumbing, water high in TDS has corollary impacts related to the purchase of dispensed water and home water treatment devices.

A 1998 investigation conducted on Metropolitan's behalf found that bottled water use increases as TDS levels rise. Also, more households tend to purchase and install water softeners and filter systems as TDS levels rise in tap water.

That study estimated that households with home water softeners pay about $350 each year to avoid the effects of hard water. Similarly, households that buy an alternative to tap water, or install a filtration system, spend about $70 annually. While some softeners exchange minerals to make the water less hard, they add sodium to the household discharge, pushing up the cost of wastewater treatment and increasing salinity levels in groundwater basins.

While salt folklore attaches all sorts of wonderful powers to the grainy substance, it is anything but magical when it builds up in your pipes and toilets and faucets. Worth its weight in salt? No. Pouring salt in a wound is more like it, according to water resource planners.