Metropolitan Water District of Southern California, one of the world's largest water agencies, wholesales water, either directly or through a member agency, to the local utilities that serve more than 18 million Southern Californians. Undeniably, water quality is a major issue to Southern California. In pursuit of high-quality water, Metropolitan is at the forefront of the water industry. When asked, "Is the water safe?" it can answer loud and clear: You bet it is.

A Not So Trivial Pursuit: Pure Water

If their streams turned muddy or brackish, our tribal ancestors packed up their belongings and moved. [With an importance second only to that of air, the quest for water quality is as old as thirst.]

A collection of medical lore written in Sanskrit 4,000 years ago is credited with the suggestion that "It is good to keep water in copper vessels, to expose it to sunlight and filter it through charcoal." Excellent advice, even today.

On the walls of an Egyptian tomb dated to 1450 B.C. are the depictions of the process by which liquids are stored until solids have settled, then siphoned into another container, leaving the sediment behind.

But until the 19th century, water quality efforts were individual. Little attempt was made to treat public water supplies until English engineer James Simpson introduced slow-sand filtration and the first large-scale treatment plant was built in 1892 to purify Thames River water.

When the London cholera epidemic of 1854 was traced to a public well, water quality became an utmost importance. The value of water treatment was dramatically proven in 1892 when Altona, Germany, thanks to its filtration system, escaped the cholera epidemic that ravaged neighboring Hamburg.

With the discovery of bacteria and the realization that specific ailments could be transmitted through water, the public soon accepted the need to treat water. Chlorine was first used to disinfect water in England in 1897. Widespread use of disinfectant drastically reduced outbreaks of cholera, dysentery, typhoid fever and other diseases.

When Metropolitan Water District began operating its distribution system in 1941, water quality test calculations were laboriously worked out by hand. The Weymouth filtration plant used chloramines, a combination of chlorine and ammonia as a disinfectant to treat water.

Six months later, America went to war. The country ran short of ammonia and Met turned to the free-chlorine treatment, which it continued to use until the presence of trihalomethanes, organic compounds no one had heard of in the 1940s, made a return to chloramines necessary in late 1984.

Today, Metropolitan processes water through its five filtration plants, delivering potable--drinkable--water as defined by standards set by the U.S. Environmental Protection Agency and the state of California. More than 200 tests identify and measure compounds the Egyptians never dreamed existed.

This isn't the end of a 4,000-year pursuit of pure water. Far from it. This is the threshold of an era of water refinement.

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