LV Valley water meets federal health standards, district says

Monday, June 20, 2005 | 8:51 a.m.

A whiff of tap water may smell like chlorine in a swimming pool, but according to the Las Vegas Valley Water District's annual report sent to its customers, the water meets or exceeds all federal and state regulations for a healthy drink.

The Water District tests for about 150 regulated and unregulated contaminants to deliver safe water and keep residents and visitors healthy, the report said.

This year's report contains test results based on almost 40,000 water samples collected from around the valley and analyzed in 2004.

Southern Nevada Water Authority, the regional agency that delivers water to Clark County and city residents, has two advanced water treatment plants designed to provide safe drinking water.

Water drawn from Lake Mead is sent to either the Alfred Merritt Smith Water Treatment Facility, which began delivering water in 1970, or the River Mountains Water Treatment Plant, open in 2002.

In addition to studying water for signs of heavy metals or other contaminants, the Water Authority monitors cryptosporidium, methyl tertiary butyl ether (MTBE) and perchlorate, which are not listed in the Safe Drinking Water Act amended in 1995.

Cryptospiridium is a single-celled organism that occurs in 95 percent of all U.S. surface waters and cannot be killed by chlorine. A Las Vegas outbreak in 1994 killed 32 residents and sickened another 132 people.

MTBE is a chemical used in gasoline to reduce smog. It has become a major environmental concern after it was detected in groundwater. It has never been detected in Las Vegas.

Perchlorate, a man-made salt, has been detected in Lake Mead after two plants manufactured ammonium perchlorate to boost rocket and shuttle engine performances. There are no federal standards for perchlorate in drinking water. The average perchlorate level in Las Vegas water in 2004 was less than 6 parts per billion. Most home reverse-osmosis systems treating Lake Mead water reduce concentrations below detectable levels.

The two water treatment plants use both ozonation and chlorine to kill organisms such as cryptosporidium and viruses, the report said.

Water drawn from Lake Mead flows into sealed chambers where thousands of diffusers release ozone gas up through the water, where the ozone disinfects the water.

The water district also adds chlorine to the drinking water, equal to 1 cent in a $10,000 pile of coins, to further disinfect the water.