An associate of mine met recently with an expert from the Los Angeles Department of Water and Power. He was shocked to learn that 70 percent of the people in the L.A. area drink only filtered water or bottled water.

With this growing demand for higher quality drinking water, it's no surprise that homeowners are buying and installing the same technology used by the major bottled water companies.

Reverse osmosis, or simply RO, is the filtration process used by major bottling companies like Coca Cola, producer of the Desani brand, and Pepsi, for their Aquafina.

Consumer demand for water purification and filtration has become the driving force for a relatively new and fast-paced industry. Concerned consumers are responding to the broadly reported knowledge that more contaminants are being found in our water every day. Your customers can have the finest drinking water available at the tap without the high cost and hassle of bottled water.

Reverse osmosis is a process used to purify water while removing salts and many other impurities. The key function of reverse osmosis takes place within a semi-permeable membrane that allows only pure water to pass through it.

Water is nature's smallest liquid molecule at room temperature. It passes with ease through the smallest holes in the RO membrane while all other larger molecules are stopped. That means contaminants are eliminated, vastly improving the purity, color and taste of treated water.

Last year, the Water Quality Association conducted an independent survey that verifies the breadth and scope of their concern. The results show that:

• 86 percent of Americans are concerned about their drinking water.
  
• 70 percent are knowledgeable about contaminants in their water.
  
• 41 percent already use a water treatment device.
  
• 43 percent said filtered water tastes better.
  
• 42 percent said filtered water is safer.
  
• 1 in 3 Americans believe household drinking water isn't as safe as it should be.
  
• 1 in 10 respondents say they plan to purchase a household water treatment system within the next year.

There are very few water sources in the U.S. that challenge the capabilities of an RO system. To operate at a peak performance, the incoming tap water supply should meet the following criteria:

Water temp: 35 degrees F to 85 degrees F max.
Total dissolved solids: 2,000 ppm max.
Iron tolerance: 0.5 ppm max.
Hydrogen sulfide: must be removed.
Silica tolerance: less than 125 ppm.
Hardness: over 15 gpg should be softened.
pH range: 3-11

The key components of an RO system are the following:

• A sediment filter vastly reduces suspended dust, dirt, sand, rust particles and other sediments.

• The activated carbon filter reduces chlorine and volatile organic chemicals such as chlorine and pesticides. It's the main cleanser of water odor and taste.

• The carbon block filter (made of highly compressed grains) performs more of the same carbon filtration, yet with much higher reduction of particulate matter.

• The reverse osmosis filter, the heart of the system, is responsible for rejecting up to 98 percent of the total dissolved solids in the water. It's here where purification takes place. The RO membrane reduces cryptosporidium, giardia, viruses, trihalomethanes, ecoli bacteria, radioactive radon, ethylene glycol (antifreeze), arsenic, copper, iron, lead, chromium, fluoride, radium, manganese, as well as dissolved chemical solids such as bicarbonate, cyanide, ferrocyanide, nitrates and nitrites, fluoride, odor, trihalomethanes, gas additive MTBE, and organic pollutants such as pesticides, EDB, PCB, benzene, TCE, and other taste-and odor-causing compounds.

What happens to the impurities that were in the water? Well, they're typically washed down the drain. Unlike filters, the RO membrane is self-cleaning. As the source water flows through the module, it's divided into two streams. One stream is forced through the membrane by osmonic pressure created by water pressure on each side of the semi-permeable membrane. The second stream carries the rejected salts, dissolved pollutants and contaminates into the drain.

Another facet to the water quality equation today is water conservation. Customers of the Los Angeles Department of Water and Power know all too well that they are dealing with worsening water supply and quality issues as water sources diminish, and the population grows.

Even the best home RO systems use 4 gallons of water for every 1 gallon produced -- and many systems waste as much as 20 gallons just to produce 1 gallon of water.

RO systems can certainly eliminate many water conditions your customers don't want. Be sure to consider, however, how much water is "wasted" in the process of cleaning it up.

Facts About Water

Approximately 75 percent of U.S. households have chlorinated water. A 1987 study sponsored by the National Cancer Institute, Food and Drug Administration, and EPA found increased risk of bladder cancer with the long-term consumption of chlorinated drinking water.

Millions of private and public wells have never been tested for contamination, but a five-year, $12 million, nationwide survey was conducted by the EPA and released in 1990. Based on that survey, the EPA estimates that 10.4 percent of community wells and 4.2 percent of natural domestic wells have detectable levels of at least one pesticide.

Even bottled water isn't necessarily without contamination. Some bottled water isn't always regularly monitored. In 1990, a bottled water survey by the Suffolk County, New York, health department tested bottled water sold in the county and found that nine of 88 brands tested did not meet state and federal drinking water standards.

According to EPA estimates, 40 million Americans are exposed to levels of lead in water well above the EPA's Maximum Contaminant Level.

Virtually everyone has some level of radon in their water. The national average is 200 to 600 picocuries per liter. At these levels, scientists estimate the risk of developing cancer from radon ingestion is greater than the risk of cancer from most other regulated contaminants found in drinking water at the maximum levels allowed by the EPA.