Long Island gets its drinking water from a system of aquifers - huge underground layers of sand and gravel that contain trillions of gallons of fresh water. It is interesting to note that Long Island is one of the few areas in the country that obtains its sole source of water from aquifers - most areas utilize open surface reservoirs.

Long Island's underground aquifers, constantly replenished by precipitation, have unique benefits as well as potential problems that must always be taken into consideration. Because rainwater seeps through hundreds of feet of soil and closely packed natural particles before reaching the aquifers, it gets thoroughly filtered. This natural process cleanses the water of most impurities.

However, with close to three million residents living and conducting business and industrial activities above the water supply, there is always the possibility that a contaminant of one sort or another may seep through the ground and reach the aquifers. To help guard against groundwater contamination, both the federal government and New York state have enacted strict groundwater protection regulations, including chemical and hazardous materials storage guidelines, zoning laws that prohibit a variety of industries from locating within the "deep recharge" areas that feed the aquifers, and tough sewage treatment requirements. In fact, due to these tough environmental laws, the relatively small amount of contamination that has appeared on Long Island today is mostly traceable to contamination from industrial discharges, fertilizers and pesticides used over two decades ago.

Over the past decade, federal and New York state environmental agencies, as well as New York state and Nassau County health departments, have greatly strengthened drinking water regulations. Today, the Plainview Water District is required, as are all public water suppliers on Long Island, to test all its supply wells four times per year for up to 144 parameters, including volatile organic chemicals, inorganics, pesticides and herbicides (water quality prior to treatment). The tests are conducted by an independent, state certified laboratory with results sent directly to the Nassau County Health Department, which also conducts regular spot checks on its own. Results of these tests are published each year in an Annual Water Supply Statement Supplement which is available at Plainview Water District Office.

The Water District's distribution system (the water that is delivered to residences and businesses, after treatment) is also aggressively monitored on a routine basis, as required by law. A minimum of two times per year, lab samples for 63 volatile organics and 31 inorganic and physical constituents are drawn from multiple locations in the distribution system for analysis. Additionally, sampling is done for lead, copper and physical and corrosivity characteristics. A summary of the results of these tests is what is published in the Water District's Annual Water Supply Statement.

Lab samples are obtained once each week at multiple locations in the distribution system and analyzed for bacteria and chlorine residual. The Plainview Water District also monitors pH and chlorine levels on a 24-hour a day basis with automated equipment at select locations. Daily manual checks of pH and chlorine levels are also taken as a cross-check against automated reading levels.

The maximum levels of substances allowed in the water delivered to residents and businesses in the Plainview Water District's service area are established by the federal government and New York state. In fact, New York state regulations exceed federal regulations and are considered equal to the toughest water standards found anywhere in the country.

In New York state, the permissible level of volatile organics (carbon-based constituents) is five parts per billion. To put this in perspective, five parts per billion is the equivalent of one second in 32 years! The Annual Water Supply Statement summarizes testing for 33 volatile organics.

The permissible level for inorganic constituents (non-carbon based) depends upon the constituent. The Annual Water Supply Statement summarizes testing for 31 inorganic and physical parameters. For most of these parameters, maximum levels are set in parts per million. There are nine primary inorganics; cadmium, lead, mercury, selenium, arsenic, chromium, silver, beryllium and thalium for which permissible levels are set in parts per billion. For two inorganics; ammonia and foaming agents (also known as detergents), no maximum level has been established.

Standards are set based on two primary factors: the maximum level of any constituent determined to be safe for humans and the analytic limit that can be detected reliably by current technology. "Safe" levels are established by the United States Environmental Protection Agency (EPA) based on a rigorous protocol of tests. The levels established, called MCL's (maximum contaminant level), are enforceable standards based on current testing technology.

Should acceptable levels be set even more stringent than current standards? The exhaustive testing protocols used by the United States EPA result in standards that represent those levels at which a contaminant presents an infinitesimal risk to humans. For sure, driving a car presents a far greater risk to an individual's health and safety than a contaminant in the water supply at or below its established MCL. Does this mean there is absolutely no risk? No. For there to be absolutely no risk, acceptable contaminant levels would all have to be set at zero, and this is scientifically unfounded as well as technologically unenforceable. There will always be traces, no matter how minute, of inorganic and organic constituents in water - the world is not a "surgically sterile" environment. Additionally, the cost to develop testing technology that would be able to reliably test for zero levels would far outweigh the benefit of such technology.

The water delivered to homes and businesses in the Plainview Water District's service area meets or exceeds current federal, state and county standards. Based on this fact, people can feel secure and confident in the water delivered to their homes and businesses by the Plainview Water District.