Water Contaminants

On August 6, 1996, President Bill Clinton signed the Safe Drinking Water Act Re-authorization with these words:


Unfortunately, over twenty years later, it is still a ‘fundamental promise’. In our highly industrialized society, there are hundreds of sources of water contamination. Drinking water sources are subject to contamination and require appropriate treatment to remove disease-causing agents. The Environmental Protection Agency is charged with overseeing and regulating the quality of our drinking water. The EPA has established ‘acceptable’ standards for only 80 of the toxic bacteria, minerals and other contaminants that pollute both surface and ground water.

Water Contamination

Water contaminants enter the water supply through multiple sources, both natural and human-produced. Just as ground water generally moves slowly, so do contaminants in ground water. Because of this slow movement, contaminants tend to remain concentrated.


The most typical sources of surface water contamination are:

Natural Sources	Deposits of minerals, decaying organisms in water. Examples: Barium, Cadmium, Chromium, Cyanide, Fluoride, Iron, Radium.
Agriculture	Pesticides, irrigation methods, soil contaminants such as nitrates, animal waste
Atmospheric Deposition Air pollution is a major source of water contaminants. As water condenses and becomes precipitation, it may pick up particles from the air and dissolve them. These minerals and other impurities become water contaminants either directly when the rain falls into open bodies of water, or indirectly through runoff and groundwater contamination.	Industrial wastes, incinerated chemicals and wastes, pollutants from emissions from automobiles, etc. including nitrogen, mercury, copper, PCB, chlordane, lead, lindane, diazanon, hexachlorobenzene
Construction Construction of buildings, roads, bridges that disturb the soil	Increased sediments in water
Contaminated Sediments Soils and sands that settle on ocean floors and lake/river bottoms.	PCBs, chemicals from industrial plants, fertilizers, pesticides that may have been used decades ago
Combined Sewer Overflows Old sewer systems that carry both storm water and sewage, designed to overflow into surface streams and rivers as a ‘safety measure.’ Combined sewer systems serve roughly 950 communities with about 40 million people.	Untreated human wastes, industrial waste, toxic materials, debris from sewer systems. See coliform bacteria.
Industrial Point Sources Pollution by industrial sources from discharges, runoff, and land treatment of wastes.	Industrial chemicals, heat which may kill fish and other organisms, contributing to organic pollution
Landfills	Leachate, leached water from waste disposal systems that leaches into groundwater
Marinas and Harbors	Fuel, petroleum products from boat cleaning, fueling, and maintenance, waste water treatment
Municipal Point Sources	Discharges from municipal water treatment plants
Non-point Sources Catch-all term for surface water contamination that happens during runoff, when water runs over city streets, fields, parks, forests etc, on its way to a surface water source	Fertilizer, pesticides, herbicides, oil, grease, toxic chemicals, sediment, salt, acid, bacteria from livestock and pet wastes, faulty septic systems
Septic Systems	Sludge and bacteria leakage
Urban Runoff/Storm Sewers	Sediment, solid waste, decaying vegetation, oil, grease, chemicals from cars, fertilizer and pesticides from gardening, bacteria and viruses, road salts, heavy metals, sediments

Among the contaminants that have raised alarms in recent years are arsenic, lead, copper, mercury, e. coli, and giardia. All of these water contaminants must be removed from water before it is potable or safe to drink. In addition, some of the treatment methods – chlorination in particular – create their own byproducts which are at best unpleasant, and at worst toxic.

Municipal water supplies are required to test their water for as many as 80 different contaminants that have immediate health consequences, but the levels of contaminants allowed in water is not 100% safe for all people. In addition, there is a list of ‘secondary’ contaminants that are suggested for regulation, but are not regulated because their effects are only cosmetic and don’t affect the safety of the drinking water. Finally, there are several dozen more contaminants which have health effects, but which are still under consideration for regulation. It’s no surprise, then, that even the EPA recommends that those with compromised immune systems, children and the elderly take special precautions with public drinking water sources.


Some water testing kits that we offer can be found below:


Created : May 16th, 2013 ; Last updated: July 11th, 2023.