Water Contaminants & Remedies
If you object to the chlorine taste of your tap water, try placing the water in an uncovered pitcher in the refrigerator overnight. This will reduce the chlorine taste. Most tap water is treated with chlorine to kill disease causing microbes and other water contaminants.
Water systems use chlorine because it is an effective disinfectant for viruses and bacteria, and because it continues to disinfect water as it travels through pipes.
If you have tested your water and know that it has high levels of lead, or if your home has lead pipes, flush the cold water tap by running it until it becomes cold if the water hasn’t been used for several hours. Lead accumulates after extended contact with lead pipes. You may use this flushed water to water plants and do other household chores.
If you have a contaminated private well, have special health needs or in an emergency situation such as a flood, boil water for one minute to kill microbes (or three minutes at altitudes greater than one mile) and place in a clean, covered container.
How Filters Work?
A water filter is composed of a screen with many microscopic holes. The smaller the holes, the more water contaminants the filter can remove. Filter holes are measured in microns. (The period at the end of this sentence is 500 microns.)
When considering filter size, look for an absolute (the largest hole), not a nominal (the average hole), rating. EPA and CDC recommend an absolute one micron filter (or one labeled for cyst removal) to remove Cryptosporidium.
Some water contaminants and their size in microns:
- Giardia lamblia – 8 to 12 microns
- Cryptosporidium parvum – 4 to 6 microns
- Bacteria (such as E. coli and salmonella) – 0.2 to 4 microns
- Viruses – 0.004 to 0.1 microns (Generally, only a few filters, such as ultra-filters and reverse osmosis, have holes small enough to assure removal of all viruses. However, viruses can be killed using a disinfectant).
Removing Specific Contaminants
Giardia and Cryptosporidium – distillation, reverse osmosis, absolute one micron filters, ultraviolet light, and filters certified for cyst removal. Bacteria and viruses – distillation, reverse osmosis, ultraviolet light, and disinfection.
- Arsenic – adsorptive media Disinfection byproducts – point-of-entry adsorptive media systems distillation, aeration, carbon filtration and reverse osmosis.
- Lead – distillation, reverse osmosis and some carbon filters.
- Nitrates – distillation, reverse osmosis or ion exchange.
- Pesticides – some carbon filters.
- Radium – ion exchange, distillation or reverse osmosis.
- Radon – activated carbon filter and aeration.
People With Severely Compromised Immune Systems
Some people may wish to take special precautions with the water they drink. In particular, people with immune systems that are weakened by AIDS, chemotherapy or transplant medications are more vulnerable to microbial contaminants in drinking water such as Cryptosporidium.
Cryptosporidium is a microscopic parasite that lives in the intestine of infected animals and humans. It passes in the stool in its dormant oocyst form. The oocyst is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine-based disinfectants.
It occurs mainly in surface water sources, such as lakes, streams and rivers. In healthy adults, Cryptosporidium can cause illness, but for people with weakened immune systems, it can cause severe illness and even death.
Those who wish to take extra measures to avoid waterborne cryptosporidiosis can bring their drinking water to a boil for a full minute. Boiling water is the most effective way of killing Cryptosporidium. As an alternative to boiling water, people may take the following measures.
Use a point-of-use filter
Consider using point-of-use (personal use, end-of-tap, under sink) filters that remove particles one micrometer or less in diameter.
Filters that use reverse osmosis, those labeled as “absolute one micron filters,” or those labeled as certified by an American National Standards Institute (ANSI) – accredited organization to ANSI/NSF Standard 53 for “Cyst Removal” provide the greatest assurance of removing Cryptosporidium.
As with all filters, follow the manufacturer’s instructions for filter use and replacement.
Use bottled water
Check the label or call the bottler to find out how bottled water is treated. The following bottled water treatments protect against Cryptosporidium: reverse osmosis, distillation, ultraviolet light, or filtration with an absolute one micron filter.
Bottled waters derived from protected well and spring water sources are less likely to be contaminated by Cryptosporidium than those containing untreated municipal drinking water from less protected sources such as rivers and lakes.
Those who choose to take these precautions should remember that they can be exposed to waterborne pathogens through water used for brushing teeth, making ice cubes, and washing fruits and vegetables – not just through water they drink.