Potential Contaminants
Although the drinking water entering New York City’s distribution system is subject to strict monitoring protocols and meets all federal drinking water quality standards, the potential remains for some contaminants to reach the taps of consumers under certain conditions not related to source water protection. Iron and other forms of sediment can reach taps when water mains break or during maintenance activities on distribution infrastructure. Lead from domestic plumbing, pipes and solder joints in older buildings, as well as copper oxide, can leach into water held in the plumbing and travel to the tap. In addition, residual chlorine can cause taste and odor problems with chlorinated tap water.

Lead can be particularly problematic in New York City drinking water. Many of the older apartment buildings were constructed when lead piping and solder joints were in common use. Not only does lead cause brain damage in children, but there is evidence that the city underreports lead levels in tap water to elude regulators. Most lead can be removed by running cold water from the tap for 30 seconds to flush the domestic plumbing system. Otherwise, lead can be removed by ion exchange, which is accomplished by a variety of countertop filter systems.

Aesthetic contaminants that result in taste, color and odor problems include iron, sediment, and chlorine. Suspended iron and sediment can easily be removed by a simple media filter. Chlorine removal requires an activated carbon filter, which also removes organic solvents like benzene and gasoline.

Filtration Systems
Typical household water filtration systems use faucet/countertop or under counter systems that employ media filters (such as glass fiber), activated carbon, reverse osmosis, or a combination thereof. Media and activated carbon filters in combination are the most popular and economical. It is important to note that basic unit prices of filter systems can be deceptive if the required filters are expensive and/or require frequent replacement. Most brands also offer under counter and whole house filter systems at higher prices than their countertop systems.

Reverse osmosis (RO) is probably unnecessary for NYC apartment dwellers. Although RO removes 4 log (99.99%) of coliform bacteria and 5.8 log (99.9998 %) of cryptosporidium and giardia cysts, even the cheapest Aquasana carbon filter removes 4 log cysts, and chlorination is effective at inactivating coliform bacteria. Because the New York City Department of Environmental Protection (DEP) routinely monitors and disinfects distribution water, these pathogens should not be considered the most worrisome pollutants in city tap water; it is unlikely that a homeowner would require such sophisticated end-of-pipe pathogen removal (and in the rare event that the city were to issue a boil water notice, it is also unlikely that homeowners would trust their filter systems enough not to boil water or switch to bottled water during the notice period.) Also, lead removal efficiency of RO is the same as for Aquasana (99.99%), but a typical RO system retails for $300 plus filters.

Small, portable filter inserts are available for water bottles and sport bottles in the event that people draw water from unfiltered taps. Some of these employ combination media/activated carbon filters, similar to the countertop systems and therefore remove chlorine, pathogens, heavy metals and hydrocarbons from unfiltered tap water. Most water bottle filters retail for under $20.00 and some claim 99% efficiency in treating 80 gallons of water with a single filter insert:

In summary, there is a potential for toxic compounds (lead, trihalomethanes,volatile organic compounds, which the US Environmental Protection Agency regulates) and aesthetic contaminants (iron, sediment, chlorine) to reach NYC taps. All can be removed with greater than 99% efficiency using combination media/activated carbon filtering systems. The systems, including filter replacement, are relatively inexpensive. Filter inserts for water bottles are even less expensive, but are not designed to treat typical household water volumes and have slightly less pollutant removal efficiencies (99% vs. 99.99%.)