From Water Wiki

Faucets 15.7%

of Household Water Use

Faucet water use is the fourth highest indoor water use at 15.7%. This includes all faucet use throughout the house and in total averages about 10.9 gallons a day. Reducing faucet use time is an easy way to save water. Washing dishes or pre-rinsing before using the dish washer can significantly increase faucet water use, so using your dishwasher without pre-rinsing is a good first step to saving water (h2ouse.org).

Faucet water use rates 
                                                                    National Average*
Daily Per Capita Use                                         10.9 gallons
Avg. Faucet Flow Rate                               1.3 gallons per minute
Daily Per Capita Faucet Use Duration                 8.1 minutes
(h2ouse)

Saving water from faucet use is a relatively easy fix; simply installing low-flow faucet aerators can cut faucet water use by 13-75%. Low-flow faucet aerators can be found at your local hardware store and run from 1.50-10$ (eartheasy). Many faucets already have aerators rated at 2.75 gpm. This is easily found written on the side of the faucet aerator itself, the piece of the faucet right at the end where the water comes out. If your faucet has no aerator or has an aerator rated over 2.75 gpm, installing a low-flow faucet aerator will greatly decrease your faucet water use (metaefficient).

Low-flow faucet aerators run from .5 to 2.75gpm. While the change in water flow can be noticeable when installing some ultra low-flow aerators (.5-1.5gpm) there still is enough water output for all your faucet uses. The decrease in water flow may take some time to get used to but installing an ultra low-flow aerator cuts water use drastically.

Faucet water use in homes in standard and conserving homes                                     
                                            Typical Faucet Flow Rates (gal. per minute)                                  Avg. Faucet Gallons per Person Per Day                                Avg. Minutes of Faucet Use per Person Per Day
Non-conserving Home                                       2.75                                                                                          23.1                                                                                            8.4
Conserving home                                               .5                                                                                          4.45-7.5                                                                                       8.9-15
(h2ouse)

As we can see above even though minutes of use may increase, the water savings is still significant. Installing faucet aerators is a cheap and easy way to decrease household indoor water use.

Sources:
http://www.metaefficient.com/bathroom-products/the-most-efficient-faucet-aerators-of-2008.html
http://www.eartheasy.com/live_lowflow_aerators.htm
www.conservastore.com