If you need to find altitude of an address, such as to check future house location to see if flood would be a problem, you can use Google Map.

Go to website: http://www.daftlogic.com/sandbox-google-maps-find-altitude.htm and type in your address. As shown in the picture below. White House (1600 Pennsylvania Ave NW, Washington, DC 20500) has elevation of 48 feet.

Find Altitude on Google Map