As far as I can tell, you are not supposed to store any Geocoded data from Google into a database.  I have the same problem on a Drupal site.  The module I'm using stores latitude and longitude data in the database.  If you look at the terms of service referenced on the page jmort253 pointed to in his answer, you'll find this:
(from https://developers.google.com/maps/terms#section_10_1_3)
10.1.3 Restrictions against Data Export or Copying.
(a) No Unauthorized Copying, Modification, Creation of Derivative
  Works, or Display of the Content. You must not copy, translate,
  modify, or create a derivative work (including creating or
  contributing to a database) of, or publicly display any Content or any
  part thereof except as explicitly permitted under these Terms. For
  example, the following are prohibited: (i) creating server-side
  modification of map tiles; (ii) stitching multiple static map images
  together to display a map that is larger than permitted in the Maps
  APIs Documentation; (iii) creating mailing lists or telemarketing
  lists based on the Content; or (iv) exporting, writing, or saving the
  Content to a third party's location-based platform or service.
(b) No Pre-Fetching, Caching, or Storage of Content. You must not
  pre-fetch, cache, or store any Content, except that you may store: (i)
  limited amounts of Content for the purpose of improving the
  performance of your Maps API Implementation if you do so temporarily,
  securely, and in a manner that does not permit use of the Content
  outside of the Service; and (ii) any content identifier or key that
  the Maps APIs Documentation specifically permits you to store. For
  example, you must not use the Content to create an independent
  database of "places" or other local listings information.
(c) No Mass Downloads or Bulk Feeds of Content. You must not use the
  Service in a manner that gives you or any other person access to mass
  downloads or bulk feeds of any Content, including but not limited to
  numerical latitude or longitude coordinates, imagery, visible map
  data, or places data (including business listings). For example, you
  are not permitted to offer a batch geocoding service that uses Content
  contained in the Maps API(s).
Parts b and c really make it sound like what you and I are trying to do is a no-no.  Am I reading this wrong?