After being cleared to taxi to the ramp via Taxiway G; the flight crew of a C560 realized the DWH airport gate containing a gross weight restriction note that precluded their use of the taxiway. Later discovered an airport sign which stated the weight limit was much higher.

Narrative

Upon landing on Runway 17R at DWH; Tower stated to either execute a 180 on the runway and to take Taxiway E and taxi to the FBO or to turn right on Taxiway G and taxi to the FBO. The landing roll out brought the aircraft at a closer distance to turn at G than to make the 180 on the runway back to E. After being established on Taxiway G and noticing unusual landscape (cow pastures and woods on both sides) the PIC referenced the airport diagram again and noticed a weight restriction for that particular taxiway. At that point we were not in a position to turn around and exit Taxiway G. Our only option was to continue to the FBO via Taxiway G. Under certain circumstances our aircraft would be under this particular weight restriction. However; this particular flight we recognized that we were in fact over the weight restriction of the taxiway. This is both mine and the SIC's first time flying into DWH. At no time did we feel the safety of the aircraft was in question while on this taxiway. One way to avoid this mistake again is to make a conscious effort to brief more thoroughly all of the notes on the airport page including the airport diagram. On the taxi out leaving DWH; a sign for Taxiway G south of E indicated that the max weight is 25000 lbs while the airport page says 12499 lbs. We noticed many aircraft that were larger than us utilize Taxiway G south of E while we were preparing to depart the next day. The airport diagram and the airport signage tend to disagree and perhaps could be reviewed to reflect the same and proper information.