The code says that any window that is within 18" from the floor or 24" from the jamb of a door MUST be tempered. Additionally, if you were creating a bathtub "enclosure" then you would be required to provide tempered glazing. The Residential building code section R308.4 covers this issue. If your window meets one of these conditions then the contractor is right. If not, then you may want to follow his recommendation as a precaution. It is possible that an inspector may view the window as an "enclosure" for your tub however, I believe the intent of this code section is to regulate all glass enclosures.

the following is the code section:

R308.4 Hazardous locations. The following shall be considered
specific hazardous locations for the purposes of glazing:
1. Glazing in swinging doors except jalousies.
2. Glazing in fixed and sliding panels of sliding door
assemblies and panels in sliding and bifold closet door
assemblies.
3. Glazing in storm doors.
4. Glazing in all unframed swinging doors.
5. Glazing in doors and enclosures for hot tubs, whirlpools,
saunas, steam rooms, bathtubs and showers.
Glazing in any part of a building wall enclosing these
compartments where the bottom exposed edge of the
glazing is less than 60 inches (1524 mm) measured vertically
above any standing or walking surface.
6. Glazing, in an individual fixed or operable panel adjacent
to a door where the nearest vertical edge is within a
24-inch (610 mm) arc of the door in a closed position
and whose bottom edge is less than 60 inches (1524
mm) above the floor or walking surface.
7. Glazing in an individual fixed or operable panel, other
than those locations described in Items 5 and 6 above,
that meets all of the following conditions:
7.1. Exposed area of an individual pane larger than
9 square feet (0.836 m2).
7.2. Bottom edge less than 18 inches (457 mm)
above the floor.
7.3. Top edge more than 36 inches (914 mm)
above the floor.
7.4. One or more walking surfaces within 36
inches (914 mm) horizontally of the glazing.
8. All glazing in railings regardless of an area or height
above a walking surface. Included are structural baluster
panels and nonstructural infill panels.
9. Glazing in walls and fences enclosing indoor and outdoor
swimming pools, hot tubs and spas where the bottom
edge of the glazing is less than 60 inches (1524mm) above a walking surface and within 60 inches
(1524 mm) horizontally of the water’s edge. This shall
apply to single glazing and all panes in multiple glazing.
10. Glazing adjacent to stairways, landings and ramps
within 36 inches (914 mm) horizontally of a walking
surface when the exposed surface of the glass is less
than 60 inches (1524 mm) above the plane of the adjacent
walking surface.
11. Glazing adjacent to stairways within 60 inches (1524
mm) horizontally of the bottom tread of a stairway in
any direction when the exposed surface of the glass is
less than 60 inches (1524 mm) above the nose of the
tread.

HOPE THIS HELPS!!!

It sure does, thank you very much!