C. Bailey wrote:
I just bought a house. The house is 3 years old. It has a stucco
exterior. For the last day, it has been raining with a strong wind

Masonry of all types is not impervious to water. Stucco should be
applied to a wall that has first been prepared by hanging a weather
barrier (felt or tyvek or equivalent) overlaid with wire lath before the
stucco is applied. Even so, the finished stucco is still slightly
permeable.

Paint and elastomeric coatings prevent penetration of water on masonry
surfaces. Many stucco homes are painted with latex acrylic paints, and
are therefore more waterproof. However, during last year's hurricane
season here in Florida it turned out that many newer homes with only one
or two layers of paint still leaked.

Some homes are built with synthetic stucco (dryvit) and moisture
penetration of this material is common.