National Watercolor Associations:

American Watercolor Society  www.americanwatercolorsociety.org/
National Watercolor Society  www.nationalwatercolorsociety.wildapricot.org/
Transparent Watercolor Society  www.watercolors.org/
The Canadian Society of Painters in Watercolor http://www.cspwc.com
Australian Watercolor Institute http://www.awi.com.au

California Watercolor Associations:

www.Californiawatercolor. com ( featuring 20th century American Artists & the California Style.
They span an era of art from the 1920s through today).