Professional breeders of Portuguese Water Dogs. You will find that most PWD breeders have small, family operations.
Before buying a puppy, make every effort to see the puppy's parents, and to ensure that the breeder is reputable and is careful to breed only those dogs with no serious conformation defects or genetic problems.
Sites for anyone breeding and selling PWDs belong in this category. Sites about pet PWDs, even though they may have a "kennel name", belong in the PWD/Pets category.