Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The basin in a dream is a servant or a maidservant. The water in it indicates wealth. Washing in it indicates marriage.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The basin indicates a woman. If it is of gold, she is a woman of ill repute. If of silver, she is a righteous woman.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The basin is interpreted as a servant. Whoever sees himself wash in it will be blessed with a servant.