While this website is by a US-based consulting business and for US-audiences, it has a good definition of greywater (water that has been used in the home except for toilets), why use it, and how it is legally used in the US.  

Two-page summary sheets with illustrations.

This report documents the results of studies on open defecation in rural communities and the cultural values that reinforce its practise carried out by WaterAid in four West African countries — Burkina Faso, Ghana, Mali, and Nigeria.

This book provides in-depth technical information about the design, construction, operation and maintenance of the major types of on-site sanitation facility, from simple pit latrines to aqua privies and septic tanks. Recognizing that the introduction of on-site sanitation system) involves considerably more than the application of simple, engineering techniques, the authors describe in detail the planning and development processes, and the financial and institutional factors that will need to be taken into account.