Greywater is the wastewater from sinks, baths, showers (i.e., all domestic wastewater except toilet wastewater). With on-site sanitation systems greywater management is required (collection and disposal, or collection,  transport, treatment & reuse).

Greywater Management in Low- and Middle-income Countries (Sandec, 2006)

The use and disposal of greywater in the non-sewered areas of South Africa: Part 2 – Greywater management options (Water SA, 2007)

Understanding the Use and Disposal of Greywater in the Non-sewered Areas of South Africa (WRC, 2007)

Why things fail: greywater management in informal settlements, South Africa (eWISA, 2008)

Introduction to Greywater Management (EcoSanRes, 2005) [two-page introduction]

Introduction to Greywater Management (SEI, 2004)

Greywater Treatment Systems Assessment [in Kimberley, South Africa] (Linköping University,
2007)

Australia: Requirements for the Installation of Rainwater and Greywater Systems in Australia (National Water Commission, 2008)

Characterisation of Greywater from Peri-urban Areas in Nakuru, Kenya (MSc thesis, University of Applied Sciences, Weihenstephan, 2009)

See also:  Ecological Sanitation    Sanitation Practice

Websites
Greywater Information Central
Greywater Action
Greywater: what it is … how to treat it … how to use it

Reuse of greywater

Guidelines for the Safe Use of Wastewater, Excreta and Greywater - Volume 4: Excreta and Greywater Use in Agriculture − the 2006 WHO guidelines.

Greywater Use in The Middle East: Technical, Social, Economic and Policy Issues (IDRC, 2010)

What stops me from using greywater? (eWISA, 2006)

Greywater treatment and reuse (whole issue of Sustainable Sanitation Practice, October 2009)

A Scoping Study to Evaluate the Fitness-for-use of Greywater in Urban and Periurban Agriculture
(WRC SA, 2006)

Re-use of greywater for agricultural irrigation (eWISA, 2006) 

Greywater Use in Rural Schools: Guidance Manual (NEERI/UNICEF, India, 2007)

Microbiological assessment of food crops irrigated with domestic greywater (Water SA, 2006)

Graywater Reuse Project [2002−2004] (CBSE, Jordan) − very useful!

Growing gardens with greywater (excerpt from Chapter 3 of Growing Better Cities: Urban
Agriculture for Sustainable Development, IDRC, 2006)

Drip irrigation: The first drip system designed for greywater (ReWater, 2008)