Water retention can refer to:

• Water retention (medicine), an abnormal accumulation of fluid in the circulatory system or within the tissues or cavities of the body
  • Edema, an abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body
  • Premenstrual water retention, a common phenomenon associated with the menstrual cycle
• Water retention curve, relationship between soil water content and water pressure head
• Water retention on mathematical surfaces, topographic surfaces with basins
• Soil water (retention), the capacity of soil to hold water not removed by runoff, drainage or evaporation
• Retention basin