WDrainage
WLago di Bientina
WDitch
WDrain cover
WDrainage equation
WDrainage law
WDry well
WEnDrain
WFrench drain
WGargoyle
WGrating
WInfiltration basin
WInvert level
WPranala
WRunoff model (reservoir)
WSahysMod
WSaltMod
WScoop wheel
WSewer dosing unit
WSlot drain
WStorm drain
WStormwater
WSustainable drainage system
WTree box filter
WTwo-stage drainage ditch
WWater table (architecture)
WWeeping tile