A method of determining a wade depth (dMax) in relation to a vehicle (1) when at least partially submerged in water. An attitude of the vehicle (1) is determined and a first height (dSensed) of the surface of the water measured relative to a first reference point on the vehicle (1). The wade depth (dMax) is determined based on the attitude of the vehicle (1) and said first height (dSensed). Alternatively, or in addition, the travel height (HS) of a vehicle suspension is determined. Aspects of the invention also relates to a system and a vehicle (1).