the oecd principles on water governance rather than providing a general toolkit unfit for most situations deliver and widely diffuse recommendations to policy makers to consider when reviewing existing policies or defining new ones table moreover rules are not necessarily embedded in laws in many countries they are rooted in customary water rights however there is an institutional layer mesoinstitutions which is often either neglected or even missing and that links the macroinstitutional layer at which rules are defined and the microinstitutional layer at which implementation takes place