Water Quality Awareness 101 26 | P a g e  Outlets that are too close to the tank floor and create a scour effect for settled sediments  Overflow pipe outlets that are not screened, allowing vermin/animals to enter tanks  Using materials that will degrade and adversely affect the drinking water quality, such as rotting timber, rusting metals and coatings peeling off Poorly positioned fixtures and design allows for unauthorised entry to site