Under normal conditions, the results of gridding is that every potential top location ____________________.

In sprinkler design, gridding is a technique used to determine the layout of sprinklers to ensure uniform coverage across a specific area. When gridding is conducted under normal conditions, the goal is to achieve efficient water distribution that meets the requirements of the landscape being irrigated.

The correct answer focuses on how each potential top location within the design can typically be supplied with water. By being supplied from two directions, the layout allows for overlapping coverage from adjacent sprinklers. This redundancy is critical because it ensures that if one sprinkler fails or is temporarily out of service, the surrounding sprinklers can still provide adequate coverage to the area. This approach maximizes efficiency in water distribution and helps prevent dry spots.

Other choices do not align with the principles of effective sprinkler system design. For instance, being supplied from exact north-south locators limits potential placements and does not consider practical site layouts. Similarly, supplying from four locations might be excessive for many applications and could complicate installation and maintenance. Lastly, stating that locations will not have valved piping overlooks the importance of valves in controlling water flow and ensuring that each area can be serviced independently as needed. Therefore, the understanding that potential top locations will generally be supplied from two directions reflects the fundamental practices of designing an efficient