Saint Paul is often referred to as the city of seven hills. This topography requires that a substantial amount of water in the distribution system be re-pumped through the utility's booster stations to provide sufficient pressure in the high-lying areas.

The system is built on five elevation layers: low service, high service, boosted service, secondary boosted service, and reduced pressure service.

Within one elevation layer, there may be several distinct zones. For example, the Saint Anthony Park zone and the Highland Park zone are on the same elevation layer, but are distinctly separate zones. Each zone has a reservoir system for storage.

The low-service area embraces downtown, the low-lying regions south and southwest of downtown Saint Paul.

The high-service area encompasses the central portion of Saint Paul.

The boosted service consists of Saint Paul’s Highland Park, the Upper West Side, and much of the East Side, in addition to St. Anthony Park, Mendota Heights, and much of Maplewood.

Secondary boosted areas include West Saint Paul and the south and east portions of Maplewood.

The reduced pressure service areas are found on steep hillsides. As water flows downhill it can lead to dangerously high pressures at the bottom of the hill. This requires the placement of pressure reducing valves on the water mains that feed downhill in these areas. These areas include the West Side bluff and the south Lexington Avenue bluff.