Engineering Design

What Are the Separation Distance Requirements for Underground Piping?

The separation distance for potable water and sewer pipelines located in the public right-of-way is governed by Arizona Administrative Code (AAC) R-18-5-502.C. The separation distance for reclaimed water pipelines located in the public right-of-way is governed by AAC R-18-9-602.F. The Maricopa Association of Government's "Uniform Standard Details for Public Works Construction (PDF)" standards 404-1, 404-2 and 404-3 detail the separation distance and protection requirements for the installation of potable water, reclaimed water and sewer pipelines for MAG participants.

The separation distance between potable water and sewer pipelines from other pipelines such as non-potable ground, surface, irrigation, storm, industrial, etc., pipelines located in the public right-of-way is not defined by the regulations or MAG standards. The MCESD recommends that these non-potable pipelines:
  • Be separated from potable water pipelines as specified by AAC R-18-5-502.C.
  • Be located no closer than two feet vertically nor six feet horizontally from all other pipelines unless the non-potable pipeline is encased in at least six inches of concrete or using mechanical joint ductile iron pipe at least 10 feet beyond any point on the pipeline.
For projects requiring an approval by the MCESD that involve pipelines located on or crossing private property, the Department will determine the separation distance requirements for these pipelines on a case-by-case basis.