Summary of 10 States Standards for Drinking Water Distribution Piping Design

by Erin Heydinger
April 6, 2017

The Great Lakes-Upper Mississippi River Board develops recommended standards for water works. These standards are followed by regulatory agencies in Minnesota and are used for the design of water systems.

Below is a summary of system design standards for distribution system piping and appurtenances:


  • The system should maintain a pressure of 20 psi at all points under all flow conditions.
  • Normal working pressure should be 60 to 80 psi, and no less than 35 psi.


  • Water mains that provide fire protection should be at least eight inches (8″) in diameter.
  • Water mains that do not provide fire protection should be at least three inches (3″) in diameter.

Fire protection:

  • Systems should be designed in accordance with State Insurance Office fire requirements.

Dead ends:

  • Dead ends should be minimized to reduce stagnant water, provide reliable service, and reduce head loss.
  • Dead ends should be equipped with a way to provide flushing at a rate of at least 2.5 feet per second in the pipe being flushed.

For the full set of the standards, click here.

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