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Water network and connection pipe diameter selection

Flow m3/h

Flow dm3/s

Pipe series

Length [m]

Velocity crit. [m/s]

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Water service connection and network calculator — PE pipe sizing

Professional calculator for sizing PE (polyethylene) pipes in water service connections and distribution networks. Based on the entered design flow, section length and velocity criterion, the calculator selects PE100 pipe diameters (SDR17 PN10 and SDR11 PN16) and determines the total pressure drop along the section. A tool designed for water network designers, installers and water utility companies.

How to use the calculator in 3 steps

Enter the design flow rate in m³/h or dm³/s — the calculator automatically converts between units. Determine the design flow beforehand based on the sum of normative outflows of sanitary fixtures (per PN-92/B-01706) or from the network balance.

Set the connection or network section length [m] and the velocity criterion [m/s]. The default criterion is 1.5 m/s — suitable for service connections. For distribution networks, 1.0 m/s is recommended.

Read the results: for both PE pipe series (PN10 and PN16), the calculator displays a list of diameters with actual flow velocity [m/s] and total pressure drop [kPa] along the section. Select the diameter that meets the velocity criterion.

PE100 pipes in water supply networks

PE100 (third-generation high-density polyethylene) pipes are the most commonly used material in water networks and service connections. The PE100 designation indicates a minimum required strength MRS = 10 MPa, allowing operation at higher pressures than older PE80 pipes (MRS = 8 MPa).

PE100 SDR17 (PN10) — the ratio of outer diameter to wall thickness is 17. Nominal pressure 10 bar (1.0 MPa). The most popular series for water networks and residential service connections, where operating pressure rarely exceeds 6 bar.

PE100 SDR11 (PN16) — thicker wall, nominal pressure 16 bar (1.6 MPa). Used where higher operating pressure is required, e.g., in municipal networks with large elevation differences or in industrial applications.

PE pipes are joined by butt fusion welding (from DN 63) or electrofusion (from DN 20). Both joints are as strong as the pipe itself. Unlike steel pipes, PE pipes are corrosion-resistant and do not require cathodic protection.

Recommended design values for networks and connections

Key design parameters for PE pipe sizing in water supply networks:

Velocity in service connections: up to 1.5 m/s (PN-92/B-01706) — higher velocities cause excessive noise and pressure losses. In practice, optimal velocity is 0.8–1.2 m/s.
Velocity in distribution networks: up to 1.0 m/s (PN-92/B-01706) — longer sections require lower velocities to limit pressure losses.
Total pressure drop on a service connection should not exceed 20–30 kPa (0.2–0.3 bar). For longer connections (over 30 m), consider increasing the diameter by one size.
Minimum service connection diameter: DN 40 (PE 50 x 4.6 SDR11 or PE 50 x 3.0 SDR17) for single-family buildings. For multi-family buildings: from DN 63.
Water service connections are laid at a minimum depth of 1.4–1.6 m (below the frost line) with a slope of 0.3–0.5% towards the water main.