When do I need a pumping station?

A pumping station is needed when the drainage cannot flow by gravity to the public sewer — typically when the sewer is higher than the building drainage, or when the building is a long distance away and sufficient gradient cannot be achieved. They are common for basement drainage, low-lying sites and rural properties.

How do I size a pump station chamber?

Chamber volume is based on inflow rate multiplied by retention time, with a safety factor. For domestic properties, a 4-minute retention time is typical. The chamber must hold enough sewage between pump start and stop cycles to avoid frequent pump cycling, which causes premature wear.

What is total dynamic head (TDH)?

Total dynamic head is the sum of static head (the vertical height the pump lifts water) plus friction head (energy lost to pipe friction). The pump must overcome TDH to deliver the required flow. Rising main bends add equivalent pipe length — typically 1.5m per bend for friction calculations.

Do I need twin pumps?

Sewers for Adoption (now Design and Construction Guidance) requires twin pumps for adoptable pump stations — one duty, one standby. For private domestic stations, a single pump is acceptable but twin pumps provide resilience. A non-return valve (NRV) is always required on each rising main.

What rising main velocity should I aim for?

The ideal rising main velocity is 0.7-1.2 m/s. Below 0.7 m/s, solids may settle in the pipe causing blockages. Above 1.5 m/s, friction losses become excessive and water hammer risk increases. Select the pipe diameter that gives a velocity within this range for your design flow.

TradeCalculator.co.uk

Pump Station Calculator — Chamber Size, Pump Duty & Rising Main

Calculate pumping station chamber volume, pump duty point, rising main diameter and total dynamic head for foul or surface water pump stations.

Inflow Rate

Peak flow entering the chamber

Static Head

Vertical lift from pump to discharge

Rising Main Length

Total length of rising main pipe

Rising Main Diameter

Pump Type

Price Per Station (optional)

Total installed cost estimate

How We Calculate This

This calculator sizes a drainage pumping station based on inflow rates, static head and rising main characteristics.

The formulae

Chamber Volume = (Inflow / 60) × Retention Time × Safety Factor

Friction Head = (Loss per 100m × Equivalent Length) / 100

Total Head = Static Head + Friction Head

Pump Power (kW) = (Flow × TDH × 9810) / (Efficiency × 1000)

Key parameters

Retention time: 4 minutes (domestic standard)
Pump efficiency: 60% assumed
Bend equivalent length: 1.5m per bend

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.