Pump Duty Workbench
Open the workbench

Size the pump, check the main, before the first coffee goes cold.

A browser-based duty calculator for UK water and wastewater pumping stations. Enter the levels, the rising main and the manufacturer's curve. Get the duty point, power, NPSH, surge and wet well checks in one live sheet.

Start a calculationSee pricing

Built for how pumping station calcs actually get done

Duty at both levels

System curves at start and stop levels, parallel pumps, VSD speed through the affinity laws, and the one-pump-running case.

Losses you can audit

Darcy–Weisbach with Colebrook–White, editable K values for every fitting, and a breakdown table a checker can follow line by line.

Calc summary in one click

Copy a plain-text summary with the design basis, criteria and every check, ready for a calc sheet or an email to the checker.

Over twenty design checks, live as you type

Answer five setup questions and only the inputs your job needs are shown. Typos such as a diameter in metres or a reversed pump curve are caught before they reach the results.

  • Duty flow at BWL against requirement
  • Self-cleansing and maximum main velocity
  • Pump branch velocity
  • Joukowsky surge upper bound against PN
  • Downsurge and column separation risk
  • Summit above discharge level
  • Preferred operating range against BEP
  • Motor rating and non-overloading power
  • NPSH margin at BWL
  • Solids passage
  • One pump running
  • Pump curve fit quality
  • Wet well volume for starts per hour
  • Rising main retention and septicity
  • Level order and pump submergence
  • Duty beyond the published curve
  • Minimum pump run time
  • Emergency storage per dwelling or hours at DWF
  • Rising main minimum bore
  • Surge study trigger length
  • VSD speed range and drive minimum speed
  • Run-out NPSH with one pump tripped

Criteria are editable. Pro adds criteria taken from published guidance: the IWNL Adoptable Pumping Station Design Guide, Anglian Water's and Yorkshire Water's local practice for pumping stations. Always confirm against the current client specification before issue.

Pricing

Free

£0

Duty point at both levels, pump and system curves, station section, and every hydraulic, pump and station check against typical UK criteria.

Open the workbench

Pro, annual

£99/year + VAT

Everything in Free, plus Excel calc sheet export with title block and design basis, IWNL, Anglian Water and Yorkshire Water design criteria, and the one-click calc summary.

Subscribe annually

Pro, monthly

£12/month + VAT

The same Pro features, billed monthly. Cancel any time; Pro stays on until the end of the paid month.

Subscribe monthly

Prices are before VAT; UK VAT is added at checkout for customers without a VAT number. Gumroad shows the charge in US dollars at the current exchange rate. Payments are handled by Gumroad. Cancel any time from your Gumroad library or the link in your receipt.