Sump Pump Calculator

Basement & car-park dewatering · Dubai

Sump Pump Sizing

Wet-well volume, pump duty, discharge line and cycle-time check against Dubai Municipality guidelines and international plumbing-code baselines.

1Catchment & design storm

Sets the design storm return period per Dubai Municipality Stormwater Design Guidelines. Underground car parks are checked against the 1-in-100-yr event.
Storm duration used to read rainfall intensity off the Dubai IDF curve — typically 10–20 min for a compact ramp/car-park catchment.

1Sewage inflow

From your fixture-unit / Hunter’s-curve drainage calculation for the connected foul-water fixtures.
Used only to flag the duplex-ejector trigger point common to UPC/IPC-family codes (typically 3–6 WCs, threshold varies by jurisdiction).

2Pump configuration

Used to estimate motor duty (P = ρgQH/η), which sets the minimum inter-start cycle time from the DM motor-size table below.

3Wet well / pit

IPC-family baseline sets a 450 mm (18″) minimum pit diameter. Increase this if the required active depth falls outside the 200–500 mm float-spacing band.

Basis of design

Every figure above is traceable to one of the sources below. Numbers marked DM come from current, published Dubai Municipality design guidelines; Intl. marks widely-used international plumbing-code / industry baselines used to fill gaps the Dubai guidelines leave open.

Dubai IDF table (Dubai Municipality Stormwater Design Guidelines V2, Table 0-2) rainfall intensity, mm/hr

Interpolated log-linearly between tabulated durations for any time-of-concentration not listed directly.

Why DEWA doesn’t appear in the calculations

DEWA regulates electricity and water connections in Dubai, and its published Green Building Regulations cover greywater reuse and discharge-quality rules — but no publicly indexed DEWA document sets sump-pit or sump-pump sizing criteria. The Dubai authority that actually publishes those criteria is Dubai Municipality (Sewerage Design Guidelines and Stormwater Design Guidelines, both dated 2025), so this tool cites DM directly rather than attributing sizing rules to DEWA. Confirm any DEWA-side approval or power-supply requirements for the pump room separately.

Formulas & code clauses used
  • DMWet-well storage: V = t·Q / 4 — DM Sewerage Design Guidelines §5.1.4 (24.01.25). Also documented internationally in US UFC EI 11C201 and standard lift-station design practice.
  • DMMinimum inter-start cycle time by motor size — 0.75–30 kW: 10 min · 35–60 kW: 15 min · 65–300 kW: 20 min · >300 kW: 30 min (consult manufacturer). DM Sewerage Design Guidelines §5.1.4.
  • DMFloat / start-stop level spacing: 200–500 mm. DM Sewerage Design Guidelines §5.1.4.
  • DMDuty/standby: 2 pumps at 100% each (1 standby) or 3 pumps at 50% each (2 duty + 1 standby). DM Sewerage Design Guidelines §5.1.5.
  • DMRising-main velocity: 1.0–2.5 m/s. DM Stormwater Design Guidelines V2 §6.7.
  • DMDesign storm return period by facility type, incl. 1-in-50-yr (checked to 1-in-100-yr) for underground car parks/underpasses. DM Stormwater Design Guidelines V2 §4.1.1.
  • Intl.Rational Method: Q = C·i·A / 360 (Q in m³/s, i in mm/hr, A in hectares) — standard international peak-runoff estimate.
  • Intl.Minimum pit size 450×600 mm (18″×24″ dia. × depth) and solids passage (50 mm where a WC is connected, else 25 mm) — IPC-family baseline (verified via NYC & Philadelphia plumbing codes, which adopt IPC §712 near-verbatim; some jurisdictions amend the depth upward, e.g. Chicago to 30″).
  • Intl.Duplex-ejector trigger at fixture-unit / WC-count thresholds — reported as 3 WCs (Minnesota, UPC-derived) up to 6 WCs (Chicago, IPC-derived); treated here as “typically 3–6”, with duplex used as this tool’s default regardless.
  • GapPit freeboard and bottom (suction) clearance: no explicit figure found in DM guidelines. This tool applies 300 mm + 300 mm as general engineering practice — confirm against the selected pump manufacturer’s submergence requirement.
Sources

Dubai Municipality, Sewerage Design Guidelines (24.01.25).
Dubai Municipality, Stormwater Design Guidelines V2.
DEWA, Green Building Regulations & Specifications (drainage/discharge quality only — no sump sizing content).
NYC Plumbing Code §712.3.2 and Chicago Plumbing Code §18-29-712 (IPC-family sump/ejector baseline).
Minnesota Rule 4715.2440 (UPC-derived duplex threshold, residential minimum storage).
US Unified Facilities Criteria EI 11C201, Table 7-1 (minimum pump cycle times, corroborating basis for V = tQ/4).

Preliminary sizing aid, not a stamped design. This tool estimates orders of magnitude from published Dubai Municipality guidelines and common international plumbing-code practice. It does not replace a licensed MEP engineer’s detailed hydraulic calculation, pump manufacturer’s selection, or Dubai Municipality / DEWA / civil-defence approval — confirm final pit dimensions, pump curves and electrical duty against the selected equipment and the authority’s current review comments.
Dubai IDF data: DM Stormwater Design Guidelines V2, Table 0-2 · Cycle-time & duty/standby rules: DM Sewerage Design Guidelines §5.1.4–5.1.5