Selecting the right dewatering pump for a construction site requires three assessments:
1. Calculate drainage volume (LPM required)
Estimate peak inflow from all sources: rainfall runoff, groundwater seepage, and any water used in construction. A standard rule for open excavations in India’s monsoon belt is 2–5 LPM per 100 m² of exposed soil. Multiply by total exposed area. Add 30% safety margin.
2. Determine total head (metres)
Total head = vertical lift (depth of excavation) + pipe friction losses (approximately 10% of pipe length). For most urban construction pits (3–8 m deep), this gives a total head of 12–25 M — well within the CDW Standard range.
3. Match product to conditions:
| Condition | Recommended Pump |
|---|---|
| Clean to dirty groundwater, solids ≤12 mm | Cosmos CDW (1.5–50 HP, up to 86.5 M head) |
| Thick mud, dense sludge, solids up to 70 mm | Cosmos CNC Non-Clog (6–20 HP, 22–30 M head) |
| No electricity, portable/multi-site use | Cosmos CAP Auto-Prime (diesel, trolley/canopy) |
| Large open cut, high volume (>10,000 LPM) | Cosmos CAP (up to 74,483 LPM) |
For precise pump selection on your project, contact the Cosmos engineering team with your excavation dimensions and water inflow data.
