A dewatering pump removes accumulated water from construction excavations, mine workings, flooded drainage channels, and below-grade structures — maintaining dry working conditions so operations can continue without interruption. Cosmos Pumps manufactures dewatering pumps from 1.5 HP to 1,550+ HP across three series: CDW submersible (1.5–120 HP), CAP auto-prime surface (up to 1,550+ HP), and CSP self-priming surface (up to 30 HP). The correct series depends on site depth, water type, solids content, and whether continuous grid power is available.
Dewatering pumps fall into three primary categories. The table below maps each type to its specifications and typical site application.
| Pump Type | HP Range | Max Head | Max Flow (LPM) | Key Application | Power Source |
|---|---|---|---|---|---|
| CDW Submersible | 1.5–120 HP | 200 m | 8,500 | Construction excavations, mines, tunnels — pump sits submerged in the water | Electric |
| CAP Auto-Prime Surface | Up to 1,550+ HP | 169 m | 74,483 | Flood control, large infrastructure, off-grid operations | Diesel / Electric |
| CSP Self-Priming Surface | Up to 30 HP | 28 m | 4,500 | Foundation dewatering, trenches, basements — surface-mounted | Electric |
Choose CDW when the pump must operate submerged. Choose CAP when suction head up to 9.8 m is available, the pump needs to move between sites, or diesel engine drive is needed for continuous off-grid operation. Choose CSP for medium-flow surface dewatering at sites with stable power.
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Sizing a dewatering pump to the site prevents two common failures: inadequate drawdown from an undersized pump, and wasted capital from an oversized one. These five steps produce a working specification.
The CDW series covers three sub-series designed for different head ranges and shaft depths. All three use aluminium alloy motor casings with Class H insulation (180°C), twin stainless steel TC/TC mechanical seals, nitride-hardened SS-410 impellers (HRC 52–55), and a 15 m waterproof PVC cable.
| Series | HP Range | Shut-Off Head | Max Flow | Solids Handling | Typical Application |
|---|---|---|---|---|---|
| CDW Standard | 1.5–50 HP | 15.5–86.5 m | 450–8,500 LPM | 4–12 mm, SG ≤ 1.1 | Construction excavations, basement dewatering, general site drainage |
| CDW High Head | 5–75 HP | 40–140 m | 350–2,200 LPM | 4–12 mm, SG ≤ 1.1 | Tunnels, mines, hydro power plants, deep infrastructure |
| CDW Ultra High Head | 50–120 HP | 90–200 m | 50–200 m³/h | 4–12 mm, SG ≤ 1.1 | Deep mines, metro tunnels, major civil infrastructure |
All CDW variants are available with a sacrificial zinc anode for saline water exposure and SS-316 wetted parts for aggressive liquid environments. For the full range of submersible dewatering pumps including CNC non-clog, CSW sewage, and CSL slurry series, see the submersible pump category.
Foundation excavations accumulate water that can halt operations within hours. CDW submersible pumps (1.5–50 HP) handle the fine grit and muddy water typical of construction pits — no foot valves or external priming required. For larger floor-plate excavations, multiple CDW units run from a single electrical distribution point. Cosmos operates a rental fleet of 500+ submersible dewatering pumps available on same-day deployment across Delhi NCR and within 48 hours across North India. Construction deployments run at 300+ per year.
Underground mines and open-cast quarries generate sustained water inflow that increases with depth. CDW High Head (5–75 HP, up to 140 m) and CDW Ultra High Head (50–120 HP, up to 200 m) sustain continuous operation at shaft depths where standard submersibles cannot develop the required head. Cosmos handles 50+ mining dewatering projects per year across coal, iron ore, and limestone workings. For mine water carrying slurry at SG above 1.1, CSL hi-chrome slurry pumps replace standard CDW — 27% hi-chrome impellers resist abrasive wear at SG up to 2.1.
Flood response requires pumps on site in hours. CAP auto-prime surface pumps (diesel-driven, 60–1,550+ HP) work without priming, handle 9.8 m suction lift, and pass debris-laden water through open impellers handling up to 75 mm solids. Cosmos deploys 80+ flood control pumps per monsoon season for municipal authorities and state disaster response units. CAP models are available through GeM (Government e-Marketplace) for pre-approved government procurement.
Cosmos Pumps Pvt. Ltd. manufactures dewatering pumps at a 95,000 sq. ft. vertical lean manufacturing facility in Faridabad, Haryana. Founded in 2013, the company has served 2,500+ customers across 5,000+ completed projects in 20+ countries.
Certifications:
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A dewatering pump moves groundwater or dirty water with small inorganic solids (up to 12 mm, SG up to 1.1) from excavations and drainage channels. A sewage pump moves wastewater containing larger organic solids (20–100 mm, SG up to 1.7) from septic systems, STP sumps, and drainage chambers. Cosmos CDW handles dewatering; Cosmos CSW handles sewage. Some sites need both — a CDW for groundwater control and a CSW for the sewage bypass.
Size by flow: required LPM = excavation volume (m³) ÷ target pump-out time (hours) × 16.67, plus 25% margin for ingress during pumping. A standard 300–600 m³ basement excavation with a 4-hour drawdown target needs 2,000–4,200 LPM — a 10–20 HP CDW Standard covers this range. For continuous tunnel dewatering or large excavations, HP alone does not determine the right pump; head and solids content matter equally. Contact Cosmos for site-specific sizing.
Yes. CDW pumps pass particles up to 12 mm at SG up to 1.1 — standard for construction site muddy water, mine seepage, and monsoon drainage. For coarser material up to 70 mm, specify CNC non-clog. For slurry with SG above 1.1, specify CSL hi-chrome slurry series. Specifying the wrong series for the solids content is the most common cause of early wear or blocked impellers on dewatering sites.
For shaft depths to 100 m and clean-to-turbid mine water: CDW High Head (5–75 HP, up to 140 m). For shafts beyond 100 m or head requirements above 140 m: CDW Ultra High Head (50–120 HP, up to 200 m). For mine water carrying abrasive slurry at SG above 1.1: CSL hi-chrome (SG up to 2.1). All three carry ISO 9001:2015 and CE certification for mine-site compliance documentation.