A submersible pump is a motor-pump unit sealed inside a waterproof housing, designed to operate fully submerged in the liquid being pumped — eliminating suction lift requirements, priming steps, and above-ground pipework to the unit. Our submersible range covers five series — CDW, CNC, CSW, CSL, and CSL-TV — spanning 1.5 HP to 200 HP and handling every liquid from clean construction runoff through to 70%-solids slurry at a specific gravity of 2.1.
The primary selection driver is liquid type: solids size and specific gravity determine which series fits your application, while duty flow rate and total dynamic head determine the HP rating and sub-variant within that series. For surface-mounted alternatives up to 1,550+ HP, see our CAP Auto-Prime pump range or the CSP Self-Priming surface pump.
Key Takeaways
- Five submersible series: CDW (dewatering), CNC (non-clog drainage), CSW (sewage), CSL and CSL-TV (slurry) — 1.5 HP to 200 HP
- Liquid type (solids size + specific gravity) is the primary series selector; use CDW for up to 12 mm solids and SG 1.1, CSL for up to 70 mm solids and SG 2.1
- CDW comes in three head variants: Standard (up to 86.5 M), High Head (up to 140 M), Ultra High Head (up to 200 M)
- CSW handles municipal sewage at SG 1.7 with solids up to 100 mm; CSL uses 27% hi-chrome white cast iron for highly abrasive slurries
Which Submersible Pump Do You Need?
Use the five-series matrix below to match your liquid characteristics to the correct pump series. Once the series is confirmed, the HP and sub-variant are selected from flow rate and total dynamic head as described in the 3-Step Selection Guide below.
| Selection Criteria | CDW
Dewatering | CNC
Non-Clog | CSW
Sewage | CSL
Slurry | CSL-TV
Slurry Twin-Volute |
|---|
| Max solids size | 4–12 mm | Up to 70 mm | 20–100 mm | Up to 70 mm by wt. | Semi-solid / fibrous |
| Specific gravity (SG) | Up to 1.1 | Up to 1.2 | Up to 1.7 | Up to 2.1 | Variable |
| HP range | 1.5–120 HP | 6–20 HP | 2–200 HP | Up to 100 HP | Up to 100 HP |
| Impeller type | Vortex / enclosed | Vortex / channel | Channel / vortex | Hi-chrome WCI | Twin-volute hi-chrome |
| Typical applications | Construction dewatering, tunnels, mines | Sludge drainage, manhole cleaning, sewage bypass | Municipal sewage, STP, residential complexes | Ash transfer, slurry sumps, harbour construction | Mine tailings, abrasive sump duty |
| Motor insulation | Class H (180°C) | Class H (180°C) | Class F (155°C) | Class H (180°C) | Class H (180°C) |
| View full range | CDW Series → | CNC Series → | CSW Series → | CSL Series → | CSL-TV → |
Not sure which series applies to your site conditions? Use the iDEWA AI Pump Selector for an instant engineering recommendation.
Get Series Recommendation from iDEWACDW Submersible Dewatering Pump Range
The CDW Series is our core submersible dewatering pump line, engineered for construction sites, tunnels, mines, and infrastructure projects handling dirty or muddy water with suspended solids up to 12 mm and specific gravity up to 1.1. The range spans 1.5 HP to 120 HP across three head variants — Standard, High Head, and Ultra High Head — making it the most versatile dewatering series in the portfolio.
CDW Standard — 1.5 HP to 50 HP
The CDW Standard is the highest-volume site dewatering pump, handling flows from 450 LPM to 8,500 LPM at shut-off heads up to 86.5 M. Built with an aluminium alloy stator casing for superior heat dissipation over cast iron, Class H insulation rated to 180°C, and twin stainless steel mechanical seals (TC vs TC), the CDW Standard is designed for continuous duty in abrasive, muddy water without surface drying. An adjustable wear plate gap (±5 mm at site, no disassembly required) maintains hydraulic efficiency across the pump's service life.
Key features: 15 m waterproof PVC power cable · SS-304 hardware and strainer · Nitride-hardened SS-410 impellers (HRC 52–55) · Sacrificial zinc anode option for saline or seawater applications · Lightweight modular design with Al alloy top bracket. Available in SS-316 wetted-parts variant for coastal and marine deployments.
CDW High Head — 5 HP to 75 HP
Where standard head is insufficient — deep tunnels, underground mines, multi-stage hydro projects, and high-rise construction sumps — the CDW High Head variant extends shut-off head to 140 M with flow rates from 350 LPM to 2,200 LPM. HP range 5–75 HP covers mid- to large-scale drainage duties at elevated discharge pressures. The same Class H insulation, twin TC/TC mechanical seal, and aluminium alloy casing apply, with upgraded impeller stage geometry tuned for high-head performance.
CDW Ultra High Head — 50 HP to 120 HP
The CDW Ultra High Head variant addresses the most demanding underground dewatering requirements: shut-off heads up to 200 M, flow rates up to 200 m³/h, and HP ratings from 50 to 120. A 2-stage SS-316 impeller, CI FG300 motor body, dual SiC vs SiC mechanical seal with oil seal, Viton rubber parts for saline and high-abrasive tolerance, and an SS-431 high-torsional-strength shaft deliver the hydraulic robustness required for deep mine, hydro power, and major tunneling projects. The motor incorporates a thermal sensor and a naturally cooled design that operates effectively in submerged or partially submerged conditions.
| CDW Variant | HP Range | Flow Rate | Max Shut-Off Head | Best For |
|---|
| CDW Standard | 1.5–50 HP | 450–8,500 LPM | 86.5 M | Construction sites, highways, basements |
| CDW High Head | 5–75 HP | 350–2,200 LPM | 140 M | Deep tunnels, mines, hydro power plants |
| CDW Ultra High Head | 50–120 HP | Up to 200 m³/h | 200 M | Major tunneling, deep mine drainage |
All CDW variants handle dirty/muddy water with solids up to 12 mm and SG up to 1.1, pH 5–8. For slurry above SG 1.1 or solids above 12 mm, move to the CSL Series. For higher surface-pump capacity up to 1,550+ HP, see the CAP Auto-Prime range.
CNC Non-Clog Submersible Pump
The CNC Series is a compact, bottom-discharge non-clog submersible pump built to handle thick sludge, viscous mixes, and fibrous solids up to 70 mm in diameter — the category of liquid that blocks standard dewatering impellers within minutes. With a specific gravity rating up to 1.2, the CNC covers drainage applications where the liquid is heavier than clean water but not yet at true slurry densities: construction site sump desilting, manhole and stormwater pit cleaning, sewage bypass during STP maintenance, and trench drainage in clay-heavy soils.
The CNC's bottom-discharge configuration is critical for handling 70 mm solids — standard top-discharge submersibles cannot pass this particle size without clogging. The 14-inch compact body diameter fits directly into standard 14" manholes, making it the default choice for municipal contractors and EPC teams performing sewer bypass and stormwater rehabilitation.
Specifications: 6–20 HP · Flow rate 1,250–1,500 LPM · Shut-off head 22–30 M · 50 sq mm H07RNF heavy-duty cable (10 m) · SS-304 volute · Nitride-hardened SS-410 impellers (HRC 52–55) · Twin SS mechanical seals · Class H insulation (180°C) · Aluminium alloy lightweight design · Sacrificial zinc anode option for saline conditions.
For full technical specifications and discharge configurations, see the CNC Non-Clog Pump page.
CSW Sewage Submersible Pump
The CSW Series is our high-capacity sewage submersible pump range, designed for municipal corporations, residential complexes, and industrial sewage networks handling liquid at specific gravity up to 1.7 with solids up to 100 mm. Spanning 2 HP to 200 HP and flow rates from 775 LPM to 33,000 LPM, the CSW covers the complete range from single-building sump applications through to main city sewage lift stations.
Municipal sewage imposes conditions that general-purpose dewatering pumps are not rated for: high SG liquids loaded with rag, fibrous material, and solids up to 100 mm that cause wrap-around and clogging in standard impeller designs. The CSW uses a channel or vortex impeller configuration optimised to pass these solids without hydraulic bridging, paired with F-class insulation (155°C) with a thermal sensor, dual TC vs TC mechanical seal and oil seal, and an SS-410 high-torsional-strength shaft that withstands shock loads from large solid impacts.
Key technical features: SS-316 lifting hook · Angular/radial/tapper ball bearings with high-temperature grease · Optional Class H insulation upgrade · Optional moisture and temperature sensor for remote monitoring. The CSW integrates directly with CosmoSmart™ IoT monitoring for remote running-data access, alarm management, and service scheduling.
For flow curves, auto-coupling options, and STP/ETP bypass configurations, see the CSW Sewage Pump page. For rental deployments during sewage rehabilitation, see our pump rental division.
CSL / CSL-TV Slurry Submersible Pump
The CSL Series is a dedicated submersible slurry pump engineered for the most abrasive pumping duties in the industrial and mining sectors: ash transfer at thermal power stations, silt and sand removal, coal runoff sump drainage, mine waste pumping, harbour and dredging construction, and any application where fluid solids content exceeds 70% by weight at specific gravities up to 2.1.
Standard pump components are destroyed by high-abrasion slurry in days. The CSL uses 27% hi-chrome white cast iron (WCI) construction for all wetted parts — a material with a surface hardness 4–5× greater than standard grey cast iron, rated specifically for abrasive mineral slurries. Flow rates range from 1,584 LPM to 5,834 LPM at shut-off heads of 27.5 M to 52.5 M, with HP ratings up to 100 HP.
CSL-TV — Twin-Volute Variant
The CSL-TV adds a twin-volute casing to the CSL hydraulic, which cancels the radial thrust force generated at off-BEP operating points. In continuous slurry duty — mine tailings sumps, flyash sluicing lines — radial thrust is the primary bearing-failure mechanism. The CSL-TV's twin-volute design extends bearing life significantly, reducing unplanned downtime on duty-critical slurry transfers where pump replacement mid-operation carries high project cost.
For full CSL and CSL-TV specifications including hi-chrome material certifications and slurry particle size compatibility charts, see the CSL Slurry Pump page.
Industrial Applications Matrix
The table below maps the six primary industrial sectors served by the submersible range to the recommended series, with the engineering rationale for each selection:
| Application Sector | Recommended Series | Engineering Rationale |
|---|
| Construction site dewatering | CDW Standard (1.5–50 HP) | Clean to muddy water, 12 mm solids, fast site setup; modular design repositions across sumps without crane |
| Mining & tunnel drainage | CDW High Head / Ultra High Head | High TDH requirements (40–200 M) for deep mine levels; CDW Ultra HH to 200 M for major tunneling contracts |
| Municipal sewage lifting | CSW (2–200 HP) | SG 1.7, 100 mm solids, continuous-duty rated; auto-coupling installation for permanent lift station mounting |
| Slurry, ash & mining process | CSL / CSL-TV | 27% hi-chrome WCI withstands SG 2.1 and high mineral abrasion; CSL-TV for duty-critical continuous operations |
| Non-clog drainage & bypass | CNC (6–20 HP) | 70 mm fibrous solids, bottom-discharge, 14" manhole-fit body; the standard for sewage bypass and stormwater pit desilting |
| Defence, border infrastructure & remote critical projects | CDW High Head | Compact sealed unit, no surface installation; reliable restart in power-restore cycles; sacrificial zinc anode for marine/high-humidity environments |
3-Step Submersible Pump Selection Guide
Follow these three steps to identify the correct submersible pump series, HP rating, and CDW sub-variant for any new application. For complex multi-pump systems or unusual liquid characteristics, use the iDEWA AI Advisor for an instant engineering-grade recommendation.
Step 1 — Identify Liquid Type: Solids Size and Specific Gravity
Measure or estimate the two critical liquid parameters:
- Solids size (mm): The largest solid particle the pump must pass. If solids exceed 70 mm, a surface pump or grinder pump is required — no submersible in this range exceeds 100 mm passage at CSW.
- Specific gravity (SG): The density of the liquid relative to water (water = 1.0). Clean construction drainage: SG 1.0–1.05. Silty/muddy drainage: 1.05–1.1. Thick sludge: 1.1–1.3. Sewage: 1.1–1.7. Slurry/mineral: 1.5–2.1.
Map your SG and solids to a series using this rule:
- SG ≤ 1.1, solids ≤ 12 mm → CDW
- SG ≤ 1.2, solids ≤ 70 mm → CNC
- SG ≤ 1.7, solids ≤ 100 mm → CSW
- SG ≤ 2.1, solids ≤ 70 mm by wt. → CSL / CSL-TV
Step 2 — Calculate Required HP Using Total Dynamic Head (TDH)
Once the series is selected, calculate the Total Dynamic Head (TDH) to determine HP and variant:
TDH (M) = (Hs + Hf + Hv) × 1.20
- Hs = Static head (M) — vertical distance from the water surface in the sump to the discharge outlet
- Hf = Friction losses in the discharge pipe (M) — typically 0.1–0.15 M per 10 M of pipe length at normal velocities
- Hv = Velocity head (M) — usually 0.5–1.5 M for standard hose velocities; often negligible at low flow rates
- 1.20 = 20% engineering safety factor for fouled conditions, transient head surges, and pump curve ageing
Once TDH is known, cross-reference with the required flow rate (LPM or m³/h) on the pump curve. For CDW, also use TDH to select the sub-variant: Standard (head ≤ 86.5 M), High Head (head 40–140 M), Ultra High Head (head 90–200 M).
Step 3 — Select HP Rating and Variant
Use the HP quick-reference table below. Select the row matching your confirmed series, then pick the HP rating whose duty-point flow (at your calculated TDH) meets or exceeds the required site flow rate. Always size to the duty point, not shut-off head — a pump operating at shut-off wastes energy and creates hydraulic heat.
| Series / Variant | HP Range | Max Flow Rate | Max Shut-Off Head | Liquid SG | Max Solids |
|---|
| CDW Standard | 1.5–50 HP | 8,500 LPM | 86.5 M | 1.1 | 12 mm |
| CDW High Head | 5–75 HP | 2,200 LPM | 140 M | 1.1 | 12 mm |
| CDW Ultra High Head | 50–120 HP | 200 m³/h | 200 M | 1.1 | 12 mm |
| CNC Non-Clog | 6–20 HP | 1,500 LPM | 30 M | 1.2 | 70 mm |
| CSW Sewage | 2–200 HP | 33,000 LPM | 60 M | 1.7 | 100 mm |
| CSL / CSL-TV Slurry | Up to 100 HP | 5,834 LPM | 52.5 M | 2.1 | 70 mm by wt. |
If your required flow rate or TDH falls outside the submersible envelope, consider the CAP Auto-Prime surface pump (up to 1,550+ HP, 74,483 LPM) or explore short-term rental options for peak-demand or monsoon-season dewatering.
AI-Powered Pump Selection — iDEWA
iDEWA is our AI dewatering solution consultant, trained on the full submersible product range and deployed across 5,000+ projects and installations worldwide. Enter your site conditions — liquid type, solids, SG, flow rate, head, and project duration — and iDEWA returns a specific series, HP, and variant recommendation with engineering rationale, typically in under 60 seconds.
iDEWA is available to EPC contractors, mining operators, municipal engineers, and project procurement teams at no cost. It integrates with our rental and EPEC teams for turnkey deployment when required.
Use iDEWA — Free AI Pump Selector
Frequently Asked Questions
What is a submersible pump?
A submersible pump is a centrifugal pump with a hermetically sealed motor, designed to operate while fully immersed in the liquid it is pumping. The sealed motor prevents water ingress, and the pump pushes fluid upward through a riser pipe or hose to the discharge point at the surface. Because the pump is submerged, it requires no priming, no foot valve, and no suction lift — the static head of the liquid above the pump inlet provides positive suction, eliminating vapour lock. Submersible pumps are used across construction, tunneling, mining, municipal, and industrial applications where the pump unit must be positioned at or below the liquid surface.
What is the difference between the CDW and CNC pump series?
The CDW is a dewatering pump rated for dirty or muddy water with solids up to 12 mm and SG up to 1.1 — it is the correct choice for construction site drainage, mine sump dewatering, tunnel drainage, and foundation excavation pits. The CNC is a non-clog pump with a bottom-discharge design and a vortex/channel impeller that passes solids up to 70 mm at SG up to 1.2 — it is the correct choice for thick sludge, fibrous slurry, manhole and stormwater pit cleaning, and sewage bypass pumping during STP/ETP maintenance. Using a CDW in a 70 mm solids application will result in rapid impeller clogging; using a CNC for clean construction drainage introduces unnecessary cost. Match the series to the liquid type, not the project type.
Submersible pump vs surface pump (auto-prime) — when to choose which?
A submersible pump must be positioned at or below the water surface and requires a constant electricity supply — it cannot run dry. A surface auto-prime pump is positioned above ground, requires suction lift (typically ≤8.5 M), can be engine-driven (suitable for sites with no grid power or intermittent supply), and can run dry without damage. Choose a submersible pump when the pump must be placed inside the sump, when multiple small sumps must be served simultaneously, or when the application involves sewage or slurry that cannot be lifted via suction. Choose the CAP Auto-Prime surface pump when suction lift is available, when a diesel engine is required, when portability across multiple site moves is needed, or when very high flow rates (above 8,500 LPM) are required from a single unit.
How deep can a submersible pump operate?
The operating depth of a submersible pump is limited by the motor cable length and the cable's pressure rating, not by the pump hydraulics. Standard CDW units ship with a 15 M waterproof PVC cable; the CDW Ultra High Head ships with a 20 M cable. These cable lengths cover the vast majority of construction sump and mine sump applications. For deployment at greater depths — deep shaft mining, hydro tunnels — extended cable options or in-sump electrical junction boxes with cable extensions are used. The maximum submersion depth is always specified per unit; confirm with the engineering team before deploying beyond the standard cable length.
Can a submersible pump handle slurry?
Standard submersible dewatering pumps (CDW series) are not rated for slurry: the grey cast iron and aluminium alloy wetted parts are rapidly abraded by high-mineral-content fluids above SG 1.1. For true slurry applications — mine tailings, ash transfer, silt removal, sand and gravel pumping — the CSL Slurry Series uses 27% hi-chrome white cast iron (WCI) construction throughout the wetted path, which has surface hardness 4–5× greater than standard grey cast iron. For transitional sludge and thick viscous mixes (SG up to 1.2, 70 mm solids), the CNC Non-Clog is the intermediate option. Deploying a CDW in a CSL application will result in early wear-part failure and high total cost of ownership.
What is the recommended maintenance interval for submersible pumps?
For standard construction dewatering duty (CDW series, clean to muddy water), inspect the mechanical seal, wear plate gap, and impeller clearance every 500 operating hours or at the end of each major project phase, whichever comes first. For non-clog (CNC) and sewage (CSW) applications handling fibrous and coarse solids, inspect every 250–350 hours due to higher wear rates on seals and impeller channels. For slurry duty (CSL), replace hi-chrome wear parts every 150–300 hours depending on particle hardness and SG — maintain a wear-part kit on site at all times. The CDW's adjustable wear plate gap (±5 mm) can restore hydraulic efficiency without removing the pump from service. For all series, motor winding insulation and cable integrity should be tested with a megger every 12 months or after any major submersion incident.
