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Pump Introductions
Sep. 01, 2026
Drawing water from a well becomes more challenging as the distance between the pump and the water level increases. A conventional surface pump may work well with a shallow water source, but deeper suction conditions require a different hydraulic solution.
The Stream SDP Shallow Well JET Pump is designed for exactly this type of application.
Unlike a conventional self-priming JET pump with an ejector integrated inside the pump body, the SDP system can use an external ejector installed down in the well and connected to the surface pump through two pipes. This configuration allows the system to reach significantly greater suction depths while keeping the electric motor and main centrifugal pump above ground.
The Stream SDP series includes the SDP255, SDP355 and SDP505, with motor power from 550 W to 1100 W, maximum flow from 35 to 60 L/min, maximum head from 45 to 60 m, and maximum suction depth from 15 to 30 m depending on model.
For households, farms and irrigation systems that need to draw clean water from a well while keeping the main pump accessible at the surface, the SDP provides a practical alternative between a conventional shallow-well JET pump and a fully submersible deep-well pump.
The Stream SDP is a cast iron JET pump system designed for well water supply, household use and irrigation.
Its most important characteristic is the ejector arrangement.
In a conventional surface JET pump, the ejector is normally integrated into the hydraulic body of the pump. This design is simple and compact, but suction depth is limited by the physical conditions affecting surface-mounted suction pumps.
The SDP provides a different solution. The ejector can be positioned down in the well and connected to the centrifugal pump body by two pipes.
One pipe participates in delivering pressurized water to the ejector, while the other carries the resulting water flow back toward the surface pump. By moving the ejector closer to the water source, the system can operate at greater well depths than a conventional single-pipe surface JET pump.
| Model | Power | Max. Flow | Max. Head | Max. Suction Depth |
|---|---|---|---|---|
| SDP255 | 550 W | 35 L/min | 45 m | 15 m |
| SDP355 | 750 W | 38 L/min | 50 m | 25 m |
| SDP505 | 1100 W | 60 L/min | 60 m | 30 m |
The values above are maximum ratings for the individual models. Maximum flow, maximum head and maximum suction depth do not occur simultaneously at the same operating point. Actual performance depends on the well depth, water level, pipe diameter, pipe length, hydraulic resistance and installation conditions.
At first glance, the SDP may look similar to a conventional cast iron JET pump. The major difference is found in the hydraulic system.
A conventional self-priming JET pump generally has its ejector installed inside or directly adjacent to the surface pump body. The complete pumping mechanism therefore remains above the water source.
This arrangement is convenient, but atmospheric pressure places a practical limit on how high water can be lifted by suction alone.
For this reason, conventional shallow-well surface JET pumps are commonly associated with water levels of approximately 8–9 meters or less under suitable conditions.
The Stream SDP overcomes this limitation by allowing the ejector to operate down inside the well.
Instead of requiring the surface pump to create the entire suction lift from above, the external ejector uses circulating water to help lift well water toward the surface.
This is why the SDP series can provide maximum suction depth ratings of 15 m, 25 m and up to 30 m depending on model.
Understanding the two-pipe ejector system is important when selecting an SDP pump.
The system consists of a surface-mounted centrifugal pump and an ejector positioned down in the well.
The two components are connected through two water pipes.
When the electric motor starts, the centrifugal pump generates water flow and pressure.
Part of this pressurized water is directed down one of the pipes toward the ejector.
Inside the ejector, water is accelerated through a nozzle.
The increased velocity creates a low-pressure region that helps draw additional well water into the ejector.
The water drawn from the well combines with the circulating drive water inside the ejector.
The combined flow is then directed upward through the second pipe toward the surface pump.
The centrifugal pump receives the returning water and supplies it to the household, pressure tank, irrigation system or other clean-water application.
Part of the water continues toward the point of use, while the amount required for ejector operation is recirculated through the system.
The main reason is simple: greater well depth.
A conventional surface pump cannot continuously pull water upward from unlimited depth. Atmospheric pressure establishes a fundamental physical limitation on suction lift.
By placing the ejector lower in the well, the SDP changes how the hydraulic system operates and allows water to be supplied from considerably deeper sources.
This makes an external-ejector JET system particularly useful when the water level is too deep for a normal shallow-well surface pump but the user still wants the electric motor and main pump to remain above ground.
The most distinctive performance characteristic of the Stream SDP series is its suction capability.
The SDP255 is rated for maximum suction depth up to 15 m, the SDP355 up to 25 m, and the SDP505 up to 30 m under the specified conditions.
This gives users three performance levels for different well depths and water requirements.
However, pump selection should never be based only on the physical depth of the well.
The important measurement is the relationship between the pump installation and the actual water level, together with the dynamic water level while pumping.
One of the most important considerations when choosing a well pump is understanding that the total depth of a well is not necessarily the same as the required pumping depth.
The static water level is the distance from the surface to the water when the pump is not operating.
The dynamic water level is the water level while the pump is running.
As water is removed from the well, the water level can fall. This change is commonly known as drawdown.
For pump selection, the dynamic operating condition is more important than simply knowing how deep the bottom of the well is.
A well may be 40 meters deep while its water level is much closer to the surface. Conversely, a pump selected too close to its maximum suction capability may struggle if the water level falls significantly during pumping.
The external ejector arrangement is the defining feature of the SDP system.
By installing the ejector down in the well, the system can access water sources beyond the normal suction range of many conventional surface JET pumps.
The SDP is supplied with the shallow-well JET ejector installed and is also supplied with components for deeper-well configurations.
This provides greater flexibility when adapting the pump to different well installations.
The SDP uses a cast iron pump body.
Cast iron remains a widely used material for conventional surface pumps because it provides a rigid and durable hydraulic housing for general clean-water applications.
The largest SDP505 model provides maximum flow up to 60 L/min, giving the series enough capacity for a range of household and irrigation water requirements.
In addition to deep suction capability, the SDP series provides maximum head up to 60 m depending on model.
This is important because a well pump must not only bring water to the surface; it may also need to provide useful pressure to a house, pressure vessel or irrigation system.
| Pump Body | Cast Iron |
| Motor Housing | Aluminum |
| Motor | Closed, Externally Ventilated |
| Impeller | Brass / PPO Optional |
| Insulation | Class B / F |
| Duty | Continuous Rated |
| Mechanical Seal | Steatite Ceramic / Metalized Carbon |
| Maximum Ambient Temperature | +40°C |
| Maximum Fluid Temperature | 80°C |
| Maximum Pressure | 10 bar |
Well water extraction is the primary application of the SDP.
Its external-ejector configuration makes it particularly useful where the water level exceeds the practical suction capability of a conventional single-pipe JET pump.
The SDP can supply clean well water for general household water systems.
When combined with appropriate pressure control equipment, it can form part of an automatic domestic water supply system.
The pump can be used with small and medium-sized pressure or surge tanks to create an automatic water distribution system.
A properly configured pressure tank system stores pressurized water and allows the pump to start and stop according to water demand.
The combination of well-water extraction, useful flow and relatively high delivery head makes the SDP suitable for garden irrigation and other clean-water watering applications.
Properties without a reliable municipal water network often depend on private wells.
A surface-mounted well pump system can provide a practical solution for homes, farms and other rural properties where clean groundwater is available.
| Feature | Stream SDP | Conventional JET Pump |
|---|---|---|
| Ejector Position | Can be installed down in the well | Usually integrated with surface pump |
| Pipe Arrangement | Two-pipe deep suction configuration | Typically simpler suction arrangement |
| Suction Capability | Up to 30 m depending on model | Best suited to shallower water levels |
| Surface Accessibility | Motor and main pump remain above ground | Motor and pump remain above ground |
| System Complexity | More complex ejector and piping arrangement | Simpler installation |
If the water level is relatively shallow, a conventional self-priming JET pump such as the Stream SJET series may provide a simpler solution.
When the water level is beyond the practical suction range of a standard surface JET pump, the SDP external-ejector system becomes more relevant.
For deeper wells, buyers may also consider a submersible pump.
The two solutions use fundamentally different approaches.
| Feature | SDP External-Ejector JET Pump | Submersible Well Pump |
|---|---|---|
| Motor Location | Above ground | Inside the well |
| Main Pump Accessibility | Easy surface access | Pump must normally be removed from well for service |
| Well Connection | External ejector and two-pipe system | Pump submerged directly in water |
| Typical Selection Reason | Keep motor and main pump above ground while reaching deeper water | Direct pumping from deeper wells |
The correct solution depends on well depth, bore diameter, water level, required flow, required pressure, installation preference and maintenance requirements.
One practical advantage of an external-ejector JET system is accessibility.
The ejector operates down in the well, but the electric motor and main centrifugal pump remain at the surface.
This allows routine inspection of the motor, pump body, mechanical seal and external connections without removing the complete pumping unit from the well.
For users and installers familiar with conventional surface pumps, this can make routine servicing more straightforward.
The Stream SDP installation requires appropriate control of the water column and protection of the suction opening.
A foot valve helps prevent water from draining back into the well when the pump stops, supporting reliable priming and restart.
A filter or strainer at the suction opening helps prevent larger debris from entering the ejector and hydraulic system.
Because the SDP is designed for clean water and chemically non-aggressive fluids, it should not be treated as a dirty-water or sewage pump.
The SDP255 uses a 550 W motor and provides maximum flow of 35 L/min, maximum head of 45 m and maximum suction depth of 15 m.
It is the entry model for applications where the water source is beyond the normal range of a basic surface JET pump but does not require the deeper capability of the larger SDP models.
The SDP355 increases motor power to 750 W, maximum flow to 38 L/min, maximum head to 50 m and maximum suction depth to 25 m.
It provides a middle option for domestic and irrigation installations requiring significantly greater suction depth.
The SDP505 is the largest model in the range, using an 1100 W motor.
It provides maximum flow up to 60 L/min, maximum head up to 60 m and maximum suction depth up to 30 m.
This makes it the strongest option in the SDP range for deeper water levels or applications requiring greater water delivery.
Do not select the pump only according to the total depth of the well.
Determine both static and dynamic water levels and allow sufficient performance margin for seasonal water-level changes.
The external ejector depends on correct water circulation between the surface pump and the ejector.
Pipe sizing and installation should follow the technical requirements for the selected SDP configuration.
Air entering the hydraulic system can interfere with priming and reduce pump performance.
All connections should therefore be correctly sealed.
A correctly installed foot valve helps maintain the water column, while the filter protects the suction opening and ejector from larger contaminants.
JET pump systems require proper initial filling and priming before operation.
Do not assume that self-priming or ejector operation means the pump should be started completely dry.
The SDP should be installed in a covered area and protected against unsuitable weather exposure while maintaining adequate motor ventilation.
Check initial priming, the foot valve, water level, pipe connections and the ejector installation.
Air leakage or incorrect two-pipe circulation can prevent the system from developing the hydraulic conditions required to lift water.
Actual flow decreases as the system must overcome greater suction depth and delivery head.
Long pipes, small pipe diameters, fittings and other restrictions can further reduce available flow.
Inspect the foot valve and pipe connections.
If water drains back toward the well after shutdown, the system may require priming again before normal operation can resume.
The well may have insufficient recovery rate for the selected pumping flow.
Pump selection should consider not only pump capacity but also how much water the well itself can sustainably provide.
The SDP is designed for clean-water pumping from wells, household water supply and irrigation applications.
Maximum suction depth depends on model: up to 15 m for SDP255, 25 m for SDP355 and 30 m for SDP505 under the specified operating conditions.
The SDP uses an external ejector that can be installed down in the well and connected to the surface centrifugal pump through two pipes. This differs from relying only on conventional surface suction.
No. The main electric motor and centrifugal pump remain above ground. The ejector is the component positioned down in the well for the deeper suction configuration.
The SDP505 provides maximum flow up to 60 L/min.
The SDP505 provides maximum head up to 60 m.
Yes. Irrigation is one of the specified applications of the SDP series.
Yes. Household water supply is one of its intended applications. The pump can also form part of an automatic water supply system when combined with appropriate pressure control equipment.
No. It is designed for clean water and chemically non-aggressive fluids.
The installation uses a foot valve and filter at the suction opening to help maintain the required hydraulic conditions and protect the system.
The pump should be installed in a covered area and protected against the weather.
For relatively shallow water sources, a conventional self-priming JET pump can provide a simpler installation. When the water level is beyond the normal suction range of a conventional surface JET pump, the SDP external-ejector system offers substantially greater suction capability.
That depends on well depth, bore diameter, water level, required flow and pressure, and installation preference. The SDP is particularly useful when deeper suction is required but keeping the motor and main pump accessible above ground is preferred.
The Stream SDP occupies an important position between a conventional shallow-well JET pump and a fully submersible deep-well pumping system.
Its key advantage is the external ejector arrangement. By placing the ejector down in the well and connecting it to the surface centrifugal pump through two pipes, the SDP can reach water levels that would be beyond the practical suction range of many standard surface pumps.
The three-model range provides maximum suction depths from 15 to 30 m, maximum flow from 35 to 60 L/min, maximum head from 45 to 60 m, and motor power from 550 to 1100 W.
Combined with rugged cast iron construction, above-ground motor accessibility and suitability for domestic water supply and irrigation, the SDP provides a practical well-water solution for homes, rural properties and other clean-water applications.
For users who want the accessibility of a surface pump but require significantly greater well depth than a conventional shallow-well JET pump can normally provide, the Stream SDP external-ejector JET pump offers a distinctive and proven hydraulic solution.
Address
No.17 XeDa Jimei Ind. Park, Xiqing Economic Development Area, Tianjin, China
Telephone
+86 13816508465
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