Trotec submerged water pumps of the TWP-E series
Trotec submerged water pumps of the TWP-E series
Trotec submerged water pumps of the TWP-E series
Trotec submerged water pumps of the TWP-E series
Trotec submerged water pumps of the TWP-E series
Trotec submerged water pumps of the TWP-E series
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Submerged pumps for clear water and waste water

We always have the best solution at hand: submerged clear water pumps and submerged waste water pumps

Submerged pumps: key facts in a nutshell

You would like to learn more about submerged pumps and need a quick overview? This page provides answers to the most important questions: What is a submerged pump? How do submerged pumps work? What purchase criteria should be taken into account before deciding for a model?

Functional principle of submerged pumps

Submerged pumps operate based on the principle of centrifugal force. The centrifugal force is the force acting to the outside in an orbital or spinning motion around a rotation axis. This principle is known from everyday life, for instance from laundry washing. During the spin cycle, the water in the washing machine is pressed to the outside and through the holes in the drum due to the fast rotation.

Submerged pumps take advantage of the same principle. First, the liquid is sucked in through an opening in the lower part of the device. A motor-driven impeller transports the liquid into the collector duct by means of centrifugal force. From there, the liquid is conveyed through a pressure outlet into the discharge hose and out of the pump.

The major advantage of submerged pumps as compared to other pumps is that they can be placed directly in the liquid. Draining operation does not require any pump lines leading to the liquid. The insulation of all live parts ensures operational safety. When used in one place only, high-quality submerged pumps can be left at the site of application permanently – there is no need to fear damage caused by wetness.

What is a submerged pump?

Submerged pump

Pumps are referred to as submerged pumps if they are submerged in the liquid (usually water) to be pumped off or recirculated during operation. These pumps are typically electrically operated. Depending on the volume to be conveyed, the pump performance can range from 600 to 30,000 litres per hour. The fields of application of submerged pumps are extremely diverse. The pumps are used both by the fire brigade and civil protection services, but also in the area of water supply, wastewater disposal, construction work, and even aquaristics.

Application in swimming pools
Application in a rain barrel
Application in manholes and drainage shafts
Perfect for draining ponds

Criteria for purchasing your submerged pump

Depending on where and how you want to use your submerged pump, you should prioritize different purchase criteria. The following criteria provide a good initial overview. Further information on the submerged pumps offered by Trotec can be found in the respective detailed descriptions.

  • Submersion depth: The submersion depth is the maximum permissible distance between the upper edge of the device and the water surface. It can be an important purchase criterion if the pump is intended to operate completely immersed in water. High-quality low-voltage pumps usually work to a submersion depth of seven metres.
  • Pump height: The pump height describes the difference in height between the place of draining and the target location higher up to which the liquid is transferred. A powerful clear water pump like Trotec's TWP 9005 E, for instance, offers a pump height of 11.5 metres, and a waste water pump such as Trotec's TWP 11025 E a pump height of 11 metres. If the target location is situated lower than the place where pumping takes place, the pump height is irrelevant since no pump performance is required in downslope direction.
  • Feed rate: The feed rate of submerged pumps is indicated in litres per hour. Entry-level models for private use often have a feed rate of only less than 1,000 litres. More powerful pumps are able to feed between 1,000 and 15,000 litres. With feed rates of more than 10,000 litres per hour, some submerged pumps can also be used when very high requirements have to be met, for example in case of flooding.
  • Particle size / grain size / solids size: The particle size (grain size or solids size) of submerged pumps indicates the maximum diameter of solids in the liquid to be pumped. Despite their name, clear water pumps can cope with particles sized up to 5 mm. Waste water pumps can be used for a considerably higher particle size of 25 mm.
  • Residual water level: The residual water level indicates how much water will be left on the ground or in the receptacle after pumping operation is completed. Submerged pumps with near-ground suction reach a residual water level of only a few millimetres. The remaining liquid can simply be wiped up. Near-ground suction is an important purchase criterion particularly when it comes to water damages inside buildings. High-quality models without this near-ground suction feature, such as Trotec's TWP 4025 E, leave a residual water level of around 35 mm. For applications like pumping water out of a well, however, such a residual water level is unproblematic.
  • Plastic or stainless steel: Submerged pumps with a pump housing made of stainless steel are more robust against the effects of weather, impacts and shocks. The resistant material also extends the service life of the pump. Stainless steel submerged pumps are therefore preferably used in wells or rainwater cisterns to pump water permanently. Plastic submerged pumps are mobile all-rounders with a comparatively low weight. They are easy and convenient to transport. In normal everyday use, a submerged pump with a high-quality plastic housing is sufficiently protected against impacts and external influences.
  • Float switch: The float switch ensures that the submerged pump switches on or off when a certain water level is reached. Submerged pumps with a lockable float switch are particularly practical as they allow for individual setting of the desired filling or water level. They can be used either in manual operation with automatic switch-on and switch-off or in continuous operation with fixed float switch.

Overview: Which of Trotec’s submerged pumps is best suited for which type of application?

Type of submerged pump: Submerged clear water pump Submerged waste water pumps
Fields of application TWP 4005 E / TWP 4006 E / TWP 7505 E / TWP 7506 E / TWP 9005 E TWP 4025 E / TWP 4036 E / TWP 7025 E / TWP 7536 E / TWP 9000 ES / TWP 11025 E / TWP 11000 ES
Clear, slightly contaminated water
Heavily contaminated water
Slightly chlorinated water
Washing machine leakage
Rain barrels
Pond / swimming pond
Water barrel
Small building pit

Brand quality plus cost-efficiency

Reliable, powerful and suited for the most varied fields of application: these are some of the quality features of Trotec's submerged pumps. Thanks to their high capacity they are able to withstand the most extreme conditions. HighPerformance in every respect – after all, we stand for brand quality and professional solutions with an excellent value-for-money ratio!

Our submerged pumps for clear and waste water are efficient, safe-to-operate "underwater" pumps that handle even high feed rates with ease. They can be used for versatile applications including irrigation and drainage in clean as well as in heavily contaminated water. Their range of applications includes, for instance, water removal from lakes, ponds and rivers, recirculation and suction of water from a pool, pond, cistern or rain barrel, and draining of a flooded basement.

For depending on whether it is used for clear or waste water, on shallow or deep surfaces, for small or large dirt particles, we recommend choosing a pumping solution that is optimally tailored to your requirements. While clear water pumps are suitable for use in swimming pools, tanks, cisterns and wells, submerged waste water pumps convey heavily contaminated water with particle sizes of up to 25 mm. For this reason, we decided to offer both submerged clear water pumps with near-ground suction and submerged waste water pumps.

The difference between submerged clear water and submerged waste water pumps:

Submerged clear water pumps:

Submerged clear water pumps are used to effectively pump off and recirculate clear liquids or liquids that are only slightly contaminated with dirt particles, for instance to convey domestic sewage, rain or seepage water, in case of a washing machine leakage or for draining a pool. The maximum particle size indicates how large the dirt particles may be without causing damage to the pump.

A particular advantage offered by submerged clear water pumps is the possibility of "near-ground suction". Due to this technical feature, the water can be pumped off to a particularly low water level of only a few millimetres – resulting in what is called "wipe-dry drainage". The minimum suction level to which water can be pumped off is specified in the pumps' technical data.

Particle size and residual water level by comparison
Particle size and residual water level by comparison
Particle size and residual water level by comparison

Clear water may only contain dirt particles up to a diameter of 5 mm. For a wipe-dry result, Trotec's submerged clear water pump with near-ground suction is able to pump water off to a residual water level of 3 mm when placed on level ground.

Submerged waste water pumps:

Submerged waste water pumps convey heavily contaminated water, which is for example required when emptying garden ponds, tanks or cisterns, pumping water out of building and waste water pits, withdrawing water from lakes, ponds and rivers, or in cases of emergency draining due to flooding. Here, too, the maximum particle size indicates the maximum diameter of the contaminations contained in the pumped liquid. Naturally, submerged waste water pump are also suited for transporting clear water. 

In addition to the already mentioned typical purposes of use, the versatile range of applications of submerged waste water pumps also includes drainage under difficult and extreme conditions. Due to their high-quality technology, the pumps are an indispensable aid for emptying building and waste water pits as well as for emergency draining in case of flooding.

Particle size and residual water level by comparison
Particle size and residual water level by comparison
Particle size and residual water level by comparison

Waste water may contain small stones, pieces of wood or clods of soil with a diameter of up to 25 mm. Trotec's high-performance submerged waste water pumps pump the water off to a residual water level of 35 mm.

A comparison of the delivery head and flow rate of our submersible pumps:

Delivery head and flow rate

Pump height and feed rate of the TWP 4005 E

Delivery head and flow rate

Delivery head and flow rate of the TWP 7505 E

Delivery head and flow rate

Delivery head and flow rate of the TWP 9005 E

Altura de entrega y caudal

Pump height and feed rate of the TWP 4025 E

Delivery head and flow rate

Pump height and feed rate of the TWP 7025 E

Delivery head and flow rate

Delivery head and flow rate of the TWP 11025 E