Sewage and Drainage Pumps
A submersible drainage or sewage pump sits in the water it moves – in a sump, septic tank, pit, flooded basement or excavation – and pushes it up and away to a drain, sewer or discharge point. Choosing one comes down to four questions: what is in the water, how much of it you need to move, how high and far it must go, and what power is on site. This guide takes you through each, with the pump types, impeller choices, installation essentials and current South African price ranges.
Power Range
0.25 – 45 kW
230V, 400V and 525V
Solids Passage
Up to 80 mm+
Depends on impeller and size
Drainage Pumps
From about R1 210
Incl. VAT
Sewage Pumps
From about R1 980
Vortex, channel and cutter
Self-Cleansing Velocity
0.7 m/s minimum
In the rising main
Pump Types
8 families
Clean water to slurry
Which type of pump do you need?
Start with what is in the water. A pump built for clean rainwater will block or wear out quickly in sewage or sand, and a heavy slurry pump is expensive overkill for a flooded garage. The table below matches the liquid to the pump family.
| Pump type | Handles | Typical uses |
|---|---|---|
| Clean-water drainage | Clear water with fine particles up to about 5 – 10 mm | Pools, rainwater tanks, ponds, flooded rooms, water transfer |
| Dirty-water drainage | Water with sand, mud, leaves and solids up to about 25 – 35 mm | Flooded basements, storm-water sumps, construction runoff |
| Sewage – vortex impeller | Raw sewage, fibrous and stringy solids, some sand | Septic tanks, household sumps, grey and black water |
| Sewage – channel impeller | Screened or raw sewage with solids, at higher efficiency | Pump stations, larger buildings, continuous duty |
| Sewage – cutter / grinder | Raw sewage, chopped before it enters the pipe | Long, small-bore rising mains and pressure sewers |
| Dewatering | Large volumes of sandy, muddy water | Construction excavations, mines, quarries, trenches |
| Slurry | Heavy, abrasive sand and mineral slurry | Mining sumps, sand washing, settling ponds |
| Toilet shredder / lifting station | Toilet, basin and shower waste | A bathroom below the level of the sewer line |
Vortex, channel or cutter impeller?
For sewage the impeller type matters more than the brand. Each design trades clog resistance against efficiency in a different way.
| Impeller | How it works | Strengths | Trade-off |
|---|---|---|---|
| Vortex | The impeller is recessed and spins a whirlpool; most solids never touch it | Lowest clogging risk, handles stringy material and sand well | Lower hydraulic efficiency, so higher running cost |
| Open / closed channel | Solids pass through one or two wide channels in the impeller | Higher efficiency, good for continuous duty and higher heads | Wipes, rags and fibres can wrap and block |
| Static cutter / grinder | A cutting blade chops solids before the impeller | Allows small-diameter discharge pipes and long pressure lines | Lower flow; cutter wears and needs inspection |
Wipes are the number one cause of blocked sewage pumps. “Flushable” wet wipes do not break down. Where they cannot be kept out, choose a vortex or cutter pump over a channel impeller.
Sizing a pump in four steps
1. What is in the water?
Note the largest solid the pump must pass and whether there is sand or grit. Check the pump's rated solids passage in millimetres against the discharge pipe size: the pump should never pass a solid bigger than the pipe can carry.
2. How much flow?
For drainage, estimate the volume to remove and the time you have: a 20 000 litre flooded basement emptied in two hours needs about 10 m³/h. For sewage, size to the peak inflow into the sump, not the daily average.
3. What is the total head?
Total head is the vertical lift from the pump to the highest discharge point, plus friction loss in the pipe and fittings. As a rule of thumb, add about 1 m of head for every 10 m of horizontal pipe in typical household sizes, then read the flow at that head from the pump curve.
4. What power is on site?
Household and small commercial jobs run on 230V single phase up to about 2.2 kW. Larger pumps, pump stations and continuous-duty work use 400V three phase, and mining sites often use 525V.
Rising main velocity: keep it moving
Sewage must flow fast enough in the discharge pipe (the rising main) to carry solids and scour grease and sand. The European standard EN 752 sets a minimum self-cleansing velocity of about 0.7 m/s. Too slow and solids settle and block the line; too fast (above about 2.5 – 3 m/s) and friction losses and wear rise sharply.
| Pipe inside diameter | Flow for 0.7 m/s | Flow for 1.5 m/s |
|---|---|---|
| 32 mm | 2.0 m³/h | 4.3 m³/h |
| 40 mm | 3.2 m³/h | 6.8 m³/h |
| 50 mm | 4.9 m³/h | 10.6 m³/h |
| 65 mm | 8.4 m³/h | 17.9 m³/h |
| 80 mm | 12.7 m³/h | 27.1 m³/h |
| 100 mm | 19.8 m³/h | 42.4 m³/h |
Do not oversize the pipe. A pump that suits a 50 mm line can leave a 110 mm pipe running far below self-cleansing speed. Match the pipe to the pump flow, not to the sewer.
Installation essentials
- Float switch – automatic pumps have one built in; for manual pumps fit a float switch so the pump starts and stops with the water level and never runs dry.
- Sump size – make the sump large enough that the pump runs at least a minute or two per cycle. Too small a sump causes rapid on-off cycling and burns out motors.
- Stand the pump off the floor – on a base or a few bricks, so it does not suck up settled mud and stones.
- Non-return valve and gate valve – on the discharge, so the pipe does not drain back into the sump each time the pump stops. Use a ball-type non-return valve for sewage.
- Lifting chain or rope – never lift a submersible pump by its power cable.
- Duty and standby – for pump stations and critical sumps, install two pumps with an alternating controller and a high-level alarm.
Price guide
Current price ranges on our store, including VAT. Prices vary with power, head and construction material.
| Pump range | Typical price range |
|---|---|
| Clean-water plastic submersible pumps | R1 210 – R1 370 |
| Dirty-water and stainless drainage pumps (AquaDuty, Vansan) | R1 330 – R6 120 |
| Leo XKS garden submersible pumps | R2 060 – R4 750 |
| Vega screened sewage pumps (open channel, cast iron) 230V | R1 980 – R5 690 |
| Vega stainless steel vortex sewage pumps | R4 330 – R4 550 |
| Wilo drainage pumps | R4 650 – R8 770 |
| Leo XSP sewage pumps | R3 180 – R14 670 |
| Leo SWU / SWEM / SWP sewage pumps 230V | R7 730 – R11 380 |
| Vega raw sewage static cutter pumps | From about R8 140 |
| Leo toilet shredder / lifting station | About R6 830 |
| Leo WQ sewage pumps 400V (1.1 – 45 kW) | R6 450 – R131 950 |
| Meudy KBZ dewatering pumps (1.5 – 15 kW) | R11 510 – R69 060 |
| Meudy KBS slurry pumps | R40 050 – R230 640 |
Prices are indicative and subject to change. See each product page for the current price.
Shop the range
| Application | Ranges on our store |
|---|---|
| Clean water drainage | AquaDuty clean-water plastic, Vansan aluminium clean-water, Leo garden submersible, Leo XKS |
| Dirty water drainage | AquaDuty dirty-water plastic, AquaDuty stainless steel, Vansan dirty-water, Wilo drainage, Meudy drainage |
| Household sewage 230V | Leo sewage 230V, Leo XSP, Vega open channel, Vega stainless vortex |
| Raw sewage and pump stations | Vega static cutter, Vega channel impeller, Leo sewage 400V, Leo WQ 400V, Duckfoot WQ |
| Chemical sludge | Vega WQF 316L stainless steel |
| Dewatering and slurry | Meudy KBZ dewatering, Meudy KBS slurry |
| Toilet below sewer level | Leo toilet shredder pumps |
| Level control | Leo float switches |
Frequently asked questions
What is the difference between a drainage pump and a sewage pump?
A drainage pump moves clean or lightly dirty water with small particles. A sewage pump has a vortex, channel or cutter impeller and a larger solids passage to handle toilet waste, fibres and solids without blocking.
Can I use a drainage pump in a septic tank?
Not for raw sewage. Septic tank contents include solids and fibres that block a drainage pump. Use a sewage pump with a vortex or cutter impeller. A clean-water or dirty-water pump can be used on the clarified outlet chamber only.
What size solids can a sewage pump pass?
Small household sewage pumps pass about 25 – 35 mm, larger vortex and channel pumps 50 mm or more, and big WQ pumps 80 mm and above. Cutter pumps chop solids so they can use a small discharge pipe.
Do I need a float switch?
Yes, for any unattended sump. Automatic pumps have one built in; manual pumps need an external float switch so the pump starts with rising water and stops before it runs dry.
What is a dewatering pump?
A robust submersible pump built to remove large volumes of sandy, muddy water from excavations, mines and flooded sites. It uses wear-resistant materials to survive abrasive water that would destroy a standard drainage pump.
How far can a sewage pump push waste?
It depends on the pump curve. Add the vertical lift to the friction loss of the pipe run to get the total head, then check the pump delivers enough flow at that head to keep at least 0.7 m/s in the pipe.
Can I install a toilet below the sewer line?
Yes, with a toilet shredder or lifting station. It collects the waste, macerates it and pumps it up through a small pipe to the sewer, so a bathroom can go in a basement or below the main drain.
Why does my sewage pump keep blocking?
Most blockages come from wet wipes, rags and sanitary products wrapping around a channel impeller. Keep them out of the system, or change to a vortex or cutter pump. Also check the pump is not sitting in settled sludge.
Should I choose 230V or 400V?
Homes and small buildings use 230V single-phase pumps up to about 2.2 kW. Pump stations, larger buildings and continuous industrial duty use 400V three phase, which allows bigger motors and better starting.
How much does a sewage pump cost in South Africa?
Household sewage pumps start from about R1 980 and most 230V models fall between R4 000 and R12 000. 400V WQ pumps run from about R6 450 to over R130 000 for 45 kW, including VAT.
Not sure which pump you need?
Tell us what you are pumping, the size of the sump or area, how high and how far it must go, and the power on site. We will size the pump, float switch and pipe for you.
Related ranges
- Sewage, Drainage & Dewatering Pumps — the full category
- Borehole Pump Guide — submersible borehole pumps, motors and control boxes
- Booster Pump Guide — household water pressure
- Solar Pump Guide — off-grid water supply