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Clear water vs dirty water submersible pump

Updated: 22 October 2026

Two Gardena boxes both say 20,000 litres per hour, and the titles do not say which limit matters. One number is how large a piece of grit may pass. The other is how little water the manufacturer claims to leave. A clear water vs dirty water submersible pump choice is that split. The rows, with amazon.co.uk prices from 21 October 2026, are on the [Gardena submersible pump comparison](/hub/garden-watering/gardena-submersible-pump). Peter F. used the Gardena UK pages and the stored reviews. There is no laboratory test. A qualifying purchase can earn us a commission at no extra cost to you.

Two Gardena boxes both say 20,000 litres per hour, and the titles do not say which limit matters. One number is how large a piece of grit may pass. The other is how little water the manufacturer claims to leave.

Our top picks

Gardena Gardena clear 20000

Best overall

Gardena Gardena clear 20000
6.2/10about £50.99
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Gardena Gardena dirty 20000

Alternative

Gardena Gardena dirty 20000
5.6/10about £55
View offer
Gardena Gardena 2-in-1 20000

Alternative

Gardena Gardena 2-in-1 20000
5.1/10about £59.99
View offer
On this page
  1. 1.Two different limits
  2. 2.What Gardena prints
  3. 3.What one roof puddle did
  4. 4.2-in-1 and the other pumps

Two different limits

Particle size is what the pump can swallow. Residual depth is the film the maker claims to leave. A 35 mm pump can still stop in a shallow puddle. A 1 mm claim can clog on grit. 20,000 litres per hour is not the flow at 9 metres. The UK pages put 0.9 bar and 9 metres. Use clear water when the last millimetres matter on that claim. Use dirty water for grit to 35 mm if you do not need a dry floor. The 1.3 bar barrel pump is the best Gardena submersible pump only for a butt and a hose.

What Gardena prints

Clear-water 20000, article 9016-28, states about 1 mm residue, a start from about 10 mm, and no 35 mm figure. Listing B0DNFSZMT8 is £50.99. The title says 09016-47. The technical field says 09016-28. Bloomling calls 09016-47 a European plug. Five reviews cannot rank it. Dirty-water 20000, article 9017-28, states grain to 35 mm, 0.9 bar and 9 metres. Listing B0DMFB5QJQ was £55, with 3.8 from 4 reviews, a 09017-47 title and a 09017-28 part field. Its bullets also say about 1 mm. Read that as a listing line, not as the UK page. Neither is a sewage pump. Setup is on how to use a Gardena submersible pump.
Gardena Gardena clear 20000

Testsieger

Gardena Gardena clear 20000
6.2/10about £50.99
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What one roof puddle did

One UK review of B0DMFB5QJQ says a puddle of at least 20 mm on a flat roof did not move. That single review, among four ratings, does not prove the pump faulty. Twenty millimetres is deeper than the 1 mm claim and the 10 mm start on the clear-water page. A roof is a sheet, not a sump, so a float may never lift. Treat 1 mm as Gardena's stated residue.

2-in-1 and the other pumps

The 2-in-1, article 09018-28, prints both 35 mm and about 1 mm. Listing B0DMFCXS9Z agrees on that article, at £59.99, with three reviews. TradePoint showed £70 including VAT. The FOTING 550 W, at £39.99, states residual water to 3.8 cm, which is the explicit line if a broom can finish the job. Its plug is unstated. Clean water points to the clear-water 20000, or to the 2-in-1 if grit may appear. Grit without a need for the last millimetre points to the dirty-water 20000.

Common questions

Can a dirty-water pump also suck a floor dry?
Not on the evidence in this set. Gardena UK leads the dirty-water 20000 with a 35 mm grain size for flood and pond drainage. The amazon bullets also say about 1 mm, and one UK review could not move a roof puddle of at least 20 mm. A float that needs a sump will not chase a sheet of water. Use the clear-water claim, or the 2-in-1, when the last millimetres are the point, and still treat 1 mm as a manufacturer figure.
What does 35 mm actually allow through?
Gardena UK states grain up to 35 mm on the dirty-water 20000 and on the 2-in-1. That is small stones, leaves and debris in flood or pond water. It is not a sewage rating, and it is not a reason to pump water around house sockets. A clear-water pump has no 35 mm figure. Sand that would pass the dirty-water pump can clog the clear-water one.
Is 1 mm a guarantee?
No. It is Gardena UK's stated maximum residue for the clear-water 20000 and a figure the 2-in-1 page also prints. The clear-water page adds a start from about 10 mm. One review on the dirty-water ASIN, where the bullets also say 1 mm, reported a 20 mm roof puddle that did not move. That single review does not disprove the clear-water page. It does stop us treating every 1 mm bullet as observed fact.
Which amazon model is the clear-water one?
B0DNFSZMT8, at £50.99, is the clear-water 20000 in this capture. The title says 09016-47. The technical field says 09016-28, which is the article on the Gardena UK clear-water page. Bloomling calls 09016-47 a European plug. Check the plug in the photos. The dirty-water listing is B0DMFB5QJQ, with the same kind of -47 title and -28 part field.
What does the 2-in-1 add?
It is the Gardena UK page that states both 35 mm and about 1 mm. The amazon ASIN is B0DMFCXS9Z at £59.99, and the title and the part field agree on 09018-28. TradePoint showed £70 including VAT. You still buy the hose, the review count is three, and watts and head were not filled in our stored fields. Choose it when the water might be gritty and you still want the flat-suction claim on the same pump.
Will a clear-water pump survive leaves and grit?
Gardena UK limits the clear-water 20000 to clear or slightly polluted water, with a 1 mm residue claim and no 35 mm passage. Leaves and grit are the dirty-water job, or the 2-in-1. A blocked clear-water impeller is the usual result of asking it to eat what the dirty-water pump is specified to pass.

Related pages

Gardena submersible pump buying guide

Gardena submersible pump

Best Gardena submersible pump for a rainwater butt

How to use a Gardena submersible pump: the float and RCD

Gardena water butt pump for stored rain and a hose

Sources

Public UK sources from the research digest, plus the amazon.co.uk prices, stars and review counts captured for these ten listings on 21 October 2026. Last reviewed 22 October 2026.

  1. Gardena UK, rain water tank pump 4000/1 (retrieved 21 October 2026)
  2. Gardena UK, dirty-water submersible pump 20000 (retrieved 21 October 2026)
  3. Gardena UK, 2-in-1 clear/dirty submersible pump 20000 (retrieved 21 October 2026)
  4. Gardena UK, clear-water submersible pump 20000 (retrieved 21 October 2026)
  5. Gardena UK, battery rainwater tank pump 2000/2 18V (retrieved 21 October 2026)
  6. IET Wiring Matters, Regulation 411.3.3 and 30 mA RCDs (retrieved 21 October 2026)
  7. Water Regs UK, alternative water systems (February 2024) (retrieved 21 October 2026)
  8. South West Water, hosepipe ban exceptions (retrieved 21 October 2026)