Our website uses cookies to ensure a better performance and to measure page visits. Find out more about our use of cookies or how to change your settings, delete or turn off cookies at any time. Otherwise, we'll assume you're OK to continue with cookies in use. Accept

Drainage Drainage


  • Failure mode The drain hole can gradually block with debris and ice, causing flooding inside the unit.
  • Durability feature Better design of drain channels and the drain hole as well as an external drain pipe that will not freeze. Cleaning instructions should include a remo
  • Cost

Good practices

  • Good practicesWide drain channels and hole
  • Good practices External drain pipe
  • Good practices Clear cleaning instructions
  • Good practices Plunger/brush provided

Bad practices

  • Bad practicesNarrow drain channels and hole
  • Bad practices Rough surfaces and crevices
  • Bad practices In-mould drain pipe
  • Bad practices No plunger/brush

Key facts

  • Which? Consumer surveys indicate some of the most common faults relate to bad smells, mould and leaks. 
  • Around 1 in 3 of all fridges replaced in the UK each year failed to meet customer’s expectation for an 8 year product lifetime. 
  • Which? surveys show that the most common faults are build-up of ice, blocked drain and flooding in unit.

Icon key

  • Failure mode Failure mode
  • Durability features Durability features
  • Cost saving Cost saving
  • Low cost Low cost
  • Cost neutral Cost neutral
  • High cost High cost

Key failure modes

Early and later in lifetime

It is common for a fridge’s drain channels and drain hole/pipe to block with debris and ice, causing flooding in the fridge compartment during defrost cycles. 

By specifying drainage requirements  and providing clear cleaning instructions, blockages and flooding can be avoided.   

Specification for improved performance

The specification below provides the recommended improvements needed to improve product durability. They are ranked from bronze to gold based on the effectiveness of the change in improving durability, with bronze being the minimum and gold being the maximum.

Drainage channels to be smooth and appropriate dimensions

  • Drain channels and drain hole surfaces to be as smooth as possible without rough finishes or sharp corners which can trap water and dirt.
  • Where a drain hole is necessary to aid the defrost cycle, this should be on the rear vertical wall of the liner.
  • Drain hole to be circular with minimum diameter 10mm and maximum diameter 12mm for the full depth through the moulding to the rear of the unit and including pipe leading to the drain water tray.
  • Associated water drain channels (feeding into the drain hole) should be of adequate width (e.g. ~20mm front to back) and depth (e.g. ~10mm top to bottom) and angle (e.g. ~10 to 20 degrees front to back and side to side) looking into the fridge compartment, to drain effectively.
  • A plastic plunger, ideally tethered in the drain hole, to facilitate user cleaning. 
  • Quality control procedures to be in place and documented to check for the above characteristics

Drain moulding profile; anti-friction coating

  • The drain pipe should be free of the rear moulding and close to the heat exchange radiator to prevent any ice build-up.
  • Food grade dry anti-friction coating on drain channels and drain hole in liner moulding.

Multi-air flow humidity control

  • Multi-air-flow humidity-controlled fridges do not need a defrost cycle or a drain hole and provide more even overall cooling

Testing to demonstrate performance

Look at the drainage arrangements (channels, hole, pipe) to check that they meet the characteristics noted above.

Ask for clear evidence of meeting the requirements listed above, e.g.:

  • technical specifications, drawings, photographs
  • test data, quality control data

Cost implications

Improved reliability of components can reduce early returns and improve brand reputation which, in turn, can lower business costs and increase long-term sales.

To calculate overall cost savings for your business, use the WRAP cost/benefit analysis tool (currently in draft form and available on request).



Clear Instructions/Removable  Sticker
Clear instructions will reduce the possibility of returns through user-error.

Inspection procedures
Simple inspection procedures will help to identify manufacturing faults and component issues, reduce failure rates and customer returns.

Low cost

Cleaning plunger
Including a cleaning plunger brush and instructions for its use will help the user to keep the drain hole clean.

Drain channels and drain hole – new profile
The interior liner of a fridge is normally a single piece moulding.  It may be possible to modify the tooling to increase the drain hole aperture and shape of the drain channels.

New drain pipe
New drain pipe, clear of the rear moulding will help to reduce blockages.

Food grade anti-friction coating
A coating will help to keep the drain hole clean and reduce blockages.

High cost

Multi air flow humidity control
Multi-air-flow humidity-controlled fridges do not need a defrost cycle or a drain hole and provide more even overall cooling.