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Water leak detector under a washing machine

Updated: 16 October 2026

The washer has finished a cycle, the floor at the back is dark, and you are deciding whether the sensor goes under a foot, on a shelf, or in the puddle. A water leak detector under a washing machine only helps if the probes meet the water first and the radio can still call your phone. The [Wi-Fi water leak alarm comparison](/hub/burglar-protection/water-leak-alarm-wifi) is the seven amazon.co.uk listings from 15 October 2026. This page is the floor plan, not the pairing steps and not a ranking. The Products Compared editorial team did not flood a kitchen. A qualifying purchase can earn a commission at no extra cost to you.

The washer has finished a cycle, the floor at the back is dark, and you are deciding whether the sensor goes under a foot, on a shelf, or in the puddle.

Our top picks

SwitchBot SwitchBot detector with 1 m cable

Best overall

SwitchBot SwitchBot detector with 1 m cable
9.0/10about £19.99
View offer
SwitchBot SwitchBot water leak detector

Preis-Tipp

SwitchBot SwitchBot water leak detector
9.0/10about £16.99
View offer
SwitchBot SwitchBot 3-pack with 1 m cables

Alternative

SwitchBot SwitchBot 3-pack with 1 m cables
9.0/10about £47.59
View offer
On this page
  1. 1.Where the water pools
  2. 2.Keep the radio out of the metal
  3. 3.Splash, feet and the shower tray
  4. 4.Which shape from this set fits the gap

Where the water pools

A contact sensor sees one puddle, not the whole appliance. On a washing machine the usual first pool is the floor under the hoses and the drain standpipe, usually at the rear. Lay the probes flat there, or in a tray if the tray fills first. Do not leave the unit on a shelf or under a foot. A dishwasher often connects under the front plinth, or the hose runs to the sink. A puck behind the washer stays dry while that toe-kick fills. Under the sink, put the probes between the tails and the trap. At a boiler, use the floor where a relief pipe or condensate arrives.

Keep the radio out of the metal

The probes want the lowest corner. The radio wants 2.4 GHz. A cable is the split only if it is in your box. The SwitchBot W4402010, at £19.99, includes a 1 m sensor cable. The three-pack at £47.59 lists that cabled detector three times. The £16.99 puck mentions 1 m in the bullets and does not list a cable. DAYTECH prints 78 in and 6.5 ft, one length, not two cables. The X-Sense kit and the SWS0A list no cable, so the radio lives with the probes and talks to the SBS50. If even a cabled radio cannot hear 2.4 GHz, use the direct or base-station page. Wet-test on the table first, using the setup guide.
SwitchBot SwitchBot detector with 1 m cable

Testsieger

SwitchBot SwitchBot detector with 1 m cable
9.0/10about £19.99
View offer

Splash, feet and the shower tray

A shower tray is the wrong use of an IP67 claim. IP67, as SwitchBot states it, is dust-tight plus a short immersion. It is not a permit to live in the spray. IP66 on the SWS54 is a jet-water claim, not a pass for a bathroom floor. A puck under a washing-machine foot tilts until the probes point at the air. The SWS0A bullets claim about 17 mm thick and 77 mm across, and the specification dimensions are 8.5 × 3 × 8.6 cm, so measure the unit before you assume it slides under a plinth. Thinness does not add a cable, and the add-on still needs an SBS50.

Which shape from this set fits the gap

A 1 m cable in the box, the W4402010 or the SwitchBot three-pack, fits a washer rear or a dishwasher toe-kick where the radio must sit outside the metal. The £16.99 puck, with no cable in the included line, fits an open floor you can see, such as beside a boiler, if 2.4 GHz is honest there. The SWS54 sensors have no cable, so they belong where the base can hear them and the water pools. DAYTECH's longer lead fits a deep cupboard if you already use Tuya and you accept a 26-review file at £59.99. Mengshen's leak-plus-level probe is a tank or sump shape, not the first choice under a washer hose. None of these placements shuts the mains.

Common questions

Where do I put a leak detector under a washing machine?
Put the probes on the floor at the low point under the supply hoses and the drain standpipe, usually at the rear, or in a tray if the tray fills first. Keep the unit off a shelf and out from under a foot. A leak at the door or the filter is a second sensor, not a reason to leave the hoses unwatched.
Does the sensor go under the dishwasher or behind it?
Follow the hose. Many UK dishwashers connect under the front plinth, or the hose runs to the sink. A sensor behind the washer misses a puddle that starts at the toe-kick. A 1 m cable, when it is in the box, can lie in that kick space while the radio sits where 2.4 GHz still works.
Will Wi-Fi work inside a metal cupboard?
Often it will not. Cupboards and plumbing are what support notes blame when the link returns as soon as you move the unit. Keep the radio outside the void, and use a cable only if the included line lists one. The X-Sense pucks have no cable, so they have to sit where the base can still hear them.
How long a cable do these listings include?
The SwitchBot W4402010 and the SwitchBot three-pack include a 1 m sensor cable. The £16.99 puck mentions 1 m in the bullets and does not list a cable. DAYTECH prints 78 in and 6.5 ft, the same length. Mengshen's 6.5 ft is the probe line and the stated maximum range, not a separate Wi-Fi measurement. The X-Sense kit and the SWS0A list no cable.
Why does it beep when nobody is leaking?
The probes are bridging on splash, a drip or condensation. A sink used for wringing cloths, a shower tray and a washer door seal are typical causes. Move the sensor back from the splash, then wet-test again so the phone still alerts. Muting it without moving it leaves that corner silent the next time the hose fails.
Is one sensor enough for the kitchen?
No, if the washer, the dishwasher and the sink pool in different corners. Each contact sensor watches only the water that reaches it. A three-pack or the X-Sense kit covers several spots only where each radio, or each link to the base, still works. The loft and the boiler are further sensors, not a stretch of the kitchen puck.

Related pages

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Buying guide

Wi-Fi water leak alarms

Wi-Fi leak detector: no hub or a base station

How to set up a Wi-Fi water leak detector in the UK

Sources

Public UK sources and the amazon.co.uk listings in this comparison. Last checked 15 October 2026.

  1. GOV.UK: Radio Equipment Regulations 2017 (retrieved 15 October 2026)
  2. GOV.UK: regulations for consumer connectable product security (retrieved 15 October 2026)
  3. Ofwat: supply pipes (retrieved 15 October 2026)
  4. Building Regulations 2010, regulation 36 (retrieved 15 October 2026)
  5. Met Office: frozen or burst pipes (retrieved 15 October 2026)
  6. Aviva: water damage and escape of water (retrieved 15 October 2026)
  7. SwitchBot UK: water leak detector (retrieved 15 October 2026)
  8. X-Sense: SWS54 smart water leak detector kit (retrieved 15 October 2026)