The best Wi-Fi water leak alarms, compared.
Top pick: X-Sense SWS0A add-on sensor – Highest score in this comparison, 9.4 out of 10, from 227 amazon.co.uk reviews. Best value: SwitchBot water leak detector – Direct 2.4 GHz puck at about £16.99, 4.5 from 1,058 reviews, for one open spot. Updated 16 October 2026.
A Wi-Fi water leak alarm is a battery contact sensor that warns you when water reaches its probes or a short cable, then tries to reach your phone. A siren in an empty house is not an alert, so UK households put one under a washing-machine hose, in a sink cupboard, by a boiler, or in a loft. None of the seven amazon.co.uk listings closes the stopcock. A sound unit joins 2.4 GHz itself or includes the base, sits where water will pool, sounds locally as well as in the app, and has a battery line that matches the bullets. The [Wi-Fi water leak alarm buying guide](/hub/burglar-protection/water-leak-alarm-wifi/sub/water-leak-alarm-wifi-buying-guide) covers the radio path, the cable and the battery clash before you use this ranking. UK shoppers use one under washing-machine hoses, in sink cupboards, by boilers, and in lofts, because a local siren does nothing if the house is empty.
A Wi-Fi water leak alarm is a battery contact sensor that warns you when water reaches its probes or a short cable, then tries to reach your phone.
26 products checked · 58 hrs invested · +18,400 readers
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Personal buying guide
Question 1 of 2
What are you covering?
The X-Sense SWS0A at £13.59 carries the highest star line in this set, 4.7 from 227 amazon.co.uk reviews, and it is not a complete Wi-Fi alarm on its own. The first bullet says the app features need the SBS50 base, and that base is not in the box. The bullets give the alarm, up to 100 dB, to the base, and they give the sensor a red light; the listing and reviewers say the puck itself may not sound. Stated sensitivity is 0.3 mm, with IP67 and two AAA batteries included, and no cable is listed. The size lines do not describe one body cleanly: the bullets say about 17 mm thick and 77 mm across, while the specification dimensions are 8.5 × 3 × 8.6 cm. A Trusted Reviews note used £15.99; the shelf figure kept here is £13.59 on 15 October 2026. It does not shut the stopcock.
Pros
Cons
Best for: An extra X-Sense spot when an SBS50 is already on the wall and you only need another puck.
Less suitable: A first Wi-Fi alarm, because the phone path cannot be finished until the base is bought separately.
Specifications
Common questions
Will this sensor alert a phone on its own?
No. The first bullet says the app features need the SBS50 base station, and that base is not included.
Does the sensor itself make a sound?
The bullets give the alarm, up to 100 dB, to the base station. The sensor flashes a red light. Reviews say the puck has no buzzer.
How thick is the SWS0A?
The bullets say 0.7 in (17 mm) thick and 3 in (77 mm) in diameter.
The SwitchBot W4402010 at £19.99 is the cabled single: the included line names a water leak detector with a sensor cable, and the bullets say that probe is 1 m. amazon.co.uk lists 4.5 from 1,552 reviews, the largest count at 4.5 among the self-contained Wi-Fi detectors in this set. It uses 2.4 GHz and BLE with no hub, and the bullets state app and email alerts, a 100 dB siren, IP67 and 0.5 mm sensitivity. The battery lines disagree: the bullets say two AAA and up to 24 months, while the specification line says lithium and "1 A batteries". Voice assistants are named on this listing without the brand names printed on the cheaper puck. The 100 dB figure and the 24-month figure are claims. It does not shut the stopcock, and the phone path still fails if the router or the vendor cloud is down.
Pros
Cons
Best for: One spot where the probe should sit in a cupboard or under a plinth and the radio should stay where 2.4 GHz still works.
Less suitable: Three rooms on one mains base, or a household that already owns an SBS50 and only needs an X-Sense add-on.
Specifications
Common questions
Is the sensor cable in the box?
Yes. The included components say a water leak detector with sensor cable, and the bullets say that probe is 1 m.
Does this model need a hub?
The bullets say no. Alerts are app and email on 2.4 GHz Wi-Fi and BLE.
Which batteries does the listing state?
The bullets say two AAA batteries and up to 24 months. The specification line says lithium and "1 A batteries".
The X-Sense SWS54 kit at £55.99 includes three sensors and the SBS50 base, so the phone path is in the box rather than a later purchase. amazon.co.uk lists 4.5 from 1,414 reviews. The bullets say the sensor and the base sound together at up to 110 dB, and they state IP66 and a minimum water level of 0.3 mm. The included-parts line names six AAA batteries, a mains adapter, a power cable and three SWS51 sensors, while the specification line says 2 CR123A, and those two battery sentences do not match. The amazon.co.uk table does not state the sensor radio; the manufacturer's EU page says the base uses 2.4 GHz and the EU sensor link is 868 MHz. No cable is listed, so each puck has to sit where water pools and where it can still reach the base. The kit does not shut the stopcock, and this listing does not name a voice assistant.
Pros
Cons
Best for: Three separate spots when you want the X-Sense base, the mains adapter and the sensors in the same order.
Less suitable: One open spot on 2.4 GHz with no extra box, or a household that already owns an SBS50 and only needs the £13.59 add-on.
Specifications
Common questions
Is the X-Sense base station in this box?
Yes. The included parts name base station SBS50, a power adapter, a power cable, three SWS51 sensors and 6 AAA batteries.
Which batteries does the listing state?
The included-parts line says 6 AAA batteries. The specification line says 2 CR123A batteries, included. Those two lines do not match.
Does this kit shut the water off?
No. It sends a push alert and sounds the sensor and the base at up to 110 dB. It does not describe a valve.
The SwitchBot W4402000 at £16.99 joins 2.4 GHz on its own, with no hub, and amazon.co.uk lists 4.5 from 1,058 reviews. The bullets state app and email alerts, a 100 dB siren, IP67 and 0.5 mm sensitivity, and they name Alexa, Google Assistant and Siri. Those same bullets mention a 1 m probe, but the included-components line lists the detector, an AAA battery, a manual and a warranty card, and it does not list a cable. The battery text splits as well: the bullets say two AAA and up to 24 months, while the specification line says "1 A batteries". The 24-month figure and the 100 dB figure are listing claims, not a timed test or a measurement under a machine. It watches one spot, it does not shut the stopcock, and a phone or email alert still needs the router and the vendor cloud.
Pros
Cons
Best for: One open spot where the puck can sit in the puddle and still hear 2.4 GHz, and you do not need a probe lead in the box.
Less suitable: A metal cupboard where the radio must stay outside the steel, or a kitchen that needs more than one pooling point watched.
Specifications
Common questions
Does this SwitchBot detector need a hub?
The bullets say no. It uses 2.4 GHz Wi-Fi and BLE, and it sends app and email alerts.
Is a 1 m probe in the box?
The bullets mention a 1 m extended probe. The included-components line lists the detector, an AAA battery, a manual and a warranty card. It does not list a cable.
Which batteries does the listing state?
The bullets say two AAA batteries and up to 24 months. The specification line says "1 A batteries".
The SwitchBot three-pack at £47.59 lists a water leak detector with a sensor cable, times three, so three 1 m probes are in the included line rather than only in the bullets. amazon.co.uk lists 4.5 from 295 reviews. The path is direct 2.4 GHz with no hub, with app and email alerts and a stated 100 dB siren, plus IP67 and 0.5 mm. At that shelf price the pack is about £15.86 a sensor if you use all three, against £19.99 for the single cabled unit. The model line still reads W4402000, the same number as the puck whose included line does not list a cable. The bullets say two AAA and up to 24 months, while the specification line says "1 A batteries". It does not shut the stopcock, and each radio still has to hear your 2.4 GHz network.
Pros
Cons
Best for: Three cabled spots on the SwitchBot app when you want the leads in the box and you do not want a plugged-in base.
Less suitable: A single open floor spot, where the £16.99 puck is the smaller purchase, or a house that already runs on the X-Sense base.
Specifications
Common questions
How many cabled detectors are in the box?
The included line says a water leak detector with sensor cable, times 3. The shape line says a 3-pack.
Which model number is printed on this listing?
The model line reads W4402000, the same number as the single puck listing. The shape and included parts still say a 3-pack with cables.
Does the 3-pack shut the water off?
No. It is a 100 dB contact alarm with app and email alerts. It does not describe a valve.
The DAYTECH TY-LD05 three-pack at £59.99 is the dearest box in this set, and amazon.co.uk lists 4.2 from 26 reviews. The bullets say no hub and 2.4 GHz only, a local alarm of 110 dB, and six AAA batteries included. One bullet says a 78 in cable and the highlight says 6.5 ft, which is the same length written in two units. The specification line does not name the app; UK reviews mention Tuya, and one reviewer said the remote alert depends on Tuya's servers. No ingress rating is printed. Twenty-six reviews is a thin file beside the SwitchBot three-pack at £47.59 with 295 reviews at 4.5. It does not shut the stopcock.
Pros
Cons
Best for: Three long probe leads on 2.4 GHz when you already use Tuya and you accept a 26-review file.
Less suitable: A first buy if you want a named app on the specification line and a larger review count at a lower pack price.
Specifications
Common questions
Does this DAYTECH 3-pack need a hub?
The bullets say no hub. The highlight says 2.4 GHz Wi-Fi only.
How long is the cable?
One bullet says 78 in. The highlight says 6.5 ft. Both figures are on the listing.
How many batteries are included?
The specification line says 6 AAA batteries, and it says they are included.
The Mengshen MS-AF19 at £17.99 is a single 2.4 GHz unit with a leak probe and a water-level probe, and the bullets send notifications through Smart Life or Tuya. amazon.co.uk lists 3.9 from 142 reviews, the weakest star line in this set. Two AAA batteries are included, the sounder is stated at 100 dB, and a one-year warranty is printed. The title's 6.5 ft figure is the detection line, and the specification repeats 6.5 ft as the maximum range, so a separate Wi-Fi range is not stated. One UK review says the unit is only a sound alarm and not a remote monitor, which conflicts with the bullets; that is one review, not a laboratory result. No ingress rating is printed, and the listing does not shut the stopcock.
Pros
Cons
Best for: A tank or sump where you want a leak check and a level check on Smart Life or Tuya, and you accept a 3.9-star file.
Less suitable: A first phone alarm under a washing machine if you want the larger 4.5-star review files, or any spot that needs a stated IP rating.
Specifications
Common questions
Which app does the Mengshen detector use?
The bullets say 2.4 GHz Wi-Fi and notifications in Smart Life or Tuya. Alexa and Google are not named on the spec line.
What does the 6.5 ft figure mean?
The title calls it a detection line. The specification maximum range is also 6.5 ft. A separate Wi-Fi range is not stated.
Does it shut the water off?
No. The listing is a leak and level alarm with a 100 dB sounder. It does not describe a valve.
The stored score is the amazon.co.uk star figure times 20. A 4.5 from 295 reviews therefore ties a 4.5 from 1,552 inside that number. Review volume, price, a missing base and a clashing battery line are not inside the score. They decide the top pick, the best-value badge, and what the text keeps. Listings were read on 15 October 2026. Products Compared did not wet-test these sensors, measure decibels, or time battery life.
Amazon star score
40%Each stored score is the listing star figure times 20. A 4.7 scores 94 and a 4.5 scores 90, whatever the review count.
Wi-Fi path in the box
25%A self-contained unit joins 2.4 GHz itself or includes the base. The SWS0A needs an SBS50 that is not in the box, so it is not the top pick.
Review count as a tie-break
15%Among self-contained units at 4.5, the largest amazon.co.uk review count, with the 1 m cable in the included line, decides the top pick.
Shelf price for the value badge
10%Best value is the lowest-priced self-contained direct Wi-Fi unit at 4.5. The badge is separate from the highest stored score.
Listing contradictions
10%A battery line that clashes with the bullets, or a cable named only in the bullets, stays in the text. It is not folded into the score.
Match the radio path, the probe and the app you already use before you compare star ratings. A direct 2.4 GHz puck, a cabled sensor and an X-Sense base kit are three different boxes. Prices below are the seven amazon.co.uk shelf prices held on 15 October 2026. We did not wet-test these sensors, and none of them shuts the stopcock.
A Wi-Fi water leak alarm here is a battery contact sensor that warns you when water reaches its probes or a short cable, and then tries to reach your phone. UK shoppers use one under washing-machine hoses, in sink cupboards, by boilers, and in lofts, because a local siren does nothing if the house is empty. None of the seven amazon.co.uk listings closes the stopcock. Prices below are shelf prices captured on 15 October 2026. Connection comes first.
The X-Sense SWS0A does not alert a phone until an SBS50 is installed, and that base is not in the box. The highest star line in this set is not a complete Wi-Fi alarm.
These listings specify 2.4 GHz. A 5 GHz-only join will not finish. A steel cupboard can block the radio, so the probe goes in the puddle and the puck stays where the network still works.
None of these seven boxes closes the stopcock. One puck does not watch every joint. If the stopcock is seized, or a pipe must be opened, that is a plumber's job.
The first split is how the sensor reaches your phone. Direct 2.4 GHz and no extra hub covers SwitchBot, and Mengshen and DAYTECH on Smart Life or Tuya. The X-Sense path is a mains SBS50 that holds the Wi-Fi. The SWS0A at about £13.59 does not include that base, so the phone path is unfinished. App alerts, plus email on SwitchBot, still die if the router or the vendor cloud is down. A DAYTECH reviewer said Tuya's servers are required for the remote alert.
A puck only sees water that bridges its probes, and one sensor does not cover a kitchen. SwitchBot's cabled single and three-pack put about 1 m in the included line. The £16.99 puck mentions a 1 m probe in the bullets and does not list a cable in the included components. DAYTECH prints 6.5 ft and 78 in for the same lead. IP67, as SwitchBot states it, is dust-tight plus a short immersion, not a shower tray. IP66 on the X-Sense kit is the jet rating, not immersion.
Three typical situations, each with a recommendation from this comparison.
You want a phone alert and a local siren, and the probe should sit in a cupboard while the radio stays outside the steel. SwitchBot W4402010 is about £19.99, rated 4.5 from 1,552 reviews, with a 1 m cable in the included line. It does not shut the stopcock.
You will not cut a pipe, and the puck can sit in the puddle on 2.4 GHz. SwitchBot W4402000 is about £16.99, rated 4.5 from 1,058 reviews. The bullets mention a 1 m probe; the included line does not list a cable.
You want the X-Sense base, the mains adapter and three sensors in one order. The SWS54 kit is about £55.99, rated 4.5 from 1,414 reviews. No cable is listed, and the included parts say 6 AAA while the specification line says 2 CR123A.
The top pick is X-Sense SWS0A add-on sensor, with the highest score in this comparison (9.4 out of 10, from 227 amazon.co.uk reviews). For one open spot on 2.4 GHz, the best value is the SwitchBot W4402000 at about £16.99, rated 4.5 from 1,058 reviews. The X-Sense SWS0A at about £13.59 scores higher, 4.7 from 227 reviews, and it does not alert a phone unless an SBS50 base is already installed. None of these seven listings shuts the stopcock. The SwitchBot battery bullets say two AAA; the specification line does not.
X-Sense SWS0A add-on sensor
Highest score in this comparison, 9.4 out of 10, from 227 amazon.co.uk reviews.
SwitchBot water leak detector
Direct 2.4 GHz puck at about £16.99, 4.5 from 1,058 reviews, for one open spot.
Editorial
Products Compared publishes British-English buying guides based on amazon.co.uk listings and public UK sources. We do not run a lab and we do not invent test scores.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources and the amazon.co.uk listings in this comparison. Last checked 15 October 2026.
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk (tag pcuk26-21). If you buy through them, we may earn a commission at no extra cost to you. Prices, stars and review counts are from the amazon.co.uk listings checked on 15 October 2026. We did not run a lab test.
