Automation

Best Water Leak Sensors and Auto Shutoff Valves for Home Assistant

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A leak sensor that only sends a phone alert is a slow way to watch a kitchen flood. Somebody still has to get home and turn the main valve. What saves the floor is a water shutoff valve for Home Assistant to close, paired with leak sensors so one wet probe anywhere in the house shuts the main line. What decides whether that works on the night your internet is down is the path each device takes into Home Assistant, not the brand on the box.

Original content from computingforgeeks.com - post 178153

We cover clamp-on and inline shutoff valves plus the Zigbee, Z-Wave, Wi-Fi and Matter leak sensors that trigger them, ranked by how much of the chain stays local. None of the hardware was installed here, so specs come from the makers, the Home Assistant and Zigbee2MQTT docs and live Amazon listings. We confirmed the leak-to-valve automation working on Home Assistant 2026.10.4 in October 2026, with the internet cut and stand-in entities in place of real radios, and we rechecked the product links in November 2026.

Pick a water shutoff valve for Home Assistant

If you only read one part, read this. Every pick below has its own section further down with the trade-off that would make you skip it, and the prices are bands from today’s listings, so check the live price before you buy:

  • Best local shutoff valve: Zooz ZAC36 Titan (Z-Wave, about $170 to $200). It clamps over your ball valve, runs on mains with an optional battery, and its own wired probe closes it even if Home Assistant is off.
  • Best budget valve: Aqara Valve Controller T1 (Zigbee, about $70). Four AA batteries and no outlet needed, but Aqara publishes no water-ingress rating, so keep it out of wet pits and outdoor spots.
  • Best for a long run to the meter: YoLink Valve Controller 2 kit (LoRa, about $240 without a hub or $270 with hub and three sensors). It reaches far, but Home Assistant only sees it through YoLink’s cloud.
  • Best inline valve with flow monitoring: Moen Flo Smart Water Shutoff (Wi-Fi, about $560 for 3/4 in). It catches slow leaks no probe would, and Home Assistant can close it, but only through Moen’s cloud.
  • Best Zigbee leak sensor: ThirdReality Zigbee Water Leak Sensor (about $21), because it has its own 120 dB siren.
  • Best for wet locations: SONOFF SNZB-05P (Zigbee, about $23), IP67 with a five-year coin cell.
  • Best with no hub or coordinator: Shelly Flood Gen4 (Wi-Fi or Matter, about $40) with a 2 m sensing cable.

The two smallest picks, the Aqara Water Leak Sensor and the Zooz ZSE42 for Z-Wave homes, get their own sections too. Both are cheap enough to put under every sink, which is where most of the value in a leak system comes from.

Keep the shutoff logic local

A leak system has three hops: the sensor reports wet, something decides to act, and the valve motor turns. When all three stay inside the house, the shutoff fires with the router unplugged. When any hop goes through a vendor server, the shutoff depends on that server and on your internet link, which is exactly the thing a storm or a burst pipe in the utility room tends to take out first. Home Assistant labels each integration with an IoT class, and you want a local one on both the sensor side and the valve side. Local Push is the usual label; ZHA is labeled Local Polling, but its Zigbee sensor reports still arrive on their own over your coordinator, with no cloud in the path.

Diagram of Z-Wave, Zigbee and Shelly leak sensors reaching Home Assistant locally, which closes the Zooz or Aqara valve, with YoLink and Moen behind vendor clouds
Z-Wave, Zigbee and Shelly sensors reach Home Assistant over local connections, and Home Assistant closes the Zooz or Aqara valve without leaving the house. YoLink and Moen reach Home Assistant only through their clouds.

Two of the valves add a second safety net that does not need Home Assistant at all. The Zooz Titan has a wired probe port that closes the valve on its own. A YoLink leak sensor paired directly to the YoLink valve controller keeps working offline once both are set up. We’d still run the main logic in Home Assistant, because that is the only place one Zigbee sensor in the attic can close a Z-Wave valve in the basement, but a device-level fallback is worth having when the Home Assistant box itself is the thing that’s down.

Your radio choice follows from the controller you already run. A Z-Wave home starts with a stick from our Z-Wave 800 stick roundup. A Zigbee home needs a coordinator from the Zigbee coordinator guide and a choice between ZHA and Zigbee2MQTT, which matters here because the Aqara valve is documented for Zigbee2MQTT.

Check valves and sensors side by side

The valve table puts the install type first, because a clamp-on actuator is a ten-minute job on a ball valve you already have, while an inline valve means cutting the main line. Read the “Offline” column as “does the shutoff still fire with no internet”:

ValveInstallRadio and HA pathPowerOfflinePrice band
Zooz ZAC36 TitanClamp-on, 0.5 to 1.25 in ball valveZ-Wave, Z-Wave JS (Local Push)AC adapter, optional batteryYes, plus wired probeabout $170 to $200
Aqara Valve Controller T1Clamp-on, 1/2 to 1 inZigbee, Zigbee2MQTT4x AA, up to 2 yearsYesabout $70
YoLink Valve Controller 2 + EVOBolts to 1/2 to 2 in ball valveLoRa hub, YoLink (Cloud Push)4x AA or adapter; EVO 12 V DCOnly YoLink sensor to valveabout $240 to $270
Moen Flo Smart Water ShutoffInline, pipe cutWi-Fi, Flo (Cloud Polling)AC outlet within 10 ftMoen’s own logic; HA control needs internetabout $560 to $1,000

For the sensors, the columns that change the buying decision are whether the unit can sound an alarm on its own, how wet the place is where it lives, and what battery you’ll be hunting for in three years:

SensorRadioSirenBatteryRatingPrice band
ThirdReality 3RWS18BZZigbee120 dB2x AAA, up to 3 yearsnot publishedabout $21
SONOFF SNZB-05PZigbeeNoCR2477, 5 yearsIP67about $23
Aqara SJCGQ11LMZigbeeNo (hub sounds it)CR2032IP67about $18
Shelly Flood Gen4Wi-Fi, Zigbee or MatterBuzzer4x AA, about 2 yearsIP44about $40
Zooz ZSE42Z-Wave 800 LRNoCR2032splash-proofabout $26

Battery life figures are the makers’ own ratings. Aqara and Zooz do not publish one for these two models, which is why those cells only name the cell type.

Close the main with the Zooz Titan

The Titan is the valve we’d put on a main line first, because it’s the only pick where the sensor, the decision and the motor can all stay local and where the valve still has a fallback of its own:

Zooz ZAC36 Titan Z-Wave water valve actuator for Home Assistant automatic water shutoff
Zooz ZAC36 Titan: clamp-on Z-Wave actuator for 0.5 to 1.25 in ball valves, 6 N·m of torque. Image: Zooz.

It clamps onto an existing quarter-turn ball valve from 0.5 to 1.25 in and turns the lever with 6 N·m of torque. Zooz puts a normal valve at 1.5 to 3.5 N·m and a stiff one at 5 to 6. That is headroom for an old valve but not unlimited headroom, which is why the drill at the end of this guide matters. The radio is Z-Wave 700 series; the current hardware revision supports Z-Wave Long Range and S2 Authenticated security, US frequency only. Power comes from an AC adapter on a 9.5 ft cord, and a separate backup battery (about $50) keeps it working through an outage. Without the battery it holds its last position when power drops, which means it will not close on its own during an outage.

The detail that sets it apart is the wired leak probe on a 4.75 ft lead. Put it on the floor under the valve or the water heater and the Titan closes itself when the probe gets wet, with no hub involved. It does not reopen when the probe dries; you press the button or open it from Home Assistant, which is the behavior you want after a leak. The housing is IP66, it carries a temperature sensor and an 85 dB sounder, and it only does full open or full close.

In Home Assistant it joins through Z-Wave JS, which is Local Push. Z-Wave JS has no valve platform, so the Titan’s open and close lands as a switch entity. The automation section shows how to turn that into a proper valve entity. Check the space first: Zooz asks for 3 in of clearance each side of the valve’s center, 1 in between pipe and wall, and 1.25 in between the handle and the pipe, and the fork takes a stem nut up to 18 mm.

  • Buy it if: you run Z-Wave, have a lever ball valve on the main, and want the shutoff to survive both an internet outage and a dead Home Assistant box.
  • Skip it if: your main is a gate valve with a round wheel handle, the valve sits in a tight wall cavity, or you cannot wait for stock.

Stock is the thing to check. The Amazon listing was waiting on inventory when we looked on October 27, 2026, so the link above goes to The Smartest House, Zooz’s US store, where it listed at about $170 with a restock notice dated October 23.

Add the Aqara T1 as a Zigbee valve

The Aqara T1 costs about a third of the Titan and needs no outlet near the valve, which is often the deciding factor in a crawlspace or under a sink:

Aqara Valve Controller T1 Zigbee water shutoff valve actuator for Home Assistant
Aqara Valve Controller T1 (VC-X01D): Zigbee 3.0, four AA batteries, lever or butterfly handles from 1/2 to 1 in. Image: Aqara.

It is a clamp-on actuator for lever or butterfly handles on DN15, DN20 and DN25 valves (1/2, 3/4 and 1 in), running on four AA batteries that Aqara rates for up to two years. The radio is Zigbee 3.0. The Amazon title says “Matter Over Bridge”, which means Matter only through an Aqara Zigbee hub; with Home Assistant you can skip the Aqara hub and pair it straight to your own coordinator. The Zigbee2MQTT device page lists it as VC-X01D and exposes the valve state and battery level, so it shows up as a switch you can convert to a valve.

Two limits to plan around. Aqara’s spec sheet gives no water-ingress rating, so a valve in a wet pit or outside the house is the wrong job for it. For a line that does live outside, the Sonoff Hydro ONE puts a Zigbee valve with a built-in flow meter on the garden tap, and our guide to irrigation controllers for Home Assistant covers it next to the local and cloud watering controllers. We also could not confirm ZHA support, so if you run ZHA instead of Zigbee2MQTT, treat it as unknown until you’ve seen it pair. Aqara’s spec sheet rates the motor at up to 3.6 N·m with a 5 to 20 second travel time. That sits right at the top of Zooz’s 1.5 to 3.5 N·m range for a normal valve, so a stiff old valve is a real risk with this battery-powered motor.

Buy it if you run Zigbee2MQTT and want a shutoff for well under $100. Skip it if the valve is outdoors, if you’re on ZHA, or if the lever takes real effort to turn by hand. The Aqara T1 is about $70 on Amazon and was in stock when we checked; check the live price.

YoLink solves a problem the Zigbee and Z-Wave valves can’t: a main shutoff at the far end of a property, in a garage or meter pit hundreds of feet from the nearest mesh node. Its LoRa radio is rated up to 2,034 ft. The price for that reach is that Home Assistant talks to it through YoLink’s cloud:

YoLink Valve Controller 2 for the YoLink automatic water shutoff kit
YoLink Valve Controller 2 (shown alone; the kit adds the EVO operator, a hub and three leak sensors). Image: YoSmart.

The kit pairs the Valve Controller 2 with the EVO operator, which bolts onto an existing ball valve from 1/2 to 2 in after you remove the handle, and has a clutch for turning it by hand. The EVO runs on 12 V DC and is IP65; the controller takes four AA batteries or a plug-in adapter. A YoLink hub is required. The YoLink integration is Cloud Push and needs internet access, so a Zigbee sensor in your kitchen can only close this valve while YoLink’s servers answer.

What keeps it on the list is YoLink’s device-to-device pairing: a YoLink leak sensor linked directly to the controller still closes the valve with no internet once both are set up and powered. So the honest way to run it is YoLink sensors next to the risky fixtures for the offline shutoff, and Home Assistant for alerts and everything else. Buy it for a long run your mesh cannot cover. Skip it if you want every part of the chain local. The full kit with hub and three sensors is about $270 on Amazon. If you already own a YoLink hub, YoSmart’s own store sells the controller and EVO without a hub for about $240.

Cut in a Moen Flo inline valve

The Moen Flo is a different class of device. It goes inline on the main cold line after the meter, the main shutoff and any pressure regulator, so the pipe gets cut and Moen recommends a plumber:

Moen Flo Smart Water Shutoff inline automatic water shutoff valve
Moen Flo Smart Water Shutoff: inline valve with flow and pressure monitoring, sold in 3/4, 1 and 1-1/4 in sizes. Image: Moen.

In return it sees the whole house’s water use, not only the spots where you placed a probe. Its daily MicroLeak tests are meant to catch a dripping toilet flapper or a pinhole in a wall that no floor sensor would ever touch. It needs 2.4 GHz Wi-Fi and an AC outlet within 10 ft, and Moen says it keeps protecting the house when Wi-Fi drops. The app is free; the optional Leak Protection Service is a paid plan with a 36-month commitment.

Home Assistant can drive it, but only through Moen. The Flo integration is Cloud Polling and gives you a switch that opens and closes the valve, plus actions for a health test and the home, away and sleep modes. A Zigbee sensor in your kitchen can therefore close the Flo only while the internet and Moen’s servers are up, so Moen’s own leak logic stays the real offline shutoff. Buy it if slow hidden leaks worry you more than a burst hose. Skip it if you want every hop between sensor and valve to stay inside the house. The 3/4 in model is about $560, the 1 in model about $610, before the plumber.

Add a siren with ThirdReality

Most Zigbee leak sensors are silent and leave the alarm to the hub, which is a problem when the hub is Home Assistant and nobody is looking at a phone. The ThirdReality 3RWS18BZ has a 120 dB siren built in, so whoever is home hears the leak even if the valve automation never runs:

ThirdReality Zigbee water leak sensor with siren for Home Assistant
ThirdReality Zigbee Water Leak Sensor (3RWS18BZ): 120 dB siren, two AAA cells rated for up to three years. Image: ThirdReality.

It runs on two AAA batteries, included, that ThirdReality rates for up to three years, and pairs with ZHA or Zigbee2MQTT. Zigbee2MQTT exposes a buzzer switch and the alarm duration, so you can silence it from Home Assistant once someone has dealt with the water. It is about $21 for one on Amazon, or about $80 for a four-pack, which covers the kitchen, the bathrooms and the water heater in a typical house.

Skip it where the sensor will sit in standing water or outdoors: ThirdReality doesn’t publish an IP rating for this model, and the SONOFF below is the better fit there. Its newer WL2 sibling is IP65 but drops the siren, which removes the reason to pick ThirdReality in the first place.

Place a SONOFF SNZB-05P in wet spots

The SNZB-05P is the sensor for the places that get wet on purpose: a sump pit edge, the floor by a washing machine drain, under a water softener. It’s IP67 rated, triggers at 0.5 mm of water, and runs on a CR2477 coin cell that SONOFF rates for five years:

SONOFF SNZB-05P Zigbee water leak sensor IP67 for Home Assistant
SONOFF SNZB-05P: Zigbee leak sensor, IP67, CR2477 coin cell rated for five years. Image: SONOFF.

On firmware 1.0.2 or later it repeats the leak report every 10 minutes while it stays wet, which helps when the first message was lost on a busy mesh. An extension cable attaches with a magnetic clip for reaching under an appliance. SONOFF sells the cable separately or in kits; the Amazon listing we link is titled “with Detection Cable”, but confirm the cable is in the box on the listing before you count on it. It works with ZHA and Zigbee2MQTT.

There is no siren, so pair it with a Home Assistant notification or a ThirdReality nearby if you want something audible. The SNZB-05P is about $23.

Put Aqara sensors under every sink

The Aqara SJCGQ11LM is the sensor to buy in quantity. It is small, IP67, triggers at 0.5 mm and costs about $18 for one or about $43 for a three-pack:

Aqara Zigbee water leak sensor SJCGQ11LM for Home Assistant
Aqara Water Leak Sensor (SJCGQ11LM): Zigbee, IP67, CR2032 coin cell. Image: Aqara.

The Amazon title says an Aqara hub is required, but that is only for Aqara’s app and the hub’s alarm. With Home Assistant it pairs to any coordinator through ZHA or Zigbee2MQTT and reports leak, battery and device temperature. The sensor itself has no siren.

Aqara end devices are picky about which Zigbee routers they join through. Zigbee2MQTT’s device page reports this one pairing fine through Hue bulbs and a Sengled plug and failing through an older SONOFF ZBMINI, so pair it close to the coordinator or a router known to work. Skip it if your mesh is mostly no-name routers you can’t swap out.

Skip the coordinator with Shelly

If you don’t run Zigbee or Z-Wave at all, the Shelly Flood Gen4 talks to Home Assistant over your Wi-Fi through the Shelly integration, which is Local Push:

Shelly Flood Gen4 Wi-Fi and Matter water leak sensor with sensing cable
Shelly Flood Gen4 (S4SN-0071A): Wi-Fi, Bluetooth, Zigbee and Matter, 2 m sensing cable extendable to 150 m. Image: Shelly.

The sensing cable is the reason to pick it. It ships with 2 m of cable that extends to 150 m. One sensor can follow the whole length of a basement wall or loop around a water heater, where a puck only covers the spot it sits on. It runs on four AA batteries rated for about two years, has a buzzer, and ships on Matter firmware; five presses of the button switch it to Zigbee if you would rather put it on your mesh. Shelly rates it IP44, so keep the body itself out of standing water.

It’s about $40 on Amazon. For a cheaper point sensor in the same family, the Shelly Flood S Gen4 is about $28, IP67, runs on an included CR123A, and uses stainless pads that Shelly says detect low-conductivity water. Skip both on a weak 2.4 GHz network, because a Wi-Fi sensor in a basement is only as good as the signal down there.

Cover a Z-Wave house with Zooz ZSE42

If the Titan is your valve, the ZSE42 keeps the whole leak system on one radio. It is an 800 series Z-Wave sensor with Long Range support, 0.3 in thick, and runs on a single CR2032:

Zooz ZSE42 Z-Wave Long Range water leak sensor for Home Assistant
Zooz ZSE42 XS Water Leak Sensor: Z-Wave 800 series with Long Range, CR2032 coin cell. Image: Zooz.

Z-Wave Long Range talks straight to the stick in a star layout, which suits a sensor at the far end of a basement where a Zigbee mesh would need a router nearby. The ZSE42 supports SmartStart and S2 and joins through Z-Wave JS as Local Push. It’s splash-proof rather than submersible, with no siren and no remote probe, so it’s a sensor for the floor under a sink, not for a pit.

We found no Amazon listing for it, so the link goes to The Smartest House, where it was about $26 and in stock when we checked. Skip it if you’re on Zigbee; the Aqara and SONOFF sensors do the same job for less.

Wire the leak automation in Home Assistant

You do not want the first real test of a shutoff automation to be a real leak. So we built the chain in a Home Assistant 2026.10.4 container on an Ubuntu 26.04 VM with stand-in entities. Two input booleans play the probe contacts, template moisture sensors play the leak sensors, and a template switch plays the valve relay. That’s the same shape the real hardware takes, because both the Zooz Titan and the Aqara T1 land in Home Assistant as switches. Swap the entity IDs for yours once the devices are paired, or keep the stand-ins around for rehearsing changes.

The stand-ins live in configuration.yaml in the folder you bind-mounted at /config. That’s ~/ha-config in our lab and /opt/homeassistant/config if you followed our Ubuntu install guide, so adjust the path. Open it:

sudo vim ~/ha-config/configuration.yaml

A default configuration.yaml already includes automations.yaml, so add only these two blocks, exactly as they ran in the lab. If you already have an input_boolean: or template: key from another setup, merge these entries into it instead of adding a second key. The initial: true on the relay boolean starts the stand-in valve open after every restart:

input_boolean:
  leak_kitchen_sink_probe:
    name: Kitchen sink probe contact
  leak_water_heater_probe:
    name: Water heater probe contact
  main_valve_open:
    name: Main valve relay
    initial: true

template:
  - binary_sensor:
      - name: Kitchen sink leak
        unique_id: leak_kitchen_sink
        device_class: moisture
        state: "{{ is_state('input_boolean.leak_kitchen_sink_probe', 'on') }}"
      - name: Water heater leak
        unique_id: leak_water_heater
        device_class: moisture
        state: "{{ is_state('input_boolean.leak_water_heater_probe', 'on') }}"
  - switch:
      - name: Main water valve relay
        unique_id: main_water_valve_relay
        state: "{{ is_state('input_boolean.main_valve_open', 'on') }}"
        turn_on:
          action: input_boolean.turn_on
          target:
            entity_id: input_boolean.main_valve_open
        turn_off:
          action: input_boolean.turn_off
          target:
            entity_id: input_boolean.main_valve_open

Now the automation itself. Open automations.yaml:

sudo vim ~/ha-config/automations.yaml

On a fresh install the file holds only []; replace that line with the block below, or append the block under existing entries if the UI has already written automations. One state trigger lists every moisture sensor, so adding a sensor later means adding one line. The notification names whichever sensor fired, which tells you where to look before you open the valve again. A persistent notification only shows in the Home Assistant UI, so add a notify action for your phone in a real install:

- id: leak_close_main_water_valve
  alias: "Leak: close main water valve"
  mode: single
  triggers:
    - trigger: state
      entity_id:
        - binary_sensor.kitchen_sink_leak
        - binary_sensor.water_heater_leak
      to: "on"
  actions:
    - action: valve.close_valve
      target:
        entity_id: valve.main_water_valve_relay
    - action: persistent_notification.create
      data:
        title: Water leak
        message: "{{ trigger.to_state.name }} is wet. Main water valve closed."

Validate the config before restarting. On a container install that’s the check_config script (on Home Assistant OS, use Settings, Tools, YAML, Check configuration); plain output only prints the path, so ask for the automation section to get an explicit result:

sudo docker exec homeassistant python -m homeassistant --script check_config -c /config --info automation

The first two lines are the ones to look for. A bad indent or a malformed key turns them into an error with the file and line number. It does not check that the valve entity exists, though: the lab’s first pass targeted a valve name that was never created and still passed, which is why the helper steps below end with confirming the real entity ID:

Testing configuration at /config
Successful config (partial)

The new input booleans and template entities only exist after a restart, and the helper below cannot find a switch that isn’t there yet. Restart the container:

sudo docker restart homeassistant

There’s no template valve in this release, so the valve entity comes from the helper Home Assistant uses for exactly this case: Change device type of a switch. The same steps convert a real Titan or Aqara T1 switch:

  1. Open Settings, then Devices & services, then the Helpers tab, and choose Create helper.
  2. Pick Change device type of a switch and select the valve’s switch entity (here switch.main_water_valve_relay).
  3. Set the new type to Valve and leave invert off, so “on” stays “open”. On a real Titan, check its “Invert Water Valve Report” setting first, because changing it flips that meaning.
  4. Note the new entity ID. Ours came out as valve.main_water_valve_relay, not the shorter name we’d planned. If yours differs, fix the target in automations.yaml and reload automations from Settings, Tools, YAML.
  5. Test the chain: open Settings, Devices & services, Entities, search for input_boolean.leak_water_heater_probe and turn it on from its dialog, confirm the valve entity shows closed, then open the valve and turn the probe back off. On real hardware, confirm after pairing that the switch’s “on” really means open before you trust the conversion.

This is the check_config run from the lab terminal, with the Home Assistant version and the automation file that ran:

Home Assistant check_config passing and the leak automation that closes the main water valve
Home Assistant 2026.10.4: check_config passes and the leak automation targets the converted valve entity.

Then we cut the internet. Deleting the VM’s default route kept the LAN up and the WAN gone, so curl to Google failed straight away. Flipping the water heater probe on still closed the valve: the sensor changed state at 03:58:54.183140 and the valve at 03:58:54.184292, about 1 ms apart, against 3 ms on the earlier run with the internet up. Measured separately after 30 seconds idle, the container sat at 0.08% CPU and about 309 MiB of RAM.

Home Assistant closing the water shutoff valve 1 ms after a leak sensor trips with the internet cut
With the default route deleted, curl fails, and the valve still closes 1 ms after the water heater sensor goes wet.

Read those numbers for what they are. A millisecond is the decision time inside Home Assistant; a real motorized valve then takes seconds to travel, and a battery Zigbee sensor adds its own reporting delay. What the test proves is that nothing in the chain waits on the internet, which is the part a cloud integration can’t promise.

Check the plumbing first

The valve decides whether an actuator fits at all, long before the radio matters. Walk to your main shutoff with a tape measure before you order, and check these in order:

  1. Confirm it’s a quarter-turn ball valve with a lever. A round wheel handle is a gate valve, and none of the clamp-on actuators here turn one; that means an inline valve like the Moen or a plumber swapping in a ball valve.
  2. Measure the pipe size and compare it to the actuator: 0.5 to 1.25 in for the Titan, 1/2 to 1 in for the Aqara T1, 1/2 to 2 in for the YoLink EVO.
  3. Turn the lever fully closed and open by hand. If it needs a wrench, it may beat a battery motor, and a seized valve is a plumber job before any actuator goes on.
  4. Measure the clearance around the valve and to the wall; the Titan’s numbers are in its section, and the others need similar space for the clamp and motor.
  5. Find the power. A mains actuator needs an outlet in reach and, ideally, a backup battery; a battery actuator needs you to watch its battery entity.

Then place sensors where water shows up first, not where it is convenient: the lowest point under each sink, the drip pan of the water heater, behind the washing machine, beside the dishwasher and the fridge’s water line, and next to the main valve itself. Coin-cell pucks are cheap enough that one per fixture beats one big sensor in the middle of the room.

Matter is the protocol to watch. Home Assistant’s Matter integration has had valve entities since 2024.10 and maps Matter water leak detectors to moisture sensors, so a Matter valve and sensors would work locally with no stick at all. The catch today is the hardware: of the valves we could buy and verify, the only Matter path is Aqara’s, and that runs through an Aqara hub as a bridge.

Keep these off the shortlist

A few names come up in every leak thread and still didn’t make the picks, for reasons that have nothing to do with how well they sense water:

  • Eve Water Guard: a good Thread sensor with a 2 m sensing cable and a 100 dB siren that pairs locally through HomeKit Device, but Amazon and Eve’s own store both showed it out of stock.
  • SwitchBot Water Leak Detector: Home Assistant’s SwitchBot Bluetooth integration supports a leak detector locally, but we could not match the Wi-Fi models on Amazon to the one it supports.
  • YoLink leak sensors on their own: fine next to a YoLink valve, but in Home Assistant they’re Cloud Push like the valve.
  • Govee leak sensors: cloud only, so they cannot trigger a local shutoff.
  • ThirdReality KM1 Matter kit: announced in March 2026 and tested with Home Assistant by the maker, but we found no Amazon listing to check.

Any of these could earn a place once stock or support settles. Until then the picks above cover every radio without a gap.

Run a monthly valve drill

A shutoff valve that sits open for a year can stiffen until the actuator can’t move it, and that’s the failure you only find during a leak. So we’d put the whole chain through a drill once a month, on a morning when nobody is in the shower. Home Assistant can schedule the valve part of it, and the rest takes five minutes:

  1. Close the valve from Home Assistant, open a tap and confirm the flow stops, then open the valve again.
  2. Wet one leak sensor with a damp cloth and confirm the automation closes the valve and the notification names the right sensor.
  3. Check the battery entity of every sensor and the Aqara T1, and replace anything low before winter.
  4. On a Titan, wet its wired probe once a quarter too, because that path does not show up in Home Assistant’s traces.

Two additions make the drill less necessary. A second automation that alerts you when the valve or any leak sensor goes unavailable catches a dead battery or a dropped mesh node before it matters. And the box running Home Assistant belongs on a UPS, because a mains-powered valve and its controller are only as available as the power behind them; if you’re still choosing that box, our mini PC guide for Home Assistant covers the low-power options, and the Ubuntu 26.04 install guide covers a Docker Compose install of the same container image. For the Zigbee side, our ZHA vs Zigbee2MQTT comparison helps you choose the stack the Aqara valve needs.

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