Water Protection:
Set Up Right the First Time

The Three Layers of Water Protection

Why sensors alone aren't enough

A leak sensor under your kitchen sink tells you there's water on the floor. By the time that alert reaches your phone — especially if you're away — water has been flowing for minutes. The sensor did its job. But without something downstream that acts on that information, the sensor is just a notification device.

The goal of a whole-house water protection system is to close the gap between detection and action. The faster water is stopped, the less damage occurs. For a slow drip under a sink, minutes matter. For a washing machine supply line failure — which can discharge 600+ gallons per hour — seconds matter.

Layer 1: Point sensors (Eve Water Guard)

Point sensors sit at specific risk locations: under sinks, behind appliances, near water heaters, and around HVAC equipment. They detect water contact immediately — before any visible pooling or spread. Eve Water Guard uses a long probe cable rather than a single-point puck, which makes it better at catching water that approaches from an angle or at the edge of a drain pan.

Layer 2: Whole-home flow monitoring (Moen Flo)

The Moen Flo Smart Water Shutoff installs on your main water supply line and monitors every drop of water flowing through your house. It learns your usage patterns and flags anomalies: a toilet running too long, a slow drip behind a wall, an unusually high flow rate at 3am. This layer catches leaks that no point sensor would reach — inside walls, underground supply lines, slow slab leaks.

Layer 3: Automatic shutoff

The Moen Flo can shut off automatically based on its own detection rules. It also exposes a HomeKit valve accessory, which means Apple Home automations can close it in response to any other HomeKit event — including an Eve Water Guard detecting a leak. That automation — sensor detects water, shutoff closes — is what converts a notification system into a prevention system.

Setting Up Eve Water Guard

Thread connectivity and what it requires

Eve Water Guard connects via Thread — the low-power mesh protocol built into Apple HomePod, Apple TV 4K, and eero routers (Pro 7 and Max 7). Thread devices respond instantly to automations even when your internet is down, and they run for about 3 years on a single CR2 battery. If you have eero nodes, HomePods, or an Apple TV 4K, Thread is already available and Eve Water Guard will connect to it automatically.

Physical setup

Eve Water Guard consists of a sensor body and a 2-meter probe cable. The sensor body mounts in a dry, accessible spot — on a cabinet wall, a pipe, or an appliance side. The probe cable runs into the risk area. The tip of the cable should lie flat at the lowest point where water would first pool.

For under-sink placement: mount the sensor body inside the cabinet, run the probe cable toward the back where supply line drips land. For HVAC drain pans: mount the sensor on the side of the air handler, run the probe into the drain pan. Extended 5-meter cables are available separately for tight or deep placements.

Adding to Apple Home

Eve app → tap + → Add Accessory → scan the HomeKit code on the back of the sensor. Assign it to a room and name it by location — "Under Kitchen Sink," "HVAC Unit 1," not just "Water Guard." With multiple sensors, specific names are the difference between knowing immediately where to go and wasting minutes in an emergency.

The sensor appears in Apple Home as a Leak Sensor. Test it by touching two fingers to the probe tip — it triggers within seconds and Apple Home shows "Leak Detected." Thread connectivity activates automatically; confirm it's connected via Thread (not just Bluetooth) in the Eve app device details before relying on remote alerts.

Where to place sensors

Full coverage means: under every sink, washing machine, dishwasher, refrigerator (if it has a water line), water heater, and every HVAC condensate drain pan. The HVAC pans are the most important placement most people skip — an overflowing attic air handler can cause thousands in ceiling damage before it's visible from below.

The Automation That Makes It Work

What it does

When any Eve Water Guard detects water, Apple Home automatically closes the Moen Flo's main shutoff valve. Water to the house stops within seconds — before you've seen the notification, before you've had a chance to react. This is what the sensors are for. The notification tells you what happened; the automation stops the damage.

Building it in Apple Home

Home app → Automations tab → + → "An Accessory is Controlled" → select your Eve Water Guard sensor → trigger: "Leak Detected" → Action: select Moen Flo → "Close." Optionally add a notification action so you know the shutoff fired. Repeat for each sensor — Apple Home requires one automation per trigger device.

The automation intentionally doesn't re-open the Flo automatically when the sensor clears. A real leak needs a human to confirm the source before restoring water. To test it: trigger a sensor with your fingers, watch the Flo close in the app, then manually re-open it. One test run gives you confidence the whole chain works.

What's next

This covers the foundation. The full guide goes deeper across 11 chapters: Eve Water Guard placement strategy for every location including HVAC drain pans; Apple Home notification configuration for 12+ sensors; Eve Aqua setup and outdoor watering schedules; Moen Flo installation and Health Test monitoring; Flo app automations as a parallel shutoff path independent of Apple Home; and the complete 3-layer, 15-sensor setup with what I'd do differently.