Flood Sensor for Home
Water-Level, Leak and Power-Cut Alerts for Flood-Prone Houses

What smart sensors can and cannot do in a flood

In a flash flood, the difference between a wet floor and ruined furniture is often the half hour before anyone notices. Families in flood-prone streets know the pattern: a heavy afternoon storm, the monsoon drain fills, water backs up through the floor traps at the back, and the first person to see it is the one who comes downstairs.

Smart sensors shorten that gap. They report water at the spots where it arrives first, they tell you when the power fails, and they keep reporting while you are at work, upstairs or away. What they cannot do is hold back water, predict a river or replace the official warnings. Treat them as the house’s own early-warning layer, sitting under the public one.

Start with the official warnings

Two official sources tell you what is coming before your sensors tell you what has arrived. The JPS Public InfoBanjir site publishes the latest flood warnings and live readings from water-level and rainfall stations, with each water-level station shown as Normal, Waspada, Amaran or Bahaya. MET Malaysia issues weather warnings, including warnings for continuous rain.

Find the river or drain station nearest your house on InfoBanjir and bookmark it on every phone in the family. During the wet season, a station moving from Normal to Waspada is the moment to check that your sensors are online, not the moment water reaches the porch.

Sensor types for a flood-prone house

Most homes need only the first two plus a power-loss alert. Spot sensors are the same family as the devices on the water leak sensor guide; here they are placed for water coming from outside rather than a burst hose.

Where to put them in a landed house

• The lowest floor trap, usually in the wet kitchen, yard or downstairs bathroom, where drain water pushes up first.
• Inside the back door or kitchen door, the usual entry point when the back lane floods.
• The sump pit, if you have one, as a high-water sensor separate from the pump’s own float.
• The porch, if the car porch sits below road level, on a wall bracket just above the floor.
• The understairs store or garage, where valuables and documents are often kept low.

Mount spot sensors on the floor or a low bracket, never on a shelf where water arrives last. Keep the hub, the router and any siren upstairs or high on a wall, because a sensor that reports to a hub sitting in floodwater reports to nobody.

Stepped alerts: early, rising, act now

One sensor tells you water has arrived. Two or three at different heights tell you how fast it is coming, which is what decides whether you sweep, lift furniture or leave. A simple home ladder copies the idea of the official one:

Give each sensor a name that says the action, such as “Step 2 back door”, and send step one to the household only, with steps two and three going to every family member and a trusted neighbour.

Power-cut alerts: knowing when the electricity has gone

Floods and power cuts arrive together, either because the supply fails in the storm or because the house trips when water reaches a socket. A smart home can tell you, but only if something stays powered long enough to send the message.

• Hub with a battery: some hubs notice their own power going and send a notification before they shut down. Check the maker’s app for a power-loss setting before relying on it.
• Router and hub on a small backup supply: a plug-in smart device then drops offline when the power fails, and an offline notification for that one device becomes your power-cut alert.
• Fridge and freezer: a battery temperature sensor inside shows how long the food has been warming if the cut lasts.

Test it once: switch off a plug-in device at its socket and time how long the alert takes to arrive.

Keeping alerts alive when power and internet drop

Battery sensors keep working in a power cut; the weak link is everything between the sensor and your phone. The router, the fibre box and the hub all need power, and the fibre line may fail in a wide outage. Two fixes cover most homes: put the router and hub on a small backup supply, and choose a hub or gateway that can fall back to mobile data. The guide to smart homes in a power cut explains how to size and place that backup.

Turn on the offline notification for every flood sensor too. A sensor with a flat battery looks exactly like a dry floor in most apps.

Automations that buy time, and ones to avoid

• Sound the siren upstairs and switch on the stair and landing lights when a step two sensor trips at night.
• Send step two and three alerts to several phones, including someone who does not live in the house.
• Take a snapshot from the camera facing the front drain, so a relative at work can judge the situation.
• Run a sump or drainage pump through a smart switch, with the pump’s own float still in charge; the smart pump switch guide covers that set-up.

Avoid automations that switch sockets or appliances on downstairs once water is present, and never ask a family member to wade into water to reset a device. For smart switches and anything wired into the mains, we supply the devices and set up the app, and the switch or wiring work is done by an electrical contractor registered with Suruhanjaya Tenaga that we coordinate.

Electricity and floodwater: advice, not automation

A smart home cannot make a flooded ground floor electrically safe. If water is rising, the decision to switch off the supply belongs to a person standing on dry ground who can reach the board safely; if that is not possible, stay away from the water and leave. The flood clean-up and prevention hub explains what to check before the power goes back on.

Homes that flood every year often move sockets and the board higher during renovation. Any mains electrical work, such as a new power point, a change at the distribution board or a hardwired switch that needs new wiring, must be done by an electrical contractor registered with Suruhanjaya Tenaga.

Before the monsoon: test the whole chain

Flood sensors sit unused for months and then must work on the one night that matters. Before the wet season, run a full test:

1. Dip each spot sensor in a tray of water and confirm the right phones get the right step alert.
2. Lift the float in the sump pit by hand and confirm the high-water alert, as the sump pump guide recommends for the pump itself.
3. Switch off the router’s socket and check the hub still reports on its backup or mobile data.
4. Replace any battery the app shows as low, and clean silt off probes from the last storm.
5. Check the InfoBanjir station bookmark still opens on every phone.

How we set it up

We install battery flood sensors at the right spots and heights, set the stepped alerts and sharing, put the hub and siren where water will not reach them, and test the chain with you before the wet season. We do the smart device, app and low-voltage side of the job. For the rest of the smart home, see our smart home installation service.

Sources & references

• JPS Public InfoBanjir: official flood warnings and water-level station status.
• MET Malaysia: official weather forecasts and warnings.
• ClickBina flood preparation, flood hub and sump pump guides: the wider flood plan.