IoT Water Leak Detector with Auto Shutoff and Multi-Zone Alerts

A slow leak under a kitchen sink or behind a washing machine can run for weeks unnoticed, rotting cabinets, seeping into walls and wasting thousands of litres — and the first sign is often a stained ceiling in the flat below. Standalone leak alarms exist but only beep locally, useless in an empty house. This project builds the complete response chain: conductive probes in up to four zones detect water the moment it bridges their contacts, an ESP32 judges the event, a buzzer alarms locally, a solenoid valve shuts the water line automatically to stop the damage at its source, and Wi-Fi telemetry pushes the zone name to the owner's phone and a cloud event log. Battery backup keeps protection alive through power cuts, which is exactly when unattended leaks do their worst.

1. Conductive probes are placed at floor level in up to four leak-prone zones and wired back to the ESP32 node.
2. The firmware scans each probe continuously; water bridging a probe's contacts pulls its reading past the wet threshold.
3. A detection must persist for the configured confirmation time (design: ~5 s) to filter out splashes and mopping.
4. On confirmation the node sounds the buzzer, lights the zone LED, and energizes the solenoid valve to close the water line.
5. The event — zone name, timestamp, valve state — publishes over Wi-Fi to the cloud dashboard and triggers a phone push alert.
6. The dashboard event log records every detection and valve action; the on-device display shows the wet zone until acknowledged.
7. The owner inspects the zone, presses the acknowledge/reset button, and the valve re-opens only on manual reset.

Tech stack:

• ESP32 development board (Wi-Fi)
• Conductive water-leak probes x4 (zones)
• 12 V normally-open solenoid valve + driver
• Buzzer + zone indicator LEDs
• 0.96-inch OLED / 16x2 LCD zone display
• Rechargeable battery backup pack
• Cloud dashboard + push alerts (Blynk/ThingSpeak class)
• Arduino IDE (C/C++ firmware)

• [Multi-zone probe sensing] Up to four conductive water probes (under sink, washing machine, geyser, tank outlet) are scanned continuously; each zone is named in firmware so alerts identify exactly where the water is.
• [Automatic shutoff valve] On a confirmed detection the ESP32 drives a normally-open solenoid valve on the water line closed, stopping the inflow at its source without human intervention.
• [Local alarm] A loud buzzer plus a zone LED panel at the node alarms immediately for anyone at home, even if the internet is down.
• [Phone and cloud alerts] The zone name, timestamp and valve state publish over Wi-Fi; the owner gets a push alert and the dashboard keeps a timestamped event log.
• [Battery backup] A rechargeable pack keeps sensing, alarm and valve drive alive during mains power cuts (design target: several hours of protection).
• [False-alarm filtering] Firmware requires the probe to stay wet for a configurable confirmation time, so a mopped floor or a splash does not shut the house water off.
• [On-device zone display] A small LCD/OLED shows each zone's DRY/WET status at a glance for installation checks and demos.

• ESP32 leak-detector node with 4 zone inputs and zone display
• 4 conductive water probes with cabling
• Solenoid shutoff valve with driver circuit
• Buzzer, zone LEDs and battery backup pack
• Firmware with confirmation filtering and Wi-Fi telemetry
• Cloud dashboard + alert setup guide
• Project report PDF (sensing principle, valve sizing, methodology)
• PPT presentation for final review
• Viva Q&A preparation document (conductive sensing, solenoid drive, IoT alerting)

• Probes detect water that reaches them — placement at the lowest point of each zone matters; water pooling elsewhere in the room is not sensed.
• The solenoid valve must be sized to the home's pipe diameter and pressure; the included guide covers selection but the valve is matched at build time.
• The valve closes the monitored line only; leaks from sources upstream of the valve or from drainage are outside its control.
• Battery backup covers hours, not days — extended outages need a larger pack (listed as an option).
• Push alerts need working Wi-Fi and internet; the local buzzer and valve work regardless.