When it comes to protecting your tankless water heater, a leak detection alarm with automatic shutoff is a must-have. It’s like an insurance policy against the catastrophic damage that water leaks can cause, especially since tankless water heaters often rely on high-pressure water systems. Fortunately, there are several high-quality leak detection systems designed to shut off the water supply as soon as a leak is detected. Here are some of the best options available:
1. Flo by Moen Smart Water Shutoff – Best Overall
Flo by Moen is widely regarded as one of the most comprehensive and reliable smart leak detection systems on the market. This device not only detects leaks but also monitors water pressure and flow to help prevent leaks from ever occurring. Once a leak is detected, it automatically shuts off the water supply to prevent further damage. It’s compatible with tankless water heaters and can be installed on your main water line for complete home protection.
Key Features:
- Smart leak detection and auto shutoff
- Real-time monitoring of water pressure, flow, and temperature
- App notifications and remote shutoff via your smartphone
- Integrates with Alexa and Google Assistant
- Can detect micro-leaks as small as one drop per minute
Pros:
- Comprehensive system for whole-house protection, including your water heater
- Automatically shuts off the main water line in case of a leak
- Continuous water monitoring for early leak detection
- Easy to control remotely via a smartphone app
Cons:
- Requires professional installation on the main water line
- More expensive than other basic leak detection systems
2. LeakSmart Water Leak Detection System – Best for Quick Response
The LeakSmart system is another great option for protecting your tankless water heater. It’s designed to detect leaks in under 5 seconds and automatically shut off the water supply to prevent flooding. The system is wireless, allowing for easy installation near your water heater or any other high-risk areas. It’s highly responsive and can be integrated into your smart home system.
Key Features:
- Shuts off water within 5 seconds of detecting a leak
- Wireless sensors for easy placement near water heaters, washing machines, etc.
- Battery backup so the system works even during power outages
- Smart home integration with systems like Alexa, Google Assistant, and Samsung SmartThings
- Sends real-time alerts via the app
Pros:
- Fast response time with automatic shutoff
- Wireless sensors can be placed anywhere
- Compatible with tankless water heaters and other appliances
- Battery backup ensures protection even in power outages
Cons:
- The system is a bit pricey compared to simpler sensors
- Requires a hub for full smart home integration
3. Honeywell Home Water Leak and Freeze Detector – Best Budget Option
If you’re looking for a more budget-friendly option without sacrificing effectiveness, the Honeywell Home Water Leak and Freeze Detector is an excellent choice. While it doesn’t offer automatic shutoff, it provides instant alerts via an app when a leak is detected. It’s a simple, straightforward system that’s perfect for smaller setups, including near a tankless water heater. You can add multiple sensors to cover more areas around the heater.
Key Features:
- Detects leaks and temperature drops to prevent freezing
- Sends alerts to your phone or email in case of a leak
- Can be placed near the water heater or other appliances
- Battery-operated for easy installation
Pros:
- Affordable and easy to install
- Sends instant leak alerts to your phone
- Monitors for freezing conditions, making it great for colder climates
Cons:
- Does not have an automatic shutoff valve
- Requires manual intervention to turn off the water
4. Phyn Plus Smart Water Assistant + Shutoff – Best for Water Conservation
The Phyn Plus is another premium option that combines leak detection, automatic shutoff, and water usage monitoring. It connects to your main water line and provides whole-home protection, including for your tankless water heater. Phyn uses patented pressure wave analysis to detect leaks and water usage patterns, allowing it to catch even the smallest leaks early on. Like the Flo by Moen, it offers remote control and monitoring via a smartphone app.
Key Features:
- Automatic water shutoff for leaks
- Water usage monitoring to help conserve water
- App alerts you to leaks and allows remote shutoff
- Real-time diagnostics of your plumbing system
- Integrates with Alexa and Google Assistant
Pros:
- Detects even tiny leaks using advanced technology
- Whole-home protection with automatic shutoff
- Helps you save water by identifying wasteful usage patterns
- Easy to monitor and control from anywhere with a smartphone
Cons:
- Requires professional installation
- Higher price point, but offers advanced features
5. Guardian Leak Prevention System by Elexa – Best for DIY Installation
The Guardian Leak Prevention System is perfect for those who prefer to install a system themselves without needing a plumber. It comes with wireless leak detectors and a motorized shutoff valve that you can easily install on your water line. This system is ideal for protecting your tankless water heater as the wireless sensors can be placed around the heater to detect leaks immediately. The Guardian system doesn’t require Wi-Fi to function but offers app integration for remote monitoring and control.
Key Features:
- Automatic shutoff valve that installs on your existing water line
- Wireless sensors for easy placement near water heaters, sinks, etc.
- No Wi-Fi needed to operate the system (Wi-Fi only required for app)
- App-based monitoring and control from anywhere
- Easy DIY installation with no professional help needed
Pros:
- DIY-friendly installation with no need for a plumber
- Wireless leak sensors that can be placed throughout the home
- Automatic water shutoff when leaks are detected
- No Wi-Fi needed for the system to function
Cons:
- App features limited compared to higher-end systems
- Not as advanced in water pressure or usage monitoring
Which System Is Right for You?
Choosing the right leak detection and shutoff system depends on your budget, the complexity of your plumbing system, and how much protection you need. Here’s a quick summary of the top choices:
| System | Best For | Shutoff Time | Smart Features | Price Range |
|---|---|---|---|---|
| Flo by Moen | Whole-home monitoring & protection | Immediate | Smart app, water usage monitoring | $$$ |
| LeakSmart | Fast response in under 5 seconds | < 5 seconds | Wireless sensors, app integration | $$$ |
| Honeywell Leak Detector | Budget-friendly leak detection | No shutoff | Simple alerts via app or email | $ |
| Phyn Plus | Advanced water usage & shutoff | Immediate | Detailed water diagnostics, remote control | $$$ |
| Guardian Leak Prevention | DIY installation, simple protection | Immediate | Wireless sensors, no Wi-Fi required | $$ |
Final Thoughts: Best Protection for Your Tankless Water Heater
If you want full protection, I recommend either the Flo by Moen or LeakSmart system. They both offer immediate water shutoff in the event of a leak, smart home integration, and comprehensive water monitoring. For those on a tighter budget, the Honeywell Home Water Leak Detector is a great low-cost option that offers reliable leak alerts without the automatic shutoff.
For tankless water heaters, where leaks could lead to significant water damage, automatic shutoff is crucial.