Aquarium Leak Detectors
Every other device on this site protects the tank. A leak detector protects the room — and on anything above a nano, the water in a tank is heavy enough and destructive enough that the floor under it is a genuine liability.
What the risk actually is
A 75-gallon tank holds roughly 280 liters, which is about 280 kg of water sitting on a floor that was designed for furniture. The failure modes are rarely the glass breaking: a sump overflows because a return pump siphoned back on a power cut, an auto top-off sticks on, a hose clamp lets go, or a skimmer floods overnight.
None of those are dramatic. All of them put water on the floor for hours before anyone notices, and on an upper floor that is a ceiling below.
The two useful forms
Alarm only
A probe on the floor and a loud sounder. Cheap, battery-powered, no installation. Useless if you are away — it warns whoever is in earshot.
Alarm plus notification
Adds a network connection so it reaches your phone. This is the version that matters for a tank you leave for a weekend, and it depends on power and connectivity staying up.
Some systems go further and cut power to a pump or close a valve. That is the only form that stops the leak rather than reporting it, and it introduces a device with authority over your life support — a trade worth thinking about rather than assuming.
No comparison page for this category. Weight and voltage both sit exactly at the 40% coverage gate across 30 products, and neither is a buying signal — voltage here just distinguishes a 3 V coin cell from a 9 V battery. Sensor count, alarm volume in dB, battery life and whether the unit notifies at all are the specifications that would decide a purchase, and none are published as structured attributes.
Where to put the sensor
This matters more than which detector you buy, and no specification covers it.
- On the floor at the lowest point near the stand, not on the stand itself — water runs down and pools.
- Inside the cabinet under the sump, which is where most leaks actually start.
- Not where routine splashing lands. A detector that cries wolf during a water change gets unplugged, and an unplugged detector protects nothing.
- Test it on a schedule. A battery device you installed two years ago and never checked is decoration.
A detector reports; it does not stop water. We do not test this equipment. If a flood would be serious — an upper floor, a rented property, an expensive room — the mitigation is a drip tray, a sensible sump volume and a plumbing design that cannot back-siphon, with the detector as the last line rather than the plan.
Compare them
The finder below is already scoped to this class — 60 of the 458 products in the corpus. Widen or narrow it from there, or open the full aquarium equipment finder to search everything at once. Every result is placed against the median for its own size band, where that band holds at least eight products with a stated figure.
60 products match
5 Pack Water Leak Alarm Detector, 120dB Loud Alert, IP66 Waterproof | Water Sensor, Sensitive Leak and Drip Alert, Easy Installation for Home, Basement Flood Prevention, Bathroom, Sink, Laundry
Weight
0.45kg
Leak Detectors · 200-500 g · 11 products
Weight is +61% against the class median of 0.28.
5 Pack Water Leak Detectors for Home, 100dB Water Sensor Alarm Black | Leakage Detection Device for Pipe/Drain/Under Sink Drip, Floor Flood in Basement/Bathroom/Kitchen/Toilet/Laundry Room
Weight
0.39kg
Leak Detectors · 200-500 g · 11 products
Weight is +39% against the class median of 0.28.
Water Leak Detector for Home, 120dB, 37.8 Inches Cable, 5 Packs | Sensor Alarm for Under Sink, Sump Pump, RV, Kitchen, Basement Water Heater, Apartment Management, Powered by 9V Battery
Weight
0.29kg
Leak Detectors · 200-500 g · 11 products
Weight is +4% against the class median of 0.28.
The Basement Watchdog 110 dB Water Alarm w/Detachable Sensor for Hard-to-Reach Areas (BWD-HWA)
Weight
0.13kg
Leak Detectors · under 200 g · 14 products
Weight is +62% against the class median of 0.08.
Zircon® Leak Alert™ Water Leak Detector, Loud 90 dB Water Alarm | Detect leaks before costly water damage near water heaters, appliances and plumbing fixtures; no setup required
Weight
0.09kg
Leak Detectors · under 200 g · 14 products
Weight is +11% against the class median of 0.08.
Resideo RWD21 Reusable Water Leak Alarm,White
Weight
0.09kg
Leak Detectors · under 200 g · 14 products
Weight is +11% against the class median of 0.08.
SwitchBot WiFi Water Leak Detector, Smart Water Sensor with 100dB Adjustable Alarm&App Alerts, IP67 Waterproof, Detector for Home with Cable, No Hub Required (Support 2.4G) (White, Pack, 1)
Weight
0.07kg
Leak Detectors · under 200 g · 14 products
Weight is -17% against the class median of 0.08.
SwitchBot WiFi Water Sensor, Smart Water Leak Detector, 100dB Adjustable Alerts & App Alerts, IP67 Waterproof, Wireless Detector for Kitchen, Bathroom, Basement, No Hub Required (Support 2.4G) (3)
Weight
0.07kg
Leak Detectors · under 200 g · 14 products
Weight is -17% against the class median of 0.08.
Flood Buzz Small Water Leak Detectors for Homes & Businesses – 6-Pack | No Setup Required – Patented Design – Use Under Sink, Toilet, Basement, RV, Water Heater, Dishwasher – Reusable Alarm
Weight
0.03kg
Leak Detectors · under 200 g · 14 products
Weight is -66% against the class median of 0.08.
Water Sensor Alarm, Smart Water Leak Detector for Home & Basements | Made in THE USA | Automatic Flood Detectors and Water Alarm, Pure Water Capable (WaterWatcher)
Weight
Not stated
This listing does not publish a figure, so it cannot be placed against the baseline.
Geevon 10 Pack Water Leak Detectors,100dB Sensor Alarms for Home | Flood Leak Detectors for Basement,Bathroom,Laundry Room,Sink,Garage,Wine Cellar,RV and Window,Water Alarms with Batteries
Weight
0.45kg
Leak Detectors · 200-500 g · 11 products
Weight is +62% against the class median of 0.28.
TECKNET Water Leak Detectors for Home, 120dB Water Sensor Alarm Leak Detector, IP66 Waterproof, Water Leak Detectors for Bathroom, Sink, Laundry, Window, Basements, Kitchens(3 Pack, Battery Included)
Weight
0.28kg
Leak Detectors · 200-500 g · 11 products
Weight is 0% against the class median of 0.28.
This class publishes almost nothing
Only one listing in this category states a power figure and effectively none state anything else comparable. These are simple devices sold on features rather than specifications, and this site prints not stated rather than inventing a comparison. What can be compared is what the device does when it detects water, how it is powered, and whether it can act rather than merely announce — and those are read from the description rather than from a specification table.
Announcing a leak against stopping one
A sensor that sounds an alarm is useful only if somebody is present to hear it. A system that closes a valve or cuts power to a pump acts whether or not anyone is home, which is the difference between a wet floor and a ruined one. For an aquarium the most valuable intervention is usually stopping an auto top-off pump, since a stuck top-off is the mechanism that empties a reservoir into a room.
Where the sensor actually goes
Water runs downhill and pools at the lowest point, which is rarely where the leak starts. A sensor on the stand beside the sump catches an overflow; one on the floor at the lowest corner catches everything eventually but later. Most installations want both, and the cheap multi-sensor systems exist for that reason. A single sensor placed where the leak is imagined rather than where water collects is the common failure.
Batteries and the silent failure
A battery-powered detector that has been sitting for two years may have a flat battery, and the failure is silent by definition — nothing happens when nothing happens. Units that report low battery are worth preferring, and any unit at all is worth testing on a schedule by touching the probe to a wet cloth. An untested detector is an assumption rather than a protection.
Wired against wireless sensors
A wired sensor is reliable and tethers you to a cable run; a wireless one places freely and depends on a radio link and a battery. In a cabinet under a tank both work. Across a house to a hub, range and the metal in between decide the outcome. Where a system will trigger a valve or cut a pump rather than only sound an alarm, the wired version is generally the one to trust, because the intervention matters more than the convenience.
Common questions
Is a plain water alarm enough?
Only if someone is home to hear it. For a tank left alone, a notifying model is the one that does the job you are buying it for.
Why is there no comparison page here?
Because the only two fields clearing our gates are weight and battery voltage, and neither tells you anything about how well a detector detects.
Should I get a shutoff instead?
A shutoff stops the leak rather than reporting it, at the cost of a device that can cut power to life support. It is a real trade-off and not one we will decide for you.
Do you recommend a specific detector?
No. Sensor placement and regular testing matter more than the choice of product.