Top 5 most water leak-prone locations
Year after year, water damage remains one of the leading causes of home insurance claims* in Canada. Prevention using detectors is therefore not a luxury—it’s a necessity. But where should they be installed to maximize protection?
This choice becomes even more strategic when opting for a basic system that includes five detectors, the minimum number required by most Canadian insurers** to qualify for premium discounts. Note that detector monitoring must be in place to be eligible for maximum discounts, and some insurers may require that both the product and its installation be PREVCAN-accredited.
This article is intended as a guide. We have compiled data collected byNOWA leak detection systems between 2023 and 2025. What could be more relevant than real-world figures from condos, single-family homes, cottages, and commercial buildings? Based on these results, here is our top 5 of the most leak-prone locations (followed by an honorable mention that may surprise you):
- Kitchen and bathroom sinks
- Toilets
- Washing machines
- Water heaters
- Dishwashers
1. Kitchen and bathroom sinks
The leading causes of water damage are kitchen sinks and bathroom sinks, with 8,866 and 3,489 incidents respectively.
Together, they account for 12,355 detected leaks between 2023 and 2025 that triggered the main water valve to shut off. In line with recommendations from certified installers, sinks are the locations where detectors are most frequently installed.
While not all these leaks would necessarily have escalated into major water damage, the potential impact remains significant. For instance, if just 5% of these 12,355 events had turned into major claims, that would represent approximately 618 incidents avoided.
Using an average cost of $18,000 per claim (according to industry data in Quebec), this would amount to more than $11.1 million in potential damages avoided. These figures show that detecting a leak early near a sink is not a minor event; it is often the difference between a quick intervention and a costly claim.
Why so many leaks?
It’s no coincidence that kitchen and bathroom sinks top the list. They are among the most common water points in buildings, whether in houses, condos, or commercial properties. They are also used multiple times a day. Their high number and frequent use make them higher-risk areas for leaks.
Leaks under kitchen sinks are typically caused by worn seals, loose connections, or the buildup of grease and food residue in pipes.
Bathroom sink leaks are often due to worn seals, pipe corrosion, or faulty faucets.
Why and how to prevent damage?
Leaks can seep behind cabinets or under flooring and lead to a range of consequences:
- Wood rot
- Swelling of particleboard or melamine
- Mold growth and related health issues
- Increased water bills
- Insurance claims
- Potential financial strain
- Disruption caused by repairs
Proper maintenance is essential. However, the most reliable solution remains installing a water leak detection system. Ideally, place a detector directly under the drain pipe. For this type of location, the NOWA 2.0 detector is the most reliable option.
2. Toilets
Coming in second among the main causes of water leaks are toilets. As with sinks, this ranking is partly explained by their frequent use and the fact that they are among the most monitored locations by our detection systems. Between 2023 and 2025, toilets were linked to no fewer than 7,881 incidents that triggered the shutoff of the water supply valve.
Why so many leaks?
Toilets can leak for several reasons: worn flappers, faulty fill valves, weakened wax seals, damaged tank-to-bowl gaskets, or connections that deteriorate over time. Since these issues often begin as small leaks, they are not always immediately detected. This is precisely what makes toilets a critical point to monitor in any water damage prevention strategy.
Why and how to prevent damage?
Leaks from toilets can lead to:
- Significant water damage
- Sewer backups
- Excessive water consumption
- High utility bills
- Damage to flooring and ceilings
- Mold growth and potential health issues
- Or even flooding
Preventive measures and repairs are essential, such as replacing faulty seals. However, your best protection is the installation of a leak protection system. Place a 2.0 water detector directly behind the toilet, near the water supply and drain connections. If your bathroom floor has a slight slope, make sure the detector is positioned in the path water would take in the event of a leak.
3. Washing machines
Between 2023 and 2025, NOWA systems detected 3,675 leaks linked to washing machines.
Why so many leaks?
Washing machine leaks are typically caused by worn inlet hoses, faulty door seals, or clogged filters or pumps. An unstable installation or excessive detergent use can also lead to overflows.
Rubber hoses can burst over time or be improperly connected
- A cracked door seal may allow water to escape from the front.
- A clogged drain filter can cause leaks beneath the appliance.
- Detergent residue buildup can block drainage and cause the dispenser drawer to overflow.
- An overloaded machine may leak during the spin cycle.
- In short, there are many potential causes of damage.
Why and how to prevent damage?
Leaks from washing machines should be taken seriously due to their potential consequences:
- Major damage leading to flooding
- Deterioration of floor coverings
- Structural damage
- Mold growth harmful to health
- Electrical risks such as short circuits and shocks
In addition to standard maintenance and cleaning recommendations, the most reliable solution remains installing a leak detection system. For standard machines, place a 2.0 water detector between the wall supply and the machine connection.
Do you have a front-loading washer? Install a 2.0 detector with a base and cable to cover both the water inlet and outlet, and run the cable under the machine near its loading door.
4. Water heaters
In fourth place are water heaters, with 1,547 incidents detected by our systems between 2023 and 2025.
Why so many leaks?
Unless you have an indirect water heater, water heaters contain a large volume of water, which increases the risk if a leak is not detected in time.
A faulty pressure relief valve is the most common cause of leaks, allowing water to flow continuously during or outside heating cycles. Leaks may also result from worn seals, tank corrosion, or excessive pressure. A leak from the bottom often indicates a perforated tank, requiring full replacement.
Why and how to prevent damage?
Water heater leaks pose major risks:
- Significant water damage
- Excessive energy consumption (up to hundreds of litres wasted)
- Flooding that damages structures
- Electrical failures
- Slow drips that can turn into major leaks
Preventive and corrective actions are crucial: regular maintenance (descaling, etc.), installing a pressure reducer if needed, replacing the pressure relief valve when necessary. However, given the risks, the best way to prevent damage is to install specialized systems like those from NOWA. Use a 2.0 detector with a base and cable or a perimeter cable around the water heater. Make sure to place a drain pan underneath it. Additionally, insurers generally recommend replacing the water heater every ten years to ensure optimal safety and coverage.
5. Dishwashers
Dishwashers rank fifth among the locations most at risk of water damage according to our data, with 1,311 incidents detected between 2023 and 2025. These figures do not include incidents related to nearby sinks.
Why so many leaks?
Dishwasher leaks are often caused by faulty door seals, improper leveling, excessive detergent use, or plumbing issues.
Cracked or worn hoses are a common cause. Internal components such as a worn drain pump or a clogged water distributor can also be responsible.
Why and how to prevent damage?
Leaks from dishwashers should not be underestimated:
- Damaged flooring
- Deteriorated cabinetry
- Costly repairs
- Potential short circuits
- etc.
A dishwasher safety float (anti-overflow device) can detect leaks, but accumulated water still poses a risk. The best prevention remains installing reliable detectors like those from NOWA. Place a wired detector behind the dishwasher and run the cable along the inlet and drain hose up to under the sink.
Honorable mention: refrigerators with water dispensers or ice makers
While not part of the top five, we recorded 1,343 incidents involving such refrigerators between 2023 and 2025. Although this number may seem low, considering the few detectors installed in this area, it accounts for a significant share of leaks.
The water line behind this type of refrigerator is not designed to last for many years. It should be regularly maintained or replaced with a higher-quality line if you want to avoid worrying about it. If your refrigerator with an ice maker or water connection was installed more than five years ago, prevent damage by installing a NOWA water detector.
Prevention: the ultimate solution in every situation
In 2025 alone, NOWA prevented more than 18,000 water damage incidents. By targeting strategic locations and installing the right detectors, you can prevent major damage and protect both your property and your peace of mind.
Now that you’re aware of the top 5 leak-prone areas, learn more about where to place our different types of detectors. Also, work with installation experts to ensure complete protection—find a certified installer.
Ready to get protected today? Get a 4Se starter kit, including five water and freeze detectors.
*Source: Insurance Bureau of Canada
**Sources: Desjardins, La Personnelle, Intact Insurance
