Lee Hoffman
Water waste rarely announces itself. There's no alarm, no emergency call, no visible damage. Just a toilet running quietly in a unit somewhere in your building, adding to your water bill every single day.
For property managers and building owners overseeing multifamily residential buildings, that silence is the problem. A single running toilet can waste hundreds of gallons a day. Multiply that across a portfolio of buildings with dozens or hundreds of units, and the financial exposure adds up fast, often before anyone realizes there's a problem to fix.
In New York City, building owners pay $13.07 per 100 cubic feet (CCF) of water, roughly 748 gallons.1 Water costs in NYC have risen 26.62% since 2020, meaning the math on undetected waste is considerably worse than it was just a few years ago.
A large toilet leak, meanwhile, can waste up to 6,000 gallons per day.2 At current NYC rates, that's just over $100 a day and nearly $38,000 a year from a single toilet.
Even a single toilet with a moderate leak carries significant costs over time. An open fill valve wasting three to five gallons per minute runs to approximately $22,000 annually. Even smaller, silent leaks that are hard to detect and are the least likely to get reported, but can and do happen, still cost $1,500 to $2,000 per toilet per year. New York’s Multiple Dwelling Law requires every apartment to have at least one toilet, for around 25-40 toilets per building. If each toilet has a tiny leak, this could be costing between $37,500 and $80,000 a year!
Now put that across a 100-unit building where 10% of toilets are running at any given time. The annual exposure isn't a rounding error. It's a line item that belongs in every operating budget conversation.
Utility bills don't tell you which toilet is running. They tell you weeks later that something changed, and by then the waste has already been building for months. Pinpointing the source is even harder. Water usage shifts constantly, and there's no way to tell from a bill alone whether a spike came from a leaky toilet or just a busier-than-usual month.
Even when a spike is visible, tracking it to a specific unit means physically checking every toilet in the building. In a 50- or 100-unit property, that kind of manual sweep isn't a realistic part of anyone's maintenance workflow.
Tenants aren't a reliable signal either. A running toilet in a private unit is easy to overlook, especially when the building pays the water bill. Most leaks go unreported not because tenants are negligent, but because there's genuinely no financial reason for them to notice. Water usage fluctuates for all kinds of reasons:
So even a tenant who notices something unusual may chalk it up to normal variation and move on.
Part of the issue is that toilets leak for all kinds of reasons. To make matters worse, the average person knows little about plumbing. So, unless a catastrophe occurs, toilet leaks are often ignored on the tenant side.
Some of the most likely causes of a leak include:3
The common thread: none of these failures create an obvious emergency. Water moves through the system quietly, usage climbs gradually, and the cost compounds until the bill arrives.
The reality is that toilets leak. Parts break down over time, and there’s nothing you can do about that.
However, you can address the issue of leaky toilets with some proactive approaches.
Smart toilet monitoring solves the core problem: you can't physically check every toilet in your building on a regular basis, but a sensor can keep watch around the clock. Modern running toilet detection systems help property teams identify leaks much sooner than traditional inspections or utility bill reviews.
The technology is straightforward. Our wireless sensors clip onto the toilet's water supply hose and detect the temperature differential created by continuous water flow. A running toilet keeps the hose cooler than the surrounding air, so when the sensor catches that signal it sends an alert directly to the property team with the exact unit location, meaning by the time the next water bill arrives, the leak has already been found and fixed.
Installation takes roughly 10 seconds per toilet with no plumbing work, no water shutoff, and no tenant coordination required, so most buildings are fully set up in a single visit. From there, the system runs continuously in the background, and catching one or two leaks typically covers the cost of the entire installation.
Replace Old Toilets
For buildings with toilets manufactured before 1994, a full replacement is worth putting on the capital planning radar. Modern high-efficiency toilets (HETs) use significantly less water per flush, and older units are simply more prone to the kinds of mechanical failures that cause running toilets in the first place, so the long-term savings can justify the upfront investment.
That said, replacing every toilet in a building before it fails is a major undertaking. The cost alone makes it a rare proactive move for most building owners, and the tenant disruption that comes with a full retrofit, including noise and temporary water shutoffs, adds another layer of complexity to the decision.
Scheduling regular plumbing checks is a reasonable way to catch running toilets between billing cycles. A plumber doing periodic rounds of the building can identify mechanical issues before they compound into a larger water bill, and it puts the detection process in professional hands rather than relying on tenants to report problems.
The tradeoff is cost and logistics. Routine plumbing visits add up quickly, and getting unit access means coordinating with tenants on a recurring basis, which gets complicated fast in larger buildings.
Sharing guidance with tenants on what a running toilet looks and sounds like is a low-cost step that's worth taking. A notice in the elevator or a building-wide email can go a long way toward surfacing issues that might otherwise go unreported for months. Signs tenants should know to flag include:
The honest limitation is that this approach depends entirely on tenants paying attention and following through, and in buildings where the tenant pays nothing toward the water bill, that's a hard thing to count on. It works best as one layer of a broader strategy rather than a standalone solution.
The financial case is straightforward, but the reasons to act go beyond the water bill. Running toilets that go undetected long enough tend to create problems that compound well beyond the original fault:
A toilet that costs your building $20,000 a year doesn't announce itself. It just runs, quietly and continuously, until someone happens to find it or the water bill arrives with an unwelcome surprise.
Runwise Smart Toilet Monitoring gives property teams an earlier signal. Sensors install across an entire building in a single visit, run continuously in the background, and send an alert directly to your phone or dashboard the moment a toilet starts running. Most buildings find their first leak within 24 hours of going live, and in most cases that one find covers the cost of the entire system.
Get an estimate (in under 90 seconds) of how much our smart heating controls could save your building.
