You’ve just reviewed your water consumption data. The numbers are high. Really high. And your first instinct, understandably, is to look at your tenants. Leaky toilets. Running faucets. That one unit on the fourth floor where someone clearly hasn’t replaced a flapper valve since the building opened.

But what if it’s not them?

This is actually the most common question we field when we’re walking a property team through our water monitoring program. The client is interested. They want to solve the problem. But before bringing in outside help, they want to rule out everything they can control first. Makes complete sense.

So if your tenant fixtures are already in good shape and the numbers still don’t add up, here’s where to look next.

Start With the Boiler Makeup

Boiler makeup water is one of those things that gets ignored for months, sometimes years, before anyone notices something is off.

Here’s the basic idea. Boilers lose water through normal operation. Steam escapes. Small amounts bleed off during pressure relief. The system makes up for that loss automatically by pulling in fresh water. That’s expected. What’s not expected is when that makeup rate climbs significantly without explanation.

A failed float valve, a stuck fill line, a broken heat exchanger. Any of these can cause a boiler to continuously pull in fresh water to compensate for a loss it can’t actually fix. And because the makeup process happens inside a mechanical room with no visible dripping or puddles, it can keep going indefinitely.

If your consumption numbers are elevated and you haven’t checked your boiler makeup rate recently, start there. Compare your current makeup volume against your historical baseline. If it’s drifted upward, dig in.

Check Your Irrigation System (Seasonally)

This one is time-sensitive. Irrigation leaks are very much a seasonal problem in Canada, which means they’re easy to miss if you’re not looking at the right time of year.

A cracked line, a failed zone valve, a head that’s been knocked out of position. Any of it can dump a surprising amount of water into landscaping or, worse, into the ground below it. The tricky part is that irrigation systems often run at hours when no one is around to notice. Early morning. In the middle of the night.

If you have outdoor irrigation and your high consumption is occurring during the warmer months, run a manual check of each zone. Walk the property while the system is active. Look for wet patches where there shouldn’t be any, zones that don’t seem to be reaching their targets, or heads that are clearly damaged or misaligned.

It sounds basic. But it’s also the kind of thing that gets overlooked because “someone else handles that.”

PRV and Valve Failures

Pressure reducing valves do exactly what they sound like. They take the incoming water pressure from the municipal supply, which can be quite high, and bring it down to a safe range for your building systems and fixtures.

When a PRV fails, a few things can happen. Pressure can spike, which stresses your fixtures and increases consumption. But a failed PRV can also get stuck in a partially open or fully open position, causing water to flow more freely than intended through downstream systems.

Valve failures in general are worth checking. This includes zone isolation valves, balancing valves, and any valve that’s part of your domestic or heating water distribution. A valve that should be closed but isn’t is sometimes the entire explanation for elevated consumption.

These aren’t always easy to spot visually. If you suspect a valve issue, you may need to work through your system diagram methodically and test pressures at different points in the building.

Underground Line Loss

This one is less common in Canada, mostly because our freeze-thaw cycles and construction standards create different conditions than, say, older American cities with aging infrastructure. But it can happen.

Underground line loss means water is escaping from a buried supply or distribution line before it ever reaches your building’s interior systems. Because it’s underground, there’s often no visible sign. No puddle. No wet wall. Just numbers that don’t reconcile.

Indicators to watch for include soft or unusually green patches of ground in areas near your service entry, unexplained pressure drops at the meter, or a discrepancy between what your meter registers and what your internal sub-meters are recording. If those numbers don’t match and you’ve ruled out everything else, underground loss is worth putting on the list.

Cooling Towers (If Your Building Has Them)

Not every property has cooling towers. But if yours does, they deserve attention.

Cooling towers lose water in a few ways. Evaporation is expected and normal. Blowdown, where water is intentionally discharged to prevent mineral buildup, is also normal. What’s not normal is excessive drift, where water droplets are carried out of the tower by airflow, or a blowdown controller that’s firing far more frequently than it should.

Drift eliminators can wear out. Blowdown controls can malfunction. And because cooling towers often run at high volumes during peak season, even a relatively small inefficiency can translate into significant water loss over a billing period.

If your building has a cooling tower, pull the blowdown logs and compare the cycles-of-concentration to your expected range. If something looks off, have a mechanical technician take a look before assuming it’s a fixture problem.

The Point of This Exercise

Working through this list isn’t about being exhaustive for its own sake. It’s about ruling things out systematically so that when you do bring in a monitoring solution or a conservation program, you’re solving the real problem instead of layering a solution on top of something that hasn’t been diagnosed yet.

High consumption has a cause. It’s always findable. Sometimes it’s tenant fixtures. But sometimes it’s a boiler that’s been quietly filling itself for eight months. Sometimes it’s a PRV that failed over the winter. Sometimes it’s a cracked irrigation line that only runs at 4 a.m.

Start with what you can check yourself. Document what you find. And if you’re still stuck, that’s when the data starts to do the heavy lifting.