Think of your building's water bill as a restaurant receipt that only shows the total. You know what you paid. You don't know who ordered what.

Water submetering itemizes the receipt. A submeter measures water use downstream of the city's master meter, so an owner can see — and bill for — how much each unit uses. Some submeters go one step further and itemize by fixture, showing not just which apartment used the water, but whether it went to a shower, a faucet or a toilet that won't stop running.

That second level is where most of the value is. Here's why.

How it works

The city measures everything your building uses through one master meter, and bills you for the total. Submeters, which the owner installs, measure a share of that total. Their readings travel over a network to software, which turns them into two things: unit totals for billing, and alerts when something looks wrong.

Two kinds of submeter

Unit-level submeters sit on the pipe that feeds a single apartment. They tell you how much that unit used. They're the traditional approach, and they work well in buildings plumbed with one line per unit.

Fixture-level meters sit on the supply line of each fixture. Add up a unit's fixtures and you have the unit total — but you also know where inside the unit the water went.

On paper, both give you a number to bill. In practice, two things separate them.

Difference one: many buildings have nowhere to put a unit meter

In a lot of apartment buildings, especially older ones, water rises through shared vertical risers. One riser might feed the kitchen of 2A, the bathroom of 3A and the kitchen of 4A. There is no pipe that carries only "3A's water," so there's nowhere to install a unit meter without opening walls and re-plumbing.

That single fact explains why so many buildings still run on one master meter — and why so many owners split the bill by formula instead, using RUBS.

Fixture-level meters don't need a per-unit pipe. They go on the fixture itself, so they work with vertical or stacked plumbing in almost any building.

Difference two: a unit total can't tell you what's wrong

A unit meter can tell you 3A used twice as much water as 3B last month. It can't tell you why. Is it a running toilet? A resident who takes long showers? A kitchen faucet that never fully closes?

Those need three different responses — a repair, a conversation, a replacement — and fixture-level data tells you which one you're dealing with. The flow history behind it also helps your team decide between repairing and replacing, and gives you a clear answer when a resident asks about their bill.

What submetering gets you back

There are two separate recoveries here, and it's worth keeping them apart.

Billing on actual use lets you pass most of the city bill — around 90% — back to residents, through your billing provider or your own team. Only common-area water stays with the building.

Finding and fixing waste lowers the bill itself. Owners typically see a 20–40% or greater drop in consumption when residents pay for their own use and leaks get fixed.

There's a third effect too: residents who pay for what they use have a real reason to use less, and fixing leaks shrinks their bills further.

How DrizzleX does fixture-level submetering

DrizzleX is fixture-level water intelligence. The software does the work: portfolio totals for leadership, building views for managers, and alerts ranked by cost so maintenance handles the most expensive waste first. Flow is measured in gallons on a minute-based cadence, and urgent leaks go out by email or SMS. For resident privacy, the dashboard shows data at unit level.

Data travels over LoRa — the same radio technology utilities use for their own smart meters. Unlike cellular or Wi-Fi, it's free to use and very low energy.

The hardware is a small micrometer. One device, any fixture: it fits supply lines from 3/8" to 2" with no adapters, including a ballcock version for toilets, and installs in any position. A full apartment takes about 15 minutes, with no plumber, permits or calibration. Each device carries a 10-year device warranty and battery guarantee.

Is your building a good fit?

Fixture-level submetering tends to make the most sense if your building has one master meter and no separate pipe to each unit; if you're paying the full water bill today or recovering it by formula; if your bills keep rising while occupancy stays flat; or if you're in a market where formula billing is restricted or heading that way. Weighing the options? Read RUBS vs. submetering.

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