# What Is Water Submetering? How It Works, Costs and Savings

Source: https://submeter.com/what-is-water-submetering/
Publisher: National Exemption Service (NES), https://submeter.com. Last reviewed September 2026.

Water submetering bills each unit for the water it uses. See how the system works, what install costs, and how submetered units used 34% less water.

## What is water submetering?
Water submetering puts a private meter on each unit's water line, behind the city's master meter. The city keeps billing the property for the whole site. The submeters record what each apartment, condo or home used, and each resident is billed for that share. A wireless transmitter sends the readings several times a day, and billing software turns them into monthly statements. Common-area water stays with the owner, and residents are never billed more than the master bill. Once residents pay for their own water, use typically drops 15 to 30 percent.

If you manage or own an apartment community, a [condominium association](https://submeter.com/submetering-in-a-condo/) or a [mobile home park](https://submeter.com/submetering-for-mobile-home-parks/), you know how fast city water rates climb. This guide explains how the system works, what equipment and labor cost, and what to ask before you sign with anyone. You will see clearly whether submetering fits your property.
## What a water submetering system is
Most older multifamily properties rely on a single city water meter. The municipality tracks total property consumption, bills you directly, and leaves you stuck with the bill. You have no way to know which resident wastes water and who conserves it. In a master-metered building, rising water rates eventually push rent up because the owner has nowhere else to put the cost.
Submetering introduces private meters downstream from the main utility connection. A meter goes directly on the incoming cold supply, or on both the [hot and cold lines](https://submeter.com/submetering-hot-water/) if your pipe layout requires it. That setup tracks only the water consumed inside that specific apartment or home.
These setups never replace the city meter. The local utility bills you for total site use just like before. Submeters simply provide the numbers to allocate costs based on true individual use. Common-area water (laundry, irrigation, pool) is measured separately and stays with the owner, and the total billed to residents never exceeds the property's actual master-meter water cost.

## The parts of a water submetering system
A working setup relies on several connected pieces of [submetering equipment](https://submeter.com/submetering-meters/), and a failure at any stage disrupts your billing.
1. Meter: Measures the water one unit uses
2. Transmitter: Broadcasts meter readings over radio frequencies
3. Repeater: Relays radio signals across the property
4. Gateway: Collects readings and transmits via cellular
5. Billing software: Checks readings and calculates charges
6. Resident bill: Itemizes water usage and amount due
Data flows from the meter and transmitter through repeaters to the gateway, feeding billing software that produces the resident bill.
### The meter
The meter sits right on the supply pipe serving the unit. Water moves through an internal chamber built around a nutating disc or an oscillating piston, turning the register as liquid flows. Proper [meter accuracy](https://submeter.com/are-submeters-accurate/) depends on hardware built to recognized accuracy standards, sized correctly for the unit and installed properly.
![Row of three water meters with dials and register numbers installed on supply pipes.](https://submeter.com/wp-content/uploads/2019/05/CostofInstallingSubmeters.jpg)
Three residential water meters with readable dials are mounted in a row on supply pipes.
### The transmitter
A compact battery-powered radio transmitter connects to the meter's register. As the meter logs each increment of water, the transmitter updates its internal count and broadcasts the data wirelessly. Thanks to long-life batteries, nobody needs to run electrical wiring into individual units.
### Repeaters and gateways
Transmitters across spread-out properties cannot always reach the main receiver unassisted. Repeaters placed on outside walls, inside breezeways or throughout common areas capture those faint signals and relay them forward. They route the data to a cellular gateway, which gathers consumption numbers from every home and forwards them to the billing platform.
### The billing software
When reads hit the billing platform, the software handles the calculations. It applies your property's rate structure, compares consumption against past trends, and flags anomalies like sudden spikes or frozen meters. From there, it produces each resident's bill and your usage reports.

## From faucet to bill: how water submetering systems work, step by step
Here is how a single gallon travels from the tap to an itemized invoice.
1. A resident washes dishes, runs the laundry or flushes a toilet, drawing water directly through the unit's meter.
2. The meter measures that volume and transmits a signal to its connected radio unit.
3. The transmitter sends out an updated consumption reading over the air, several times a day.
4. Where your property needs them, repeaters relay the radio signal to the on-site gateway.
5. The gateway packages every incoming read and pushes the batch to the billing platform via cellular network.
6. The billing platform scans the data for issues like stopped meters and applies your rates.
7. Residents get an itemized statement detailing their consumption and charges, sent by mail or posted to an online portal.

## How meters are read
Your method for reading meters matters just as much as the hardware. Traditional methods still count on a person walking the property.
| Reading method | How it works | How often you get data | What it means for leak detection |
| --- | --- | --- | --- |
| Manual reading | A technician walks the property and records each meter's number by hand or on a handheld device. | Monthly, at best | Low. A leak can run all month before anyone sees the higher number. |
| Drive-by (AMR) | A technician drives through the property with a mobile receiver that picks up each transmitter's signal. | Monthly, once per billing cycle | Low to moderate. Reading is faster, but you still only get data when someone drives by. |
| Fixed-network (AMI) | Permanent repeaters and a gateway collect the signals automatically, with no one on site. | Several times a day | High. A leak or a dead meter shows up within a day. |
If you only read meters once a month, a running toilet turns into an ugly surprise after gallons have already poured down the drain. Modern systems transmit several times a day, giving you [apartment leak detection](https://submeter.com/apartment-water-leak-detection/) that spots failed equipment or hidden leaks within a day. That lets you dispatch maintenance instead of explaining a massive bill.
NES provides daily leak tracking through the [MyReads portal](https://submeter.com/myreads-leak-detection/). The system highlights continuous overnight flow, which is the usual sign of a running toilet or a leak, so your maintenance crew can fix it fast.

## What a water submetering system costs
Planning a budget for submetering comes down to three basic expenses:
1. Installation. Plumbing labor to splice each water line, install meters, mount wireless transmitters and configure the network.
2. Equipment. Physical equipment including meters, radio transmitters, signal repeaters and the cellular gateway.
3. Monthly billing fee. Monthly service charges covering meter reading, resident billing, account support and property reports.
Installation averages $150 to $300 per unit. The [water submeter installation cost](https://submeter.com/how-much-does-submetering-cost/) for your property can change based on the factors below:
- How many meters each unit needs.
- The meter type.
- Whether meters go indoors or outdoors.
- Whether your property is new construction or a retrofit.
- How easy each unit's water line is to reach.
- Whether NES installs or supplies equipment for your own plumber.
Pipe access drives installation cost more than anything else. An open pipe in a utility closet makes for quick work. Pulling out a water heater to reach the connection requires extra labor and pushes the cost up. That is why individual unit costs can vary on the same property.
Payback is where the numbers get interesting. Most properties earn back the install cost in 12 to 18 months from recovered water expenses, and some see it sooner. That recovery continues every year after that. Your actual result depends on your current water bills and rates, which is why NES prices from your actual bills rather than general assumptions. You can check the numbers yourself with our [online ROI calculator](https://submeter.com/roi-calculator/).
Take a real example from NES property records. At one 337-unit community, NES added meters as leases renewed, so for a while both setups ran side by side. The 168 submetered units averaged 3,868 gallons per unit per month, 34% less than the 5,846 gallons used by the 169 units not yet metered. Their average bill was $54.22 a month against $84.72, 36% lower, or about $30 per unit. Across all 337 units, that gap is worth roughly $123,000 a year. This is one property, not a promise.
See the math for your property. NES runs the numbers on your property's actual master-meter water bills and sends a free, no-obligation estimate. A specialist will review your details and reply within one business day.

## What installation looks like
Owners often delay projects out of concern over site disruption. In reality, a planned [submeter installation](https://submeter.com/how-much-does-submetering-cost/) moves quickly. Total time depends on your building count, property layout and line access. Equipment and resident billing are usually live within a few weeks to about 90 days, depending on the property, and NES provides a schedule once the site survey wraps up.
![NES technician Dave Hanson kneeling beside a wall, using pliers to connect a submeter to white pipe.](https://submeter.com/wp-content/uploads/2019/07/freewatermeter.jpg)
![Hands using pliers to fit a water submeter and transmitter onto a white PVC pipe.](https://submeter.com/wp-content/uploads/2019/07/water-meter.jpg)
Dave Hanson, an NES technician, installs a water submeter with an attached radio transmitter onto a supply pipe.
1. Site survey. A technician surveys pipe configurations, potential meter locations, plumbing access points and radio signal paths across your property.
2. Resident notice. Your office alerts residents ahead of scheduled work so everyone knows when crews are on site. Water service shuts off only briefly while plumbers cut the meter into the supply line.
3. Meter installation. When the line is easy to reach, a meter goes in in under 30 minutes, and the plumber needs a space about the size of a football to fit it. Water to the unit is off only during that work, and NES can handle the installation or supply equipment for your own plumber.
4. Network setup. Repeaters go in where the property needs them and the gateway is powered up. Your maintenance team can often mount both. Each meter is checked to confirm it transmits an accurate starting reading.
5. Test period and first bills. We monitor incoming reads until signals stabilize so no one gets billed on incomplete data. Once confirmed, residents receive their initial statements.

## Rules and resident communication
Submetering and billing rules vary by state and city, and some states require registration with agencies like the [Texas PUC](https://www.puc.texas.gov/industry/water/watersystems/submeter/) or the [North Carolina Utilities Commission](https://www.ncuc.gov/industries/water/waterresale.html). NES checks the rules for your exact address before quoting so you know what is allowed. See our guides for [submetering in Texas](https://submeter.com/submetering-in-texas/) and [submetering in North Carolina](https://submeter.com/submetering-in-north-carolina/) to review state rules in detail.
Residents accept utility billing much better when communication is clear from the start. Provide written notice well before the first cycle and have every resident sign a utility addendum explaining the terms. When residents understand the process up front, your leasing office avoids angry phone calls.

## Submetering or RUBS
Physical meters are not always practical for every property. In some buildings, the plumbing makes reaching each unit's line too hard or too costly, or the budget is tight. In those situations, [ratio utility billing](https://submeter.com/submetering-vs-rubs/) offers an alternative by dividing master bills through formulas based on unit square footage or occupant count, with virtually zero upfront setup cost.
The catch with RUBS is that it measures nothing. A resident away on business pays by the same formula as a neighbor running water all day, which weakens fairness and reduces conservation incentives. RUBS is also not allowed everywhere. NES handles both options and helps you choose what fits your layout, budget and local rules. You can weigh the options with our [RUBS vs submetering calculator](https://submeter.com/rubs-vs-submetering-calculator/).

## Questions to ask before you choose a submetering company
Any provider you interview should answer these questions directly.
- Who owns the meters?. Choose nonproprietary meters that you own, backed by a warranty, so you are never [locked in](https://submeter.com/switch-submetering-providers/) to a single billing company. With proprietary hardware, switching providers can mean replacing every meter on the property.
- How often are meters read?. Monthly manual reads keep you blind to plumbing issues until the damage is done. Ask for an automated system that transmits readings several times a day.
- Do you offer leak alerts?. Confirm the system sends daily alerts for continuous night flow so your team fixes a running toilet before the bill spikes.
- Who answers resident calls?. Your on-site staff has enough to do without fielding utility calls. NES manages the entire workflow in-house, including installation, meter reading, resident billing and bilingual customer support.
- What are all the fees?. Ask for an itemized breakdown that separates equipment costs, physical installation charges and monthly billing fees.
- What does the warranty cover?. Review the separate warranty coverages for meters and transmitters, and clarify how quickly replacement parts get supplied if hardware fails.
- How do you handle state and local rules?. Make sure the provider reviews local ordinances and utility commission registration requirements for your property address before quoting.

## Questions
**Is apartment water submetering worth it?**
For most properties, yes, though your own bills decide it. When residents pay for their own water, you recover an expense that previously came out of your operating budget. Payback on installation typically takes 12 to 18 months, with some properties recovering costs even sooner and continuing that recovery year after year. NES reviews your actual bills to show where you stand.

**How accurate are water submeters?**
Reliable performance requires hardware built to recognized accuracy standards, sized correctly for the unit and installed properly. A poorly placed or incorrectly sized meter produces erratic reads, which makes the quality of installation just as important as the meter itself.

**Who pays for the meters and installation?**
Property owners generally fund the initial equipment and installation costs, retaining full ownership of the meters. A monthly fee covers automated meter reads, statement generation, resident customer service and reporting. Whether that charge can be billed back to residents depends on state regulations and your lease terms, so get an itemized quote up front.

**How long does water submeter installation take?**
Timeline depends on your unit count, building layout and how accessible plumbing lines are. A meter goes in in under 30 minutes when the line is easy to reach, and water is shut off only briefly during that work after residents receive advance notice. NES provides a firm schedule following the site survey, and equipment and resident billing are usually live within a few weeks to about 90 days.

**What happens when a meter or transmitter fails?**
Because modern wireless meters report several times a day, a failed register or radio transmitter shows up within a day instead of remaining hidden until the next billing cycle. Your provider tests the unit to diagnose the problem and replaces the part under the meter warranty.

**Does submetering reduce water use?**
Usually, yes. Properties typically see water use drop 15 to 30 percent once residents pay for their own water, because people notice leaks and curb wasteful habits. At one 337-unit community metered as leases renewed, the 168 submetered units used 34% less water than the 169 not yet metered (3,868 vs 5,846 gallons per unit per month). Results vary from one property to the next.