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A separate water meter can be a fairly simple plumbing job or a much larger utility project. The biggest question is what kind of meter you need.
A private submeter usually measures water use inside your property. A true second utility meter creates a separate metered service that the water provider recognizes for billing. The second option can involve utility fees, permits, trenching, service-line work, a meter box, and plumbing changes.
Because water utilities set their own connection rules and fees, there is no useful one-size-fits-all installation cost. Before hiring a plumber, ask your water provider what type of separate meter it allows and which parts of the installation you must pay for.
What Does a Separate Water Meter Mean?
People use the term "separate water meter" for several different setups.
A Second Utility Meter
A second utility meter is connected to the public water system and recognized by the water provider.
It may be used for:
- A second dwelling
- An accessory dwelling unit
- A rental unit
- A separate building
- Irrigation
- Commercial and residential portions of the same property
Depending on local rules, the second meter may create its own water account and bill.
The utility often controls the meter itself. For example, Portland's current water code says most new water-service meters are supplied and installed by the Water Bureau and remain Water Bureau property. New York City also states that its water meters are owned and maintained by its Department of Environmental Protection.
A Private Submeter
A submeter is installed after the property's main utility meter.
Water still enters through the original service connection, but the submeter records how much goes to one part of the property.
For example:
Street main → utility meter → house plumbing → submeter → irrigation system
A submeter might track water going to:
- A garden
- An apartment
- A workshop
- A guest house
- A greenhouse
- A livestock area
- Another part of a building
A private submeter normally does not automatically create a separate utility account. The property still has one main meter from the water provider.
A Meter for a Rainwater System
If your goal is simply to measure how much stored rainwater you use, you usually do not need another municipal water meter.
An inline meter can sometimes be installed in the rainwater plumbing instead.
For example:
Rainwater tank → pump → filter → water meter → irrigation line
That can help you track tank use, identify unusual consumption, or compare rainwater use with municipal water use.
Keep rainwater plumbing properly separated from potable plumbing. Where the two systems interact, local plumbing and backflow-prevention requirements become especially important.
Why Does the Installation Cost Vary So Much?
The meter itself may be only one small part of the job.
A separate utility meter can require work from both the water provider and a licensed plumber.
Utility Connection Requirements
First, the utility must determine whether another meter can be added to the property.
Some utilities allow multiple meters from a shared arrangement. Others may require a separate service connection.
Portland, for example, currently allows multiple meters on some single tax lots and has specific arrangements for separate meters serving certain residential developments. These rules are local and should not be assumed to apply elsewhere.
As of August 2026, check your own water provider's current rules before planning the plumbing.
New Service Line
A second meter becomes a much larger job if it needs another service line from the public water main.
That may involve:
- Excavation
- Cutting pavement or sidewalk
- Connecting to the water main
- Installing valves
- Installing a meter box
- Running pipe to the property
- Restoring pavement or landscaping
This can make a true second utility service far more involved than adding a private submeter.
Existing Plumbing
The plumber also needs to separate the plumbing that will be measured by the new meter.
Imagine a house and guest house that currently share the same water line. Installing a meter does little good if their plumbing remains mixed together.
The plumber may need to reroute pipes so each meter serves the correct fixtures.
Meter Size
The correct meter and pipe size depends on the expected water demand.
A meter that is too small can restrict flow. An oversized meter may add unnecessary complexity and may not match utility requirements.
For a dwelling, the utility or plumber may consider the number and type of plumbing fixtures when sizing the service. Portland, for example, uses fixture information when determining residential meter size.
Distance
Long pipe runs require more material, excavation, and labor.
Installation is generally simpler when the meter can be placed near an existing service line and the plumbing it will supply.
Excavation Conditions
Digging through an open yard is different from working beneath:
- Concrete
- Asphalt
- A driveway
- A patio
- A retaining wall
- Mature landscaping
Existing electrical, gas, sewer, drainage, and communication lines can also limit where a new water service can run.
Do not excavate around buried utilities without having them properly located first.
Backflow Protection
Some separate services or irrigation systems may require backflow protection.
A backflow device helps stop water from flowing backward into the drinking-water supply.
Requirements depend on the plumbing arrangement and local rules. Portland, for example, notes that some service changes can trigger additional backflow requirements.
This is especially important where irrigation, rainwater, chemical treatment, or another non-potable water source is involved.
Review cost tradeoffs of a dedicated landscape water meter to understand garden demand against the available rainwater supply.
Potable means water intended and treated for drinking. Non-potable water is water that is not approved for drinking.
What Is Usually Included in the Job?
For a true second utility meter, your total project may contain several separate parts.
| Part of the job | When it may be needed |
|---|---|
| Utility application | Usually needed for a utility-recognized meter |
| Connection or service work | If another connection must be created |
| Meter and meter box | Required for the new metered service |
| Plumbing permit | Required in many jurisdictions |
| Excavation | Needed for buried lines or meter boxes |
| New water pipe | Connects the meter to the building or system |
| Plumbing separation | Needed when existing fixtures share one line |
| Shutoff valves | Allows the new service to be isolated |
| Backflow protection | Required for some applications |
| Testing or inspection | May be required before service is activated |
| Surface repair | Needed after disturbing pavement or landscaping |
Ask for an estimate that clearly identifies what the utility handles and what your contractor handles.
Otherwise, an inexpensive-looking plumbing quote may leave out major utility or excavation work.
Is a Private Submeter Cheaper Than a Second Utility Meter?
In most straightforward installations, a private submeter is the simpler option because it uses the property's existing water service.
There is no additional connection to the water main.
For example:
Utility main → existing utility meter → submeter A → house
Utility main → existing utility meter → submeter B → irrigation
The problem is that a private submeter may not accomplish what you actually want.
If your goal is to have a tenant receive a separate bill directly from the municipal water provider, installing your own meter does not necessarily accomplish that. Utility billing rules determine whether individual accounts are available.
If your goal is simply to measure how much water a garden, rental area, or secondary building uses, a private submeter may be enough.
Check local rules before using a private submeter to allocate charges between tenants.
Does an Irrigation Meter Make Sense?
Some properties use a separate meter specifically for outdoor irrigation.
The main reason is usually billing rather than water pressure. Some utilities calculate sewer charges partly from metered water use and treat separately metered irrigation differently because that water does not enter the sewer system.
But this varies greatly by location.
Do not assume an irrigation meter will reduce your utility bill. Find out:
- Whether your utility offers irrigation meters.
- Whether another meter changes sewer billing.
- What connection work it requires.
- Whether there are ongoing account or service charges.
- Whether backflow protection is required.
Then compare the long-term benefit with the installation work.
For a rainwater-fed irrigation system, a municipal irrigation meter normally would not measure the water coming from your rain tank unless the plumbing was specifically designed for that purpose.
Can You Install a Separate Meter Yourself?
A homeowner may be able to install certain private monitoring meters where local plumbing rules permit it.
A utility meter is different.
Do not modify, relocate, disconnect, or connect plumbing on the utility's side of the water service unless the water provider specifically permits you to do so.
Work involving a public water main, utility meter, buried service connection, backflow device, or major changes to potable plumbing should normally be handled through the utility and qualified plumbing professionals.
This also reduces the chance of creating leaks, contamination risks, or an unapproved cross-connection.
How to Get an Accurate Estimate
Start with the water utility rather than buying a meter.
Tell them exactly what you are trying to accomplish, such as:
- Separate billing for an accessory dwelling
- Separate billing for two houses
- Tracking a tenant's water use
- Measuring irrigation use
- Measuring rainwater use
- Separating commercial and residential water
- Monitoring water going to an outbuilding
Ask whether you need a second utility meter, separate water service, or private submeter.
Then find out what the utility will install and what must be completed by a plumber.
Once you know that, a plumber can inspect the property and estimate the private-side work.
This approach gives you a much more useful number than asking only what it costs to "install a water meter."
When a Separate Meter May Not Be Worth It
A second utility meter may not make sense when your only goal is to understand where water is being used.
A private meter or flow monitor may provide the information you need without creating another utility service.
For a rainwater system, you might also be able to measure:
- Water leaving the storage tank
- Irrigation consumption
- Household non-potable use
- Pumped water volume
Choose the meter based on what you need to measure, not simply because the property has two water systems.
If separate utility billing is the goal, however, start with the water provider. Only the utility can tell you what arrangements it recognizes for billing.
Frequently Asked Questions
How much does it cost to add a second water meter?
There is no reliable national figure. A private submeter can be a relatively simple plumbing addition, while a utility-recognized second meter may require service fees, excavation, permits, new piping, and utility work. Ask your water provider for its current requirements before getting a plumbing estimate.
Can I have two water meters on one property?
Sometimes. Water utilities have their own rules about multiple meters on one lot. The answer may also depend on whether you have two dwellings, separate buildings, an accessory dwelling, or an irrigation system.
Can a plumber install a second water meter?
A plumber can often install the private-side plumbing and some types of submeters. A municipal utility meter may have to be supplied, installed, approved, or activated by the water provider.
Is a submeter the same as a separate water meter?
Not exactly. A submeter measures part of the water passing through an existing main meter. A separate utility meter may have its own recognized service and billing arrangement.
Do I need a separate meter for a rainwater tank?
Usually not just to measure rainwater use. An appropriate inline meter can often measure water leaving the tank. However, connections between rainwater and potable plumbing can be subject to plumbing and backflow rules.
Can a separate meter lower my sewer bill?
Possibly, especially where a utility offers special metering for irrigation or other water that does not enter the sanitary sewer. Policies vary by utility, so check the current billing rules before installing anything.
Do I need a permit to install another water meter?
A utility-installed meter normally requires utility approval, and plumbing or excavation permits may also apply. Requirements vary by jurisdiction. Check with both your water provider and local building or plumbing authority before work begins.
