Save Money on Your Water Bill with a Deduct Meter
A deduct meter (sometimes called a sub-meter or irrigation meter) is a second water meter installed on the line that feeds outdoor faucets, irrigation systems, or pool fills. It measures water that goes onto your lawn, garden, or driveway rather than down the drain. Your water utility deducts that volume from the sewer charge portion of your bill, so you only pay the sewer fee for water that actually entered the sewer system.
For southern New Hampshire homeowners with sizable lawns, irrigation systems, or summer pool fills, a deduct meter often pays for itself in one to two years. At A.J. LeBlanc Heating, our licensed plumbers install deduct meters across NH.
How the sewer charge works in NH
Most NH municipalities that provide both water and sewer service put two separate fees on the water bill:
- Water charge: based on the total volume of water delivered to the home (measured at the main meter)
- Sewer charge: based on the same volume, on the assumption that everything that came in eventually goes down the drain
The sewer charge is typically 1.5 to 3 times the water charge per gallon because sewer treatment costs more than supply. For water that never enters the sewer (irrigation, pool fill, vehicle washing on the lawn), you are paying a sewer fee for a service that was not provided.
What a deduct meter does
The deduct meter is plumbed on the branch line that feeds outdoor uses. It accumulates a separate gallon count that the utility deducts from the sewer charge calculation. The water portion of the bill stays the same; only the sewer portion goes down.
Typical savings depend on outdoor water use:
- A 10,000 sq ft lawn with weekly irrigation can use 20,000 to 50,000 gallons per summer
- A pool fill is typically 15,000 to 30,000 gallons
- Frequent vehicle washing, garden watering, and outdoor cleaning add up
At typical NH sewer rates, deducting these volumes from the sewer charge can save $100 to $500+ per year for households with significant outdoor water use.
Who benefits most
- Homes with in-ground irrigation systems
- Homes with large lawns that are watered regularly
- Homes with swimming pools that need topping off or seasonal fills
- Hobby gardeners with extensive outdoor watering
- Households on municipal sewer (deduct meters typically do not apply to homes on septic since there is no municipal sewer charge to deduct from)
How a deduct meter is installed
Installation involves:
- Identifying the line that feeds outdoor faucets and irrigation
- Installing a tee, shut-off valves, and the deduct meter in line with that branch
- Configuring the meter according to your utility's specifications (model, register type, remote reading capability if required)
- Coordinating with the utility for inspection and registration of the meter
The deduct meter must be a model approved by your specific water utility. Different NH utilities have slightly different rules about which meters are accepted, how they are registered, and how readings are submitted. Our plumbers handle the utility coordination as part of the install.
Common requirements (vary by NH utility)
- The deduct meter must be installed by a licensed plumber
- The meter model and register type must be approved by the utility
- Some utilities require the meter to be read by their staff; others accept homeowner-submitted readings
- Initial registration paperwork is filed with the utility
- Some utilities charge a small annual administrative fee for deduct meter accounts
Cost vs. payback
Installation cost depends on the plumbing configuration but is typically in the $400 to $900 range for a straightforward residential install. For a home with heavy outdoor water use, the payback is often less than two summers. After that, the savings continue every year for the life of the home.
Schedule a deduct meter consultation
If your NH home has an irrigation system, large lawn, or pool, and you are paying meaningful sewer charges every summer for water that never enters the sewer, a deduct meter is worth a look. Contact A.J. LeBlanc Heating. Serving New Hampshire families since 1928.
Frequently Asked Questions
How much can a deduct meter save?
For homes with significant outdoor water use (irrigation, pool fills, lawn watering), typically $100 to $500+ per year on the sewer portion of the water bill. Higher for properties with very large irrigated areas.
Will a deduct meter work in my town?
Most NH municipalities with municipal water and sewer service allow deduct meters, but specific rules and approved meter models vary by utility. We confirm eligibility with your specific water utility before installation.
Do I still get charged for the water through the deduct meter?
Yes. The water charge stays the same. Only the sewer charge is deducted for the water that goes outside.
How long does deduct meter installation take?
Typically 2 to 4 hours of plumbing labor, plus utility inspection scheduling. Most installations are completed in one visit.
Can I install a deduct meter myself?
In most NH municipalities, no. Deduct meter installations require a licensed plumber and utility inspection. DIY installations are usually not registered with the utility and therefore do not produce the bill deduction.