Sewer Charges

*this does not apply to consumers on well water

If you have an irrigation system please remember to avoid turning on the system before mid-April and winterize the system by mid-October. This applies for any seasonal increased water use such as pool filling or gardening. Sewer fees are calculated based the lower of your annual water use, and your doubled winter water usage. The purpose of the “winter only” formula is to eliminate irrigation water use and other outdoor water use that do not discharge to the sewer system. Limiting your outdoor water usage to these timeframes may lower your sewer bill. If you would like to learn more about how your bill is calculated, please continue reading Understanding Your Sewer Bill.


*this does not apply to consumers on well water, see Residences on Sewer and Private Well below*

Sewer fees are based on your last year’s water use. For instance, your 2019 sewer bill is calculated using your 2018 water meter readings obtained from New Jersey American Water Company. An example follows using rates from the Montgomery Township Sewer and Water Code:

  • $266.00 base fee per unit (2019), plus
  • $14.05 per 1,000 gallons ($10.51 per CCF [centum cubic feet]) of water used, calculated from the lesser of:
    • Annual Formula: sum of usage in all 12 calendar months, or
    • Winter Formula: sum of usage in Jan + Feb + Mar + Apr + Nov + Dec, multiplied by 2

(base fee and rates are subject to change from time to time by Ordinance, 2019 fee and rates shown. Click here for RECENT HISTORY OF SEWER RATES)

Say this was your last year water bill usage:

Sample 2018 Water Utility Bill Usage (in 1,000 gallons)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
4 5 5 4 13 11 11 12 18 6 7 4

(red denotes months used in Winter Formula)

Using the Annual Formula, we calculate:

4 + 5 + 5 + 4 + 13 + 11 + 11 + 12 + 18 + 6 + 7 + 4 = 100 (100,000 gallons)

Using the Winter Formula, we get:

2 x (4 + 5 + 5 + 4 + 7 + 4) = 58 (58,000 gallons)

The annual water usage is 100,000 gallons, whereas the winter usage yields only 58,000 gallons. Montgomery takes the lesser of the two usages to determine the bill:

If we used the Annual Formula in this case, the bill would have been $1,671.00 vs. $1,080.90 using the Winter Formula. That is $590.10 in savings. You can calculate your 2019 fee by downloading this simple Excel calculator  :


(download only)

Note: There are two independent columns on the calculator you may use – the first column allows calculation based on a measure of 100 cubic feet (ccf) of water used per billing period. See your NJ American water bill. 1 ccf per year = 100 cubic feet of water per year = 2.05 gallons per day. Convert to ccf from gallons by multiplying by 0.001337. If your NJAW water bill has your water usage in thousand gallons (1000 g), then you can use the second column. If your property has a private water source (i.e. well water) and you do not intend to install a water meter, then put 90 ccf into the first month in the first column and leave the other months blank.)

Winter Use

The winter only formula uses water use from your January, February, March, April, November and December New Jersey American Water Company water bill. It is important to note that, for example, the November bill includes October water use. This is why it is important to winterize the system by mid-October. This is from a sample November bill (actual dates may vary):

Water Reducing Tips

The “Winter Months” method will not always yield the lowest bill; however for many households, water usage tends to be higher from May to October when irrigation systems are operational and pools are being filled. With this in mind, here are some tips to reduce water usage and your sewer bill:

  • Refrain from turning on irrigation systems before mid-April and winterize the system by mid-October (remember that the “Winter Months” calculation does not factor in use from May through October).
  • Inspect your sinks, toilets, refrigerators, dishwashers, washing machines, hot water tanks, irrigation systems, hose spigots, and other plumbing or fixtures for leaks. Useful link: American Water Leak Detection Kit
  • Check your water meter once water use stops and again one hour after for reading changes. If you notice an increase, you may have leaks.
  • Run dishwashers and washing machines with full loads. If available, use water saving cycle.
  • Consider upgrading appliances with water conserving or EPA WaterSense compliant appliances.
  • Consider using low flow faucet aerators, water saving showerheads, and water efficient toilets.
  • Don’t waste water, shut off faucets and garden hoses when not in use.


*Residences on Sewer and Private Well

Sewer users who also have private wells may have their sewer fee based upon water usage by having a meter installed and self-reporting the usage to the township according to the following rules:

Private Well Meter Installation Rules (as per Township Code section 12-10.4)

Please use the following fillable form on this website, if you have a well and are reporting your usage for sewer fee calculation.

Well Meter Reading Form

Important Reminders

For duplicate copies of your sewer bill, contact the Tax Collector.

Payment may be made by mail, in person, or by using our convenient on-line Sewer Bill Payment Service (2.99% Credit Card fee, 0% fee for E-checks, Debit cards not accepted).

Drop Box
For your convenience an after-hours drop box for tax & sewer payments only has been installed at the main entrance of the Municipal Building, 2261 Rt. 206, Belle Mead. Payments left in the drop box will be posted as of the next business day.

Do you have questions about your bill calculation that is explained here? Please contact the Finance Department at (908) 359-8211 ext. 223.