Calculating Your Bill

Water Meter Readings

When a Caledonia resident is served by both public water and public sanitary sewer, the sanitary sewer usage is charged based upon the water meter readings (or usage). This is the best way to estimate the amount of wastewater discharged to the sewer main during the winter. However, much of the water that customers use in the summer is directed to their lawn as irrigation. Most residential customers do not have a separate irrigation meter, and the Township doesn't want to apply sewer charges for water used for irrigation because it doesn't go down the drain.

Seasonal Use Credit

The Township's billing solution is called the Seasonal Use Credit. We take a residential customer's 1st quarter (roughly January through March, for April billing) metered water usage and apply it as the 2nd, 3rd, and 4th quarter sewer use charge if the 1st quarter is the lesser amount. The Township assumes that the additional water use was used for irrigation.

It is also important to know that the Sewer readiness to serve includes 12,000 gallons of use. If a resident's 1st quarter usage is 12,000 gallons or below, their sewer usage will be $0 for that quarter and the following 3 quarters. If the 1st quarter usage exceeds 12,000 gallons, that will be the most that they will bill for the remaining three quarters, and the resident pays for the difference in usage between the 12,000 and their actual usage.


While the Seasonal Use Credit is intended to be fair for the metered sewer and water customers, it oftentimes can create confusion and surprising bills. For example, if a customer has a leaking toilet starting in the 3rd quarter, their water and sewer bill will be marginally higher than usual because it is subject to only the water use charge of $2.28 per 1,000 gallons. Sewer use is charged based on the 1st quarter before the toilet began leaking. If the leak continues through the 1st quarter, their April utility bill will reflect the $7.28 per 1,000 gallons sewer usage charge. Sewer use has a much greater impact on the sewer and water bill.

Moral of the story: Please keep an eye out for leaks, pay particular attention to your usage in the first three months of the new year to maximize your Seasonal Usage Credit, and review the usage portion of your water and sewer bill, not just the amount. That is the best way to avoid surprises in the future!

Sample Bills

Sample Bills: How the Bill is Calculated (PDF)