Sewer charges on water that never reaches the sewer

Zak Zaloom · Commonwealth Utility Audit · 6 October 2026

Most water bills charge you twice for the same gallon: once for the water, and once for sewer. Sewer is usually the larger of the two. That makes sense for a sink or a shower, where the water goes down the drain. It does not make sense for water that evaporates or soaks into the ground.

Which water never reaches the sewer

On apartment, student housing and commercial properties, the usual culprits are a cooling tower on a larger building, a pool topped up all summer, and irrigation for the landscaping. All of it passes through the water meter, so all of it is billed for sewer, unless it is metered separately.

How to spot it on your own bills

Compare your winter water use with your summer use, per day rather than per bill, since billing periods vary in length. In winter there is little irrigation, no pool and little cooling, so winter use is close to what really goes down the drain. A large summer jump is the warning sign.

Not every summer jump is evaporation. A leak, a running fill valve or a meter fault looks similar on the bill, which is why it is worth reading the meter with everything shut off before deciding.

What a deduct meter does

Many water utilities allow a separate meter on uses that do not discharge to the sewer. Water through that meter is billed for water but not for sewer. Few buildings have one, because nobody connects the summer bills to the sewer line item.

Is it a refund?

Usually not. It is a permanent reduction that starts the month the meter goes in. In a back-audit we flag it separately from refunds for exactly that reason: it saves money every year from then on rather than recovering money already paid.