Are You Overpaying Sewer Charges? What NYC Property Owners Must Know

If you manage or own commercial property in New York City, you've probably noticed that your sewer charge often exceeds your water charge. That's not an accident — most municipalities bill sewer as a fixed multiple of water consumption, sometimes two or even three times the water rate. The underlying assumption is simple: every gallon that comes in must go out through the sewer. But that assumption is frequently wrong, and when it is, you're paying for water that never touched the drain.

This is not a niche accounting error. It's one of the most consistent and recoverable sources of overbilling in commercial utility accounts — and it's hiding in plain sight on nearly every property that uses water for irrigation, cooling towers, industrial processes, or any other non-sewered purpose.

How Sewer Billing Actually Works
Most utility districts — including New York City's DEP (Department of Environmental Protection) — calculate sewer charges as a percentage of total water consumption measured through your main meter. The logic holds for typical residential use, where nearly all water used indoors eventually drains into the sewer system. But commercial and mixed-use properties are different.
Consider a building with a rooftop cooling tower, a landscaped courtyard, or even a car wash on the ground floor. Water consumed by those systems doesn't end up in the sewer — it evaporates, soaks into soil, or is recaptured. Yet the utility charges for it as if it did. Over twelve months, that silent overcharge can compound into thousands of dollars in recoverable costs.

When Is a Separate Meter Worth Installing?
A deduct meter — sometimes called an irrigation meter or a sewer credit meter — measures the water flowing to a specific use that bypasses the sewer. That reading is then submitted to the utility as documentation supporting a reduced sewer charge. Whether it makes financial sense depends on a few factors.
First, confirm that your municipality actually offers this credit. Every utility has its own rules. Some require a physical meter on the line in question. Others accept a licensed engineer's affidavit estimating consumption. A few allow the credit based on equipment specifications alone. Spending money on installation before confirming your utility's documentation requirements is a costly mistake.
Second, rule out other billing problems. Before attributing a high water bill to legitimate use, it's worth investigating whether there's a meter malfunction, a billing error, or a hidden leak. We've seen accounts where a property was billed for a neighbor's consumption, or where a corroded meter was registering usage that never occurred. A professional meter inspection and bill audit should always come first.

Check these before installing a deduct meter:

- Is your main meter functioning correctly and reading accurately?- Are there any hidden leaks in supply lines, irrigation systems, or mechanical rooms?- Has your utility confirmed what documentation they require for a sewer credit?- Is your usage history consistent, or did the overbilling start after a renovation or equipment change?

The Step-by-Step Path to Recovering Sewer Overcharges
1. Audit your current water and sewer bills. Compare your historical usage against consumption norms for your building type. Sudden spikes, implausible averages, and charges that don't match your metered read are all red flags that warrant investigation.
2. Identify all non-sewered water uses. Document every piece of equipment or system on your property that consumes water without discharging it to the sewer — cooling towers, irrigation lines, process equipment, car washes, and so on.
3. Contact your local utility before doing anything else. Ask specifically what documentation is required to apply for a sewer credit. Get the answer in writing. This single step prevents most of the costly installation mistakes we see.
4. Have a licensed plumber install the appropriate metering. If a deduct meter is required, it must be installed correctly and often inspected by the utility before any credit is applied. In NYC, this work requires a licensed master plumber.
5. Submit your credit application with supporting documentation. Depending on your utility, this may include meter reads, equipment specs, engineering certifications, or affidavits.
6. Request retroactive credit where applicable. In many cases, credits can be applied retroactively to prior billing periods. Don't assume the utility will do this automatically — you typically need to request it.

Why Sewer Overcharges Go Undetected for Years
Most property owners see their water and sewer bills as a single line item and accept the charge at face value. Utility bills are complex, issued monthly, and rarely scrutinized against consumption benchmarks. Sewer credits require proactive application — utilities don't automatically give them to you. And because the error accumulates slowly, it rarely triggers the kind of alarm that a sudden spike in electric cost would.
This is especially true for properties without cooling tower meters, where evaporative water loss from HVAC systems is substantial but invisible on a standard bill. A 300-ton cooling tower can lose tens of thousands of gallons to evaporation per month — water that is charged to your sewer account by default unless you take action to document and exclude it.
We regularly work with property managers who have been carrying avoidable sewer overcharges for three, five, even eight years before someone flags it for review. The recoverable amount at that point can be significant — but only if the right documentation is in place and the retroactive claim is made correctly.

How Ashokan Helps NYC Properties Recover What They're Owed
Ashokan Water Services has spent over 27 years working with residential, commercial, and institutional properties across New York City. Our team of licensed master plumbers and utility billing specialists combines physical meter expertise with deep knowledge of DEP billing rules, credit programs, and audit procedures.
Our water bill audit service is designed specifically to identify recoverable overcharges. We review your billing history, assess your metering infrastructure, identify non-sewered uses that may qualify for credits, and handle the documentation and submission process on your behalf. We work on a contingency basis — we're only compensated when we find and deliver savings.
If a deduct meter is the right solution, our licensed master plumbers handle installation, inspection coordination, and filing with the relevant agencies. If the problem is a malfunctioning meter, a billing error, or a hidden leak, we diagnose and resolve that too.

The Bottom Line for NYC Property Owners
Sewer overcharges are one of the most consistently recoverable utility costs for commercial properties — but only if you know where to look and how to document the claim. A separate deduct meter can be an excellent investment, but it's not always the first step. The right starting point is a comprehensive review of your current billing, your metering infrastructure, and your utility's specific credit requirements.
Don't spend money on meters and installations before you know what your municipality requires. And don't leave recoverable credits on the table because the application process feels opaque. That's exactly what Ashokan is here for.

Ready to find out if you're overpaying? Request a free consultation