Why Is My Wastewater Bill So High? 7 Causes & Fixes

Your wastewater bill is high because the utility calculates your sewage charges based on your water usage—typically during winter months—and factors like running toilets, leaky faucets, irrigation systems counted toward sewer, or rate increases can all inflate that number significantly.

Most homeowners don't realize that wastewater charges aren't metered directly. Instead, your sewer bill is estimated from how much water enters your home, with the assumption that most of it eventually goes down the drain. Understanding this billing method—and the common culprits behind sudden spikes—is the key to getting your sewage bill back under control.

How Wastewater Billing Actually Works in 2026

Your sewer bill is calculated from your water meter readings, not from a separate sewage meter—meaning every gallon that enters your home is assumed to leave through the sewer system.

Most municipalities in the United States don't install meters on sewer lines. It would be expensive and impractical to measure outgoing wastewater directly. Instead, utilities use your water consumption as a proxy. The logic is straightforward: water that comes in must go out.

Here's where it gets interesting. Many utilities establish a "winter average" billing method. They take your water usage during the coldest months—typically December through February or January through March—and use that as your baseline sewer charge for the entire year. The reasoning is that you're not watering lawns or filling pools in winter, so that usage more accurately reflects indoor water that actually reaches the sewer.

If your winter usage was unusually high—say, you had houseguests over the holidays or a toilet was running undetected—that inflated number follows you all year. One bad winter can mean 12 months of elevated sewer bills.

7 Reasons Your Sewer Bill Suddenly Spiked

A sudden increase in your sewerage bill usually traces back to one of seven causes: hidden leaks, rate increases, billing errors, lifestyle changes, faulty fixtures, irrigation counted toward sewer, or changes to your winter average baseline.

Is a Running Toilet Driving Up Your Sewage Charges?

A toilet that runs continuously can waste 200 gallons per day—that's 6,000 gallons per month added to your water bill, and since the utility assumes all of it went down the sewer, your wastewater charges climb right alongside. The tricky part is that many running toilets are silent. The flapper valve deteriorates slowly, letting water trickle from the tank to the bowl without any audible flow.

To test for a silent leak, drop food coloring into your toilet tank before bed. If the bowl water is colored by morning without anyone flushing, your flapper needs replacement. It's a $10 part and a 15-minute fix that could save you $50 or more per month.

Did Your Utility Raise Wastewater Rates?

Sewer infrastructure is expensive to maintain and upgrade. Aging pipes, EPA mandates, and treatment plant improvements all require funding. According to the American Water Works Association, water and wastewater rates have increased an average of 3-5% annually over the past decade, with some municipalities implementing double-digit increases to address infrastructure backlogs.

"Many utilities are facing a significant funding gap for necessary infrastructure improvements. Rate increases are often the primary mechanism to close that gap." — American Water Works Association

Check your bill for any rate change notices. They're often buried in fine print or included as bill inserts that are easy to miss.

Is Outdoor Water Use Being Charged to Your Sewer Bill?

Here's a frustrating quirk of wastewater billing: water that never reaches the sewer can still be counted toward your sewage charges. If you fill a swimming pool, water your lawn, or wash your car, that water evaporates or soaks into the ground—but the utility may still bill you for treating it as sewage.

Some municipalities offer an "irrigation meter" or "deduct meter" that separately measures outdoor water use and excludes it from sewer calculations. Installing one costs $500 to $1,500 upfront but can pay for itself within a year or two if you have significant outdoor water use.

Could a Billing Error Be the Culprit?

Meter misreads happen. Estimated bills during periods when the meter couldn't be accessed can be wildly inaccurate. Data entry errors occur. Accounts sometimes get confused with neighboring properties.

Request an itemized bill and compare it to previous months. Look for:
- Sudden jumps that don't match your actual usage patterns
- Estimated readings instead of actual readings
- Charges for services you don't receive
- Incorrect account information

If anything looks off, call your utility's billing department. Most will investigate and adjust if an error is found.

Did Your Household Water Use Change?

Sometimes the explanation is mundane. More people in the house means more showers, toilet flushes, and loads of laundry. Working from home increases daytime water consumption. A new washing machine or dishwasher might use more water than your old one—or less, which could explain a welcome decrease.

Think through any changes in your household over the past few months. Even temporary changes during your utility's winter averaging period can lock in higher rates for the whole year.

Are Hidden Leaks Wasting Water You're Paying to Treat?

Beyond toilets, leaks can hide in many places: under slab foundations, in walls, at outdoor spigots, or in supply lines to appliances. A pinhole leak in a supply line can drip constantly without any visible sign until water damage appears.

Check your water meter while all water fixtures are off. If the dial is still moving, water is flowing somewhere. Your utility may offer leak detection services, or you can hire a plumber with specialized equipment to locate hidden leaks.

Also Read: Why Is My Hot Water Cold? 9 Causes & How to Fix Them

Was Your Winter Average Unusually High?

If your sewer bill jumped at the start of a new billing year, check whether your winter average was recalculated. A winter with houseguests, a leak you've since fixed, or unusually cold weather that kept you doing more laundry can inflate your baseline.

Some utilities will recalculate your winter average if you can demonstrate that abnormal circumstances caused the spike. You may need to show a repair receipt proving a leak was fixed or provide documentation of temporary occupancy changes.

How to Read Your Wastewater Bill Correctly

Understanding what each line item means on your sewer bill is the first step toward identifying whether you're being overcharged.

Wastewater bills vary by municipality, but most include these components:

The volumetric charge is where high usage hits hardest. One CCF (centum cubic feet) equals 748 gallons. If your rate is $8 per CCF and you used 10 CCF last month, your volumetric charge alone is $80—before any base fees or surcharges.

Practical Ways to Lower Your Sewage Bill in 2026

Reducing your wastewater charges comes down to two strategies: use less water inside your home, and make sure outdoor water use isn't counted toward your sewer bill.

Fix Leaks Immediately

Every drip costs money twice—once on the water side, once on the sewer side. A faucet that drips once per second wastes 3,000 gallons per year. Prioritize:
- Toilet flappers and fill valves
- Dripping faucets and showerheads
- Supply lines to washing machines, dishwashers, and ice makers
- Outdoor hose bibs

Install Water-Efficient Fixtures

Modern low-flow toilets use 1.28 gallons per flush versus 3.5 or more for older models. WaterSense-labeled showerheads use 2.0 gallons per minute or less without sacrificing pressure. These upgrades reduce both your water and sewer bills.

Request an Irrigation Meter

If you have substantial outdoor water use—lawn irrigation, pool maintenance, car washing—contact your utility about installing a separate meter. The installation cost is usually recovered within 18-24 months through lower sewer charges.

Appeal Your Winter Average

If your winter average was calculated during an abnormal period, request a recalculation. Bring documentation:
- Plumber's invoice showing a leak was repaired
- Evidence of temporary guests or occupancy changes
- Proof of a one-time water use event (pool fill, pressure washing)

"Customers should always review their bills and contact the utility if they believe the winter quarter average doesn't reflect their typical usage." — EPA WaterSense Program

Check for Bill Assistance Programs

Many utilities offer low-income assistance, senior discounts, or hardship programs that reduce sewer bills. Some have payment plans or budget billing options that smooth out seasonal variations.

Also Read: Why Is My Toilet Bubbling When I Shower? 5 Causes & Fixes

When to Contact Your Utility Company

If you've checked for leaks, reviewed your bill for errors, and still can't explain the increase, it's time to call your utility's customer service department.

You have the right to:
- Request a meter accuracy test (usually free)
- Receive an itemized breakdown of all charges
- Ask how your winter average was calculated
- Apply for a bill adjustment due to documented leaks
- Dispute estimated readings

Keep records of all communications. If your utility is unresponsive, your state's public utility commission can often intervene.

Also Read: Why Is My Water Heater Beeping? 6 Causes & Quick Fixes

In Short

Your high wastewater bill almost always traces back to how the utility calculates your sewer charges—typically from water usage, not actual sewage output. Running toilets, hidden leaks, outdoor irrigation being counted toward sewer, rate increases, and inflated winter averages are the most common culprits. Fix leaks promptly, consider an irrigation meter for outdoor use, review your bill for errors, and don't hesitate to challenge your winter average if circumstances warrant it. A few targeted fixes can often drop your sewage bill by 20-30% or more.

What You Also May Want To Know

Why is my sewer bill higher than my water bill?

Sewer service often costs more than water delivery because wastewater treatment is more complex and expensive than water purification. Treatment plants must remove solids, chemicals, bacteria, and nutrients before discharging water back into the environment. Infrastructure costs are also substantial—sewer pipes are larger, must handle solids, and require lift stations in flat terrain. Additionally, many utilities charge sewer rates at 100% or more of water usage, compounding the cost difference.

Can I get a sewer credit for filling my swimming pool?

Many utilities offer one-time sewer credits for pool fills if you notify them in advance. You typically need to provide the pool's gallon capacity and request the adjustment before filling. Some utilities require a separate meter reading before and after. Contact your utility's customer service before filling to understand their specific process—retroactive credits are harder to obtain.

Why did my sewer bill go up when I haven't changed my water usage?

Rate increases are the most common explanation when bills rise without corresponding usage changes. Your utility may have implemented new rates, adjusted the winter average calculation, or added infrastructure surcharges. Review your bill for any notices about rate changes. Also check whether your account switched from estimated to actual readings—a correction can cause a sudden jump even if your real usage stayed consistent.

Does a leaky faucet really affect my sewer bill that much?

Yes, because you're charged twice for that wasted water. A faucet dripping at one drop per second wastes about 3,000 gallons annually. At typical combined water and sewer rates of $10-15 per 1,000 gallons, that single drip costs $30-45 per year. Multiple leaks or a running toilet can easily add $50-100 monthly to your combined bills.

How do I know if my water meter is accurate?

Request a meter test from your utility—most provide this service free once per year. The meter is tested against calibrated equipment to verify accuracy. If the meter is found to be over-registering, the utility will typically adjust your recent bills and replace the meter. You can also compare meter readings to known water use—fill a 5-gallon bucket and check if the meter registers exactly 5 gallons.

Reviewed and Updated on May 3, 2026 by Adelinda Manna