Understanding Your Water and Wastewater Utility Bill
Why the wastewater portion can triple, how metered water affects both charges, and what to check before assuming the bill is wrong.
For KUB residential customers, wastewater charges are based on metered water consumption. That means an unexplained increase in water use can raise both the water and wastewater portions of the bill. A silently running toilet is one of the first things to check: water can leak from the tank into the bowl around the clock, enter the sewer system, and register at the water meter even when no one notices it. Other possibilities include irrigation, a service-line or hidden pipe leak, a dripping fixture, a water heater relief valve discharging, an automatic appliance, a longer billing period, or a rate change.
Why This Matters
A homeowner may focus on the wastewater line because it tripled, but the wastewater charge may be following the same metered-water increase shown elsewhere on the bill. Looking at consumption—not only the dollar amount—helps separate a plumbing problem from a pricing or billing issue. Finding the cause quickly can limit property damage and preserve the documentation needed if the utility offers a qualifying leak or watering credit.
How It Generally Works in the Knoxville Area
Start with usage, not dollars: Compare the current and previous bills for CCF or gallons used, meter readings, and the number of days in each billing period. KUB bills water in CCF; one CCF equals 100 cubic feet, or approximately 748 gallons. A higher dollar amount with similar usage may point toward rates, fees, or billing-period differences. A large usage increase points toward additional water use or a leak. Why wastewater can rise too: KUB states that residential wastewater rates are based on water consumption. There normally is not a second meter measuring every gallon that goes down a household drain. If the water meter records more usage, the wastewater charge can also increase under the utility's billing rules. Customers served by another water or wastewater provider should verify that provider's calculation method. Probable plumbing causes: • Running toilet or silent tank-to-bowl leak — commonly a flapper or flush-valve sealing issue, chain interference, fill-valve problem, or water entering the overflow tube. Because the water continuously enters the drain, it can raise both charges. • Irrigation, sprinkler leak, pool filling, pressure washing, or frequent outdoor watering. Outdoor use may still affect wastewater billing unless the utility applies a watering credit or the property has a qualifying separate irrigation meter. • Underground service-line, slab, crawlspace, wall, or other hidden supply leak. • Dripping faucet, showerhead, hose bibb, or appliance connection. • Water heater T&P relief valve or another discharge path running to a drain or outside. Do not cap or disable a relief valve. • Water softener stuck in regeneration, reverse-osmosis waste flow, humidifier, ice maker, or another automatic water-using device. • More occupants, guests, laundry, showers, or other real usage changes. Non-plumbing possibilities: A longer billing cycle, an estimated or corrected reading, a changed rate or fee, a prior balance, or a different service classification can change the amount due. The utility must explain account-specific billing details. Credits after a repair: KUB currently describes watering and leak-credit programs. Eligibility, credit percentage, thresholds, documentation, and deadlines depend on the circumstances. Keep the repair invoice, photos, dates, and proof that the leak was corrected, then contact KUB promptly. A credit is not guaranteed.
What the Homeowner Can Check
- Compare CCF or gallons used with the same period last year and with the previous bill—not just the total dollars
- Check the billing dates and number of days, and look for estimated or corrected meter readings
- Test every toilet with food coloring in the tank; wait without flushing and watch for color entering the bowl
- Look inside each toilet tank for water flowing into the overflow tube or a fill valve that never completely shuts off
- Turn off all known water uses and watch the meter or KUB usage portal for continued flow
- Check irrigation, hose bibbs, crawlspaces, the water-heater discharge pipe, appliances, softeners, and the yard for unexplained water
- Save the bill, repair invoice, photos, and repair date in case the utility requests proof for a possible credit
Who to Contact
The Classic Plumber
If usage increased or the meter continues recording flow with everything off, we can check toilets, fixtures, interior piping, and concealed or underground leak possibilities.
Learn moreKUB Customer Service
For account-specific meter readings, billing calculations, current wastewater rules, or possible watering and leak credits. KUB lists 865-524-2911 for customer service.
Visit siteWhat Not to Do
- Do not assume a tripled wastewater charge means the sewer line is leaking; a sewer-line leak generally does not make the water meter record additional water
- Do not ignore a running toilet because it is quiet—a silent tank-to-bowl leak can continue all day and night
- Do not cap, plug, or disable a water-heater relief valve that is discharging
- Do not promise or rely on a utility credit until the utility confirms eligibility
Still not sure who is responsible or what to do next?
Ask our AI Plumber — describe the problem and get guidance on whether it is likely on your side or the utility side.
Ask the AI PlumberVerify current requirements directly with the applicable authority.
Requirements may differ depending on whether the property is inside the City of Knoxville, elsewhere in Knox County, or served by another utility. Homeowners should verify current requirements with the applicable permitting authority before beginning work.
Common Questions
Why did my wastewater charge triple?
For KUB residential customers, wastewater charges are based on water consumption. If metered water use increased sharply, the wastewater charge can rise with it. Compare CCF or gallons and billing days, then check toilets and the meter before assuming the bill is incorrect.
Can a running toilet really cause that much usage?
Yes. A toilet can leak silently from the tank into the bowl continuously. Check for water entering the overflow tube and perform a food-coloring test. The exact amount depends on the failure and how long it ran.
Would a sewer-line leak make my water bill higher?
Usually no. A damaged gravity sewer lateral does not normally cause the water meter to record more incoming water. A higher metered-water reading points instead toward actual use or a leak in the pressurized water system or a fixture.
Can KUB adjust the bill after a leak is repaired?
KUB currently publishes watering and leak-credit programs, but qualifications, documentation, deadlines, and credit amounts vary. Keep proof of repair and contact KUB promptly at 865-524-2911 to ask whether the account qualifies.
What if my water usage did not increase?
If CCF or gallons are similar but the dollar amount increased, compare billing days, rates, service charges, estimated or corrected readings, and any prior balance. Contact the utility for an account-specific explanation.
If the problem involves your home's plumbing, The Classic Plumber can help.
We diagnose before we recommend — and we tell you when the issue is on the utility's side.