Water heater repair & replacement in Knoxville, TN.
No hot water this morning? Rusty water, popping sounds, or a puddle under the tank? Hard Knox Plumbing repairs and replaces standard tank water heaters across Knoxville and everywhere within 25 miles — often the same day you call.
Licensed, insured technicians. Upfront pricing before work starts. Warranty on every install. And a real person answers the phone 24/7, because water heaters don’t fail on a schedule.
Is it time?
Six signs your water heater is about to quit.
Most water heaters warn you before they fail. Catching it early is the difference between a scheduled replacement and a flooded floor with an emergency callout on top.
- Hot water runs out fast — sediment is stealing tank capacity, or an element has failed.
- Rusty or metallic-tasting hot water — the tank lining or anode rod is corroding.
- Popping, rumbling, or banging — hardened sediment on the tank floor.
- Water around the base — could be a valve, could be the tank. Don’t wait to find out.
- Bills creeping up — the unit is working harder to deliver the same hot water.
- It’s 10+ years old — you’re on borrowed time. Replace it on your terms.
Water on the floor right now? Shut off the cold water supply valve on top of the heater, then call 865.765.8946. We’re open 24/7.
Standard Water Heater Services
Repair, replace, or maintain — whatever your tank needs.
Diagnosis & repair
Thermostats, heating elements, thermocouples, gas valves, pilot assemblies, T&P valves, and supply connections — repaired properly, not band-aided.
Full replacement
Old unit drained and hauled away, new tank installed to current code with expansion tank, drain pan, and correct venting.
Annual flush & tune-up
Sediment flushed, anode rod checked, temperature and pressure verified. The single best thing you can do for tank life in hard-water country.
24/7 emergency response
Burst tank or total hot-water loss on a Sunday night? We answer, and we come out — no premium-hour runaround.
What to Expect
How a water heater replacement goes with us.
Most replacements take two to three hours from arrival to hot water.
Straight diagnosis
We test the unit and tell you whether it’s a repair or a replacement — with the reasoning, so you can make the call yourself.
Upfront price
You get an itemized price for parts, labor, permit, and haul-away before we touch a wrench. No hourly surprises.
Clean install
Drop cloths down, old tank drained and carried out, new unit set, connected, and brought up to current code.
Test & walkthrough
We verify temperature, check for leaks, register your manufacturer warranty, and show you the shutoff before we leave.
A dead water heater is a bad time for a big bill.
That’s why we offer financing. Get the replacement you need now and spread the cost into manageable monthly payments — with the same upfront pricing and full warranty either way.
Common Questions
Water heater questions, answered.
How much does a new water heater cost in Knoxville?
Installed price depends on tank size, fuel type (gas or electric), the brand you choose, and whether your current setup needs code updates like a new expansion tank, drain pan, or venting. We give you a firm, itemized price before we start — and that price is what you pay. Financing is available if you’d rather spread it into monthly payments.
How long do water heaters last?
A standard tank water heater typically lasts 8–12 years. Knoxville’s hard water shortens that when the tank isn’t flushed annually, because sediment settles on the bottom and forces the burner or element to work harder. If your unit is over 10 years old and starting to act up, replacing it on your schedule is far cheaper than replacing it after it floods your garage.
Can you replace my water heater the same day?
Usually, yes. We stock common residential tank sizes and can often diagnose and replace on the same visit — especially if you call early. If a replacement has to wait, we’ll tell you straight and give you a firm appointment window rather than a vague promise.
Should I repair or replace my water heater?
Repair usually makes sense if the unit is under 8 years old and the failure is a thermostat, element, thermocouple, or valve. Replace if the tank itself is leaking, the unit is past 10–12 years, or repair costs approach half the price of a new one. We tell you which situation you’re in and let you decide — no scare tactics.
Why is my water heater leaking?
Leaks from fittings, the drain valve, or the T&P relief valve are often repairable. Water seeping from the bottom of the tank itself means the inner lining has corroded through, and the unit needs replacing — there’s no patch for that. Either way, shut off the water supply to the heater and call us at 865.765.8946; we answer 24/7.
What size water heater do I need?
As a rule of thumb: 40 gallons for 2–3 people, 50 gallons for 3–4, and 75+ gallons or a tankless unit for larger households and homes with big soaking tubs. Recovery rate matters as much as capacity, so we look at how your family actually uses hot water rather than just matching whatever was there before.
Do you flush and maintain water heaters?
Yes. An annual flush removes the sediment that East Tennessee’s mineral-heavy water leaves behind, protects efficiency, and extends the life of the tank. It’s a standalone service, and it’s included every year for Hard Knox Home Club members along with an anode rod check.
Recommended by your neighbors.
“My cost was exactly what he told me over the phone. He was on time, cleaned up after the repair and was very courteous. Hard Knox Plumbing will always be my first call.”
“As I expected, my call was answered by someone who actually knew what my problem was. Danny was able to work me in today.”
“It was an amazing service. They were on time, on budget and great to work with. Very knowledgeable, very friendly, and a reasonable price.”
From the blog
Straight answers on water heaters.
Related Services
Consider these alongside your new heater.
Tankless Water Heaters
Endless hot water, lower energy bills, and a 20+ year lifespan.
Learn more →Water Filtration Systems
Softer, cleaner water at every tap — and less scale in your pipes.
Learn more →Hard Knox Home Club
Annual inspection, priority scheduling, and member-only repair discounts.
Learn more →Your Local Water Heater Pros
Same-day water heater service across Knox County.
Hard Knox Plumbing works out of 3414 Henson Rd C, Knoxville, TN 37921, and we’re on the road across Knoxville, Farragut, Hardin Valley, Lenoir City, Oak Ridge, Loudon, Alcoa, and Maryville every day. Our trucks carry common tank sizes and parts, so most calls end with hot water the same visit.
Call 865.765.8946 — a real person answers 24/7, including nights, weekends, and holidays.
No hot water right now?
We're open 24/7. Call us right now.
A failed water heater can’t wait for Monday. A Hard Knox plumber answers around the clock — nights, weekends, and holidays.