What to know
- Major manufacturers condition their warranties on documented maintenance — no service records can mean no coverage.
- Tankless is the strictest: heat exchangers are warranted 10–15 years but conditioned on annual flushing/descaling.
- Some tankless manufacturers also require water hardness below ~7 grains per gallon and will void coverage above ~12 GPG.
- Tank-style warranties hinge on sediment flushing and anode-rod inspection — a corroded-through anode rod is reportedly the single most common reason claims get denied.
Tankless: the strictest maintenance requirements
Tankless manufacturers commonly warrant the heat exchanger for 10–15 years, but condition that coverage on annual flushing and descaling. If the exchanger fails from scale buildup and the homeowner has no proof of maintenance, the claim gets denied. Some brands go further and require water hardness below roughly 7 grains per gallon, voiding coverage above about 12 GPG — which makes water treatment part of protecting the warranty in harder-water pockets of our region.
Tank-style: sediment and the anode rod
Traditional tank warranties hinge on two things: flushing sediment and inspecting the sacrificial anode rod. Sediment blankets the bottom of the tank, overheating the steel and popping like popcorn as water boils beneath it. The anode rod corrodes intentionally so the tank doesn't — but once it's consumed, the tank itself starts rusting. Manufacturers can deny a tank-failure claim as 'lack of proper maintenance,' and a corroded-through anode rod is reportedly the single most common reason water-heater claims are denied.
What a professional flush includes
An Eco water-heater service is more than opening a drain valve:
- Full sediment flush (tank) or descaling circulation with pump and solution (tankless).
- Anode rod inspection and replacement recommendation when it's consumed.
- Temperature & pressure relief valve test — a stuck T&P valve is a genuine safety hazard.
- Combustion and venting check on gas units; element and thermostat check on electric.
- Documented service record you can keep with your warranty paperwork.
The payoff
Annual service protects the warranty, extends equipment life, keeps recovery fast, and lowers operating cost — scale and sediment force the unit to burn more energy for the same hot water. If your heater hasn't been flushed in years, start now: a documented maintenance history from today still strengthens any future claim.
Ready for the next step?
Talk to a licensed Eco pro — honest guidance and upfront pricing before any work begins.
Continue exploring
Common questions
How often should I flush my water heater?
Annually for both tank and tankless units — and that's not just our advice, it's what the manufacturer warranty terms from brands like Rheem, Bradford White, A.O. Smith, Rinnai, and Navien are built around. Homes with harder water may benefit from more frequent tankless descaling.
My water heater is 8 years old and has never been flushed. Is it too late?
Not necessarily — but the first flush should be done carefully by a professional, because years of sediment can clog valves or reveal existing corrosion. We'll assess the anode rod and tank condition honestly and tell you whether maintenance or planned replacement is the smarter spend.
Does hard water really void a tankless warranty?
Some manufacturers specify water-quality limits — coverage requirements below roughly 7 grains per gallon of hardness, with denial possible above about 12 GPG. A simple hardness test tells you where you stand, and a softener or filtration system protects both the heater and the warranty.