Task 1: Flush the Tank
Draining several gallons of water through the tank's drain valve annually clears out sediment that has settled at the bottom before it has a chance to harden into the kind of stubborn buildup that reduces efficiency and causes the rumbling noise covered in our replacement signs guide.
How This Is Done Safely
Power or gas should be shut off first (for electric units, this prevents the heating element from activating while the tank is low on water, which can damage it; for gas units, this is a standard precaution), then the cold water supply is closed before opening the drain valve to release several gallons. Caution around hot water is important throughout this process, since the water coming out is at the tank's normal operating temperature.
Why Annual Frequency Matters
Sediment accumulates gradually with every heating cycle, and Arlington's moderately hard municipal water contributes mineral content that settles over time. An annual flush keeps this from ever accumulating to a level that meaningfully affects efficiency or unit lifespan, whereas skipping this for several years in a row allows buildup to harden into something a simple flush can no longer fully address.
Task 2: Test the Pressure Relief Valve
The temperature and pressure relief (T&P) valve is a critical safety component designed to release pressure automatically if the tank ever builds up dangerously excessive internal pressure — testing it confirms it will actually function if that scenario ever occurs, rather than assuming it works simply because it's never been triggered.
How to Test It
Lifting the valve's test lever briefly should release a distinct burst of water into the discharge pipe — this confirms the valve is functioning and not stuck or corroded shut. A valve that doesn't release any water when tested, or one that continues dripping steadily after the test rather than fully reseating, needs replacement, since a non-functioning safety valve is a real risk that shouldn't be left unaddressed.
Task 3: Check the Anode Rod
The anode rod is a sacrificial component, typically made of magnesium or aluminum, specifically designed to corrode instead of the tank's steel walls — it's essentially a decoy that attracts the corrosive reaction that would otherwise attack the tank itself directly.
Why This Is One of the Highest-Value Maintenance Steps
Once an anode rod has fully corroded away, the tank's own steel becomes the next target for the same corrosive process, meaningfully accelerating the countdown toward tank failure and leaks. Checking the rod's condition every couple of years, and replacing it when significantly eroded (typically when more than about half the rod's original core wire is exposed), is one of the most cost-effective ways to extend a tank's working life — a relatively inexpensive part protecting a much more expensive tank.
Recommended Interval
Every 2-3 years is a reasonable check interval for most households, sooner in areas with harder water that accelerates the corrosion process the rod is designed to absorb.
Additional Steps Worth Including
Visual Inspection for Leaks or Corrosion
A quick visual check around all fittings, connections, and the tank body itself for any sign of moisture, rust, or mineral deposits can catch a developing issue before it becomes an active leak.
Checking the Venting (Gas Units)
For gas water heaters, confirming the venting is properly connected and unobstructed is a straightforward visual check worth including as part of the annual routine, particularly relevant given the combustion safety considerations covered in our gas versus electric guide.
What You Can Reasonably Do Yourself vs. What to Have Professionally Done
Tank flushing and the pressure relief valve test are both reasonable DIY tasks for a moderately confident homeowner comfortable following instructions carefully around hot water and, for gas units, the pilot light. Anode rod inspection and replacement often benefits from professional handling, since the rod can be difficult to remove (particularly on an older unit where it may be somewhat seized) and improper reinstallation can cause its own issues. Many homeowners choose to bundle all three into a single annual professional maintenance visit rather than splitting the DIY-friendly tasks from the ones better left to a plumber.
Need a Plumber in Arlington?
Licensed, upfront, and available 24/7. Call (571) 202-6461 or request a free quote.
Frequently Asked Questions
Can I flush my own water heater tank?
Yes, with care — shut off power/gas first, and be cautious of hot water when opening the drain valve, which is at the tank's normal operating temperature.
How often should the anode rod be checked?
Every 2-3 years is a reasonable interval, sooner in areas with harder water that accelerates the corrosion process the rod is designed to absorb.
What happens if I never flush my water heater at all?
Sediment accumulates and hardens over years, reducing efficiency, causing the rumbling noise covered in our replacement signs guide, and generally shortening the tank's practical working life.
Is it normal for a little water to come out when I test the pressure relief valve?
Yes — a brief burst of water when the test lever is lifted confirms the valve is working correctly; continued dripping afterward, or no water release at all, indicates the valve needs replacement.
Does a tankless water heater need the same maintenance as a tank unit?
No — tankless units don't have sediment buildup or an anode rod in the same way, but they need periodic descaling to remove mineral buildup from the heating element instead.
How long does a full annual maintenance visit typically take?
Usually under an hour for a standard tank unit covering all the key tasks, assuming no issues are discovered that require additional work.