Your inspection report’s water heater notes aren’t all the same kind of note. A missing, corroded, or badly piped TPR valve is a genuine defect, and so is an expansion tank that’s rusting, leaking, or hanging without support. Both are worth a repair request no matter how old the tank is. The unit’s age by itself isn’t a defect. And if the report says nothing about the anode rod, nothing was missed — that part sits outside what a standard visual inspection checks.
That distinction decides where your leverage goes. React to every water heater line the same way and you’ll either burn a repair request asking a seller to replace a working tank because of its age — an easy request to refuse — or skim past a real safety defect that has nothing to do with age.
A water heater inspection is a visual exercise from start to finish. Two of these three findings are visible from outside the tank. One isn’t visible at all without opening it. That’s the whole reason they earn different responses from you.
Three Water Heater Findings, Side by Side
Here’s the short version, laid out by what each component does and whether an inspector can see it. Keep this next to the water heater section of your report while you and your agent sort the repair requests from the planning notes.
| Finding in the report. | What the component does. | Part of a standard visual inspection? | When it counts as a defect. |
|---|---|---|---|
| TPR valve. | It releases water on its own if pressure or temperature inside the tank passes safe levels. | Yes. The valve and its discharge pipe are both visible. | It’s missing, corroded, leaking, or piped so it can’t discharge safely. Age doesn’t matter. |
| Expansion tank. | It absorbs the extra volume created when water heats up and expands. | Yes. Location, support, corrosion, and leakage are all visible. | It’s corroded, leaking, or poorly supported. A missing tank is a question to ask. |
| Anode rod. | It corrodes on purpose so the tank’s lining doesn’t. | No. Reaching it means opening the tank at a plug. | Not rated either way. Silence in the report is normal here. |
The TPR Valve Is a Safety Device, Not Just a Fitting
Think of a TPR valve as the fuse on a sealed tank of heated water. InterNACHI’s technical reference on TPR valves and discharge piping describes these as safety devices “designed to automatically release water in the event that pressure or temperature in the water tank exceeds safe levels.” That’s the entire job. Nothing else on the appliance does it.
So when a report flags the valve, it’s flagging the one part that’s supposed to act when something else has already gone wrong. A compromised valve on a nearly new water heater is still a compromised valve.
The valve is only half of what your inspector is looking at. It has to connect to a discharge pipe that can survive what comes out of it — an approved material rather than ordinary PVC, which can melt. The pipe shouldn’t be narrower than the valve’s outlet. It should drain downhill by gravity, with no trap holding water in it. And it should end at a visible air gap instead of tying straight into a drain, so that a discharge is something a person can actually see.
All of that is observable and photographable without taking anything apart, which is why it belongs in a written report as a finding rather than a footnote. Your inspector documents the condition. A qualified plumber makes the correction. Those are two different jobs, and the report’s role is to tell you which one the house needs.
An Expansion Tank Either Does Its Job or It’s Missing
Water takes up more room when it’s hot. In a closed system, that extra volume has nowhere to push back to. An expansion tank is the space it pushes into instead.
The inspection industry’s own explainer on water heater expansion tanks describes one as “a metal tank connected to a building’s water heating appliance designed to accommodate fluctuations in the volume of a building’s hot water supply system,” and it’s direct about the stakes: “Expanding water volume in a closed system can create dangerously high water pressure.”
The same reference names what an inspection looks at. The tank “should be inspected for proper location and support, corrosion and leakage.” Every item on that short list is visible. A tank sagging off its connection, rust blooming at a seam, a damp stain on the floor underneath — those are report-worthy findings, and none of them care how old the water heater is.
What if your report doesn’t mention an expansion tank at all? There are two innocent explanations: the house doesn’t have one, or the system isn’t closed. Expansion tank requirements vary by jurisdiction, and many but not all areas now require one. So don’t read silence as a problem, and don’t read it as a clean bill either. Ask your inspector what was at the water heater, and let a plumber say whether the setup calls for a tank.
The Anode Rod Isn’t Part of a Standard Visual Inspection
The anode rod is a sacrificial part. It’s a metal rod suspended inside the tank that corrodes on purpose, so the corrosion happens to the rod instead of the tank’s lining. Once it’s spent, the tank starts absorbing that damage itself. It matters, and it’s invisible from the outside.
Checking it means opening the tank at a plug and drawing the rod out. That’s hands inside the appliance. A standard home inspection is non-invasive by design — visual, with equipment left the way it was found — so an inspector doesn’t grade a part that can’t be seen without disassembly. Its absence from your report is the expected outcome, not a gap in the work.
This is the same boundary behind what a standard home inspection doesn’t cover, just drawn at a smaller scale: a whole system left out versus one part inside a system your inspector did examine. If you want the rod evaluated, that’s a plumber’s service call, ordered separately and read separately from the inspection report.
Your Water Heater’s Age Still Isn’t a Defect by Itself
An age note is real information. It just isn’t a finding. The report records the age because you need it to plan, and planning is a different exercise from negotiating repairs — there’s a fuller look at planning around the ages your report already records if that’s where your head is. An inspector who writes down that a unit is fifteen years old hasn’t called it defective. They’ve told you where it sits in its service life.
Sellers get this wrong from the opposite direction. A water heater that works, with its age documented and no condition findings attached, isn’t a reason to replace anything before listing. A corroded TPR valve or a rusting expansion tank is worth addressing either way, because the buyer’s inspector will see the same thing you did.
Four Report Lines and What to Do With Each
A corroded TPR valve on a five-year-old unit
Make the repair request. The valve’s condition is the finding, and the tank’s age has no bearing on it. A young water heater with a compromised safety device is exactly the case this distinction exists for.
A fifteen-year-old water heater with nothing else noted
Don’t spend a repair request here. Write it on your post-closing planning list and move on. If you want a read on how much service life is left, that’s a plumber’s evaluation, not a negotiating point.
No mention of an expansion tank anywhere in the report
Ask before you assume. Your inspector can tell you what was present at the water heater and what the photos show. From there, a plumber can say whether this particular system needs a tank.
A seller’s pre-listing report that didn’t flag the water heater
Useful, but not a substitute for your own. If you’re buying, get your own inspection and your own written report. A pre-listing report captures an earlier day, and a valve or a tank fitting can change condition between one visit and the next.
Where This Framework Runs Out
A visual inspection is one day’s observation. A TPR valve that weeps intermittently, or a fitting that only seeps under a particular demand, can look sound during the visit. The report describes what an inspector could see and operate at the time. It isn’t a guarantee of how the appliance will behave later.
It also doesn’t replace specialized diagnosis. Anode rod condition, scale inside the tank, remaining service life — those answers come from a plumber with the tank opened and the right tools. A report that stays quiet on them is being accurate about its own scope rather than incomplete.
And all of this assumes you have a photographed report in hand to read. The water heater is already one of the systems Inspection Professionals documents with photos in a full home inspection, so a buyer or seller isn’t choosing between getting it inspected and skipping it. The open question is only how to read what the report says about it.
Get the Water Heater in Writing, With Photos
A report you can act on has to be specific at the water heater: the valve, its discharge piping, the expansion tank’s support and condition, and the unit’s age written down for planning. A regular inspection examines the roof, attic, insulation, walls, ceilings, floors, windows, doors, foundation, basement, electrical system, plumbing, HVAC, water heater, garage, and exterior grading. Every finding is documented with photos in a detailed report delivered within 24 hours, so you have a complete picture before making any decisions.
Buying or selling in Bucks County, Montgomery County, Philadelphia, or Delaware County? You can contact Inspection Professionals about a full, written inspection of the property. Then sit down with the report, separate the defects from the planning notes, and take your position from documentation instead of guesswork.