Water heaters are among the most inspectedand most defect-pronecomponents in any home. A single missed issue can mean property damage, safety hazards, or unhappy clients. This guide covers every documentation scenario: TPR valve defects, venting problems, leaks, age assessment, and the exact narratives that protect you and inform your clients.

15+ Common Defects
20+ Sample Narratives
8 Photo Tips
8-12 Year Lifespan

Water Heater Types at a Glance

Different water heater types have different inspection priorities. Know what to look for based on the system you're evaluating:

Gas Tank

Critical Venting & Draft
Critical TPR Valve
Important Gas Supply
Important Combustion Air
Standard Sediment Trap
Typical lifespan: 8-12 years

Electric Tank

Critical TPR Valve
Critical Electrical Connection
Important Grounding
Important Tank Condition
Standard Expansion Tank
Typical lifespan: 10-15 years

Tankless

Critical Venting (Gas)
Critical TPR Valve
Important Error Codes
Important Scale Buildup
Standard Condensate Drain
Typical lifespan: 15-20 years

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TPR Valve: The #1 Safety Component

The Temperature and Pressure Relief (TPR) valve prevents catastrophic tank failure. A missing, defective, or improperly installed TPR valve is a serious safety hazard that requires immediate documentation.

TPR Discharge Pipe Requirements (IRC P2804.6.1)

Same diameter as valve outlet (typically ¾")
Terminate 2-6 inches above floor or drain
No valves, caps, or reducers in the line
Not trapped—must drain by gravity
Termination visible and observable
Approved materials only (copper, CPVC—NOT PVC)

Common TPR Valve Defects

Safety Hazard

Missing Discharge Pipe

No discharge pipe attached to TPR valve—hot water/steam would spray directly outward if activated.

Sample Narrative:

"The TPR valve discharge pipe is missing. If the valve activates, scalding water will spray horizontally, creating a burn hazard. Recommend installation of a properly sized discharge pipe by a licensed plumber."

Safety Hazard

Pipe Too Short / Terminated High

Discharge pipe terminates more than 6 inches above floor, increasing splash and burn risk.

Sample Narrative:

"The TPR discharge pipe terminates approximately 24 inches above the floor. Code requires termination within 6 inches of the floor to reduce injury risk. Recommend extension by a licensed plumber."

Repair Needed

Reducer Installed

Discharge pipe reduced in size—restricts flow and could prevent proper pressure relief.

Sample Narrative:

"The TPR discharge pipe has been reduced from ¾" to ½". This restriction could impede water flow during valve activation and reduce effectiveness of the safety device. Recommend correction."

Repair Needed

Improper Material (PVC)

PVC is not rated for hot water and may fail when TPR valve activates with 210°F+ water.

Sample Narrative:

"The TPR discharge pipe is PVC, which is not approved for hot water discharge (water may reach 210°F+). Recommend replacement with copper or CPVC by a licensed plumber."

Repair Needed

Trapped Discharge Pipe

Pipe has low point that would trap water, potentially allowing bacteria growth or freezing.

Sample Narrative:

"The TPR discharge pipe is trapped (has a low point). Trapped water can harbor bacteria and contaminate the system if backflow occurs. Recommend re-routing to drain by gravity."

Monitor

Valve Leaking/Weeping

Small amounts of water dripping from valve—may indicate failing valve or excessive pressure.

Sample Narrative:

"The TPR valve is weeping (slow leak observed). This may indicate a failing valve or excessive system pressure. Recommend evaluation by a licensed plumber."

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Gas Water Heater Venting & Backdrafting

Improper venting is one of the most dangerous water heater defects. Backdrafting allows carbon monoxide and combustion gases to spill into the living space—a potentially deadly situation that demands clear documentation.

Signs of Backdrafting

Moisture at Draft Hood Warm, moist air felt with hands cupped around hood
Soot/Scorching Dark stains on draft hood or nearby surfaces
Melted Plastic Deformed caps on water supply pipes
Mirror Test Mirror fogs when held near draft hood
Corrosion Rust on vent connector or draft hood

Common Causes

  • Improper vent pitch — Must slope upward ¼" per foot minimum
  • Vent connector too long — Excessive horizontal runs
  • Oversized flue — "Orphaned" water heater in furnace flue
  • Blocked/obstructed vent — Bird nests, debris, collapsed liner
  • Missing vent cap — Allows downdrafts
  • Insufficient combustion air — Tight house syndrome
  • Competing exhaust fans — Kitchen hoods, dryers pulling air
TESTING BOX

How to Test for Backdrafting

1 Let the burner run for 1-2 minutes to warm up
2 Cup hands around draft hood (don't touch—it's hot)
3 Feel for warm, moist air coming out = backdrafting
4 Optional: Hold mirror near draft hood—fogging confirms spillage

Pro Tip: Test under "worst case" conditions when possible—close windows, run exhaust fans. Some water heaters only backdraft when competing with other air-moving equipment.

Venting Defects to Document

Safety Hazard

Active Backdrafting

"The gas water heater was actively backdrafting at the time of inspection. Combustion gases were spilling into the living space—an immediate safety concern. Do not use until evaluated and corrected by a qualified HVAC technician."

Safety Hazard

Disconnected Vent

"The vent connector is disconnected from the flue. All combustion gases are venting directly into the utility room. Do not operate until repaired. Recommend immediate correction."

Repair Needed

Improper Pitch

"The vent connector has improper pitch (slopes downward toward flue). Minimum ¼" per foot upward slope required. This condition increases backdrafting risk. Recommend correction."

Repair Needed

Missing Vent Cap

"No cap installed at the vent termination. This allows rain entry and wind-induced downdrafts. Recommend installation of a listed vent cap."

Documenting Leaks & Tank Condition

Leaks are often the first visible sign that a water heater is nearing end of life. Document the location, severity, and likely cause:

TPR Valve Leak

Dripping from valve or discharge pipe. May indicate failing valve or excessive system pressure.

Action: Recommend plumber evaluation

Fitting/Connection Leak

Drip at water supply connections, unions, or fittings. Often repairable.

Action: Recommend repair by plumber

Drain Valve Leak

Dripping from drain valve at bottom of tank. Valve may need tightening or replacement.

Action: Recommend repair or cap

Tank Leak (Bottom)

Water pooling beneath tank with no other source identified. Internal corrosion—tank failure imminent.

Action: Recommend replacement

Determining Water Heater Age

Age is a critical factor in assessing remaining service life. Most tank water heaters last 8-12 years; knowing the age helps set client expectations.

Serial Number Decoding

Most manufacturers encode the date in the first 4 characters of the serial number:

Letter + Numbers (A-L = Month) Example: D152... = April 2015 A=Jan, B=Feb, C=Mar, D=Apr, etc.
YYMM Format Example: 1806... = June 2018 First 2 digits = year, next 2 = month
MMYY Format Example: 0619... = June 2019 First 2 digits = month, next 2 = year

Tip: Use the Building Intelligence Center or manufacturer websites to decode serial numbers for specific brands.

Age-Related Narratives

Within Lifespan

"The gas water heater was manufactured in 2019 (approximately 6 years old). No visible defects or leaks observed. Unit is within typical service life for this type of water heater."

Approaching End

"The electric water heater was manufactured in 2015 (approximately 10 years old). No active defects observed at this time; however, the unit is approaching the end of its typical service life (8-12 years for tank water heaters). Budget for replacement in the near term."

Beyond Lifespan

"The water heater was manufactured in 2009 (approximately 16 years old), which exceeds the typical 8-12 year service life for tank water heaters. While functional at the time of inspection, replacement should be anticipated."

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Photo Documentation Checklist

The right photos protect you and help clients understand issues. Capture these for every water heater:

1

Data Plate

Shows model, serial number, capacity, BTU rating. Essential for age verification.

2

Overall View

Full tank showing location, clearances, and general condition.

3

TPR Valve & Discharge

Show valve, full length of discharge pipe, and termination point.

4

Venting (Gas Units)

Draft hood, vent connector, and connection to flue.

5

Gas Supply (Gas Units)

Shutoff valve, sediment trap, flex connector.

6

Electrical (Electric Units)

Disconnect, wiring entry, grounding.

7

Base/Floor

Check for rust stains, moisture, or evidence of past leaks.

8

Any Defects

Close-ups of corrosion, leaks, or other issues found.

Frequently Asked Questions

Should I operate the TPR valve during inspection?

Most standards of practice do not require manually testing TPR valves, and many inspectors avoid doing so because: (1) The valve may not reseat properly afterward, causing a continuous leak; (2) This could be seen as damaging the property; (3) Visual inspection typically reveals most defects. If you do test it, inform the homeowner/seller beforehand.

How do I report a water heater without a data plate?

Document that the data plate is missing or illegible, which prevents age verification. Note: "Unable to determine water heater age—data plate missing/illegible. Age is a significant factor in assessing remaining service life. Recommend consulting with a plumber for evaluation."

Is a missing expansion tank a defect?

Expansion tanks are required on closed systems (where a backflow preventer or check valve prevents water from expanding back into the municipal supply). If the system is "open" (no backflow prevention), an expansion tank isn't required. Document presence or absence and note if system type is unclear.

What about tankless water heater TPR valves?

Tankless water heaters also require TPR valves, though they're often smaller and may be located differently. The same discharge pipe requirements apply: proper materials, no reducers, terminate within 6 inches of floor, drain by gravity.

How should I document rusty water from the tank?

Rusty or discolored hot water typically indicates internal tank corrosion or a failing anode rod. Document: "Rusty/discolored hot water observed. This may indicate internal tank corrosion, a depleted anode rod, or corroding supply pipes. Recommend evaluation by a licensed plumber."