How Do You Read the Date on a Propane Tank? Complete Guide to Propane Tank Date Codes

Everything You Need to Know About Propane Tank Date Stamps-How to Read Manufacture and Requalification Dates, Why They Matter for Safety and Legal Compliance, When to Recertify or Replace Your Tank, and How to Find Date Codes on All Types of Propane Cylinders

Introduction: Why Propane Tank Dates Matter

Every propane tank has important date codes stamped into the metal that tell you when it was manufactured and when it needs to be recertified. Understanding how to read these dates is essential for safety, legal compliance, and knowing when to replace your tank.

Why propane tank dates matter:

🛡️ Safety - Tanks degrade over time; old tanks can be dangerous

⚖️ Legal Compliance - Using expired tanks may be illegal

💰 Cost Savings - Know when to recertify vs. replace

⏱️ Recertification Schedule - Know when your tank needs inspection

🔄 Exchange and Refill - Stations won't accept expired tanks

🏭 Manufacturer Warranty - Coverage depends on tank age

This comprehensive guide covers:

Where to find date codes on propane tanks

How to read manufacture dates

How to read requalification (recertification) dates

Tank recertification requirements by type

When tanks expire and need replacement

How to tell if a tank is safe to use

Differences between tank types and date formats

Frequently asked questions

Part 1: Where to Find Date Codes on Propane Tanks

Location of Date Stamps

Propane tank date codes are permanently stamped into the metal of the tank. The location depends on the type and size of the tank.

On Portable Cylinders (20 lb, 30 lb, 40 lb BBQ and RV Tanks):

Location: Tank Collar (the metal ring at the top of the tank)

What to Look For:

Look at the metal collar on top of the tank

The collar has various stamped information

Date codes are typically on the front or side of the collar

Dates are stamped as numbers, not printed

What Else Is on the Collar:

Manufacturer name

Tank capacity

"WC" (Water Capacity)

"TW" (Tare Weight)

"DOT" specification

Test pressure

Date of manufacture

On Large Stationary Tanks (120+ Gallons):

Location: Data Plate (metal nameplate attached to tank)

What to Look For:

Metal plate riveted or welded to tank

Usually on the tank end or side

Contains all tank specifications

Date of manufacture clearly marked

On Exchange Tanks (Blue Rhino, AmeriGas, etc.):

Location: Collar or Tank Body

What to Look For:

May have plastic wrapper with date

Date code still stamped on collar

Exchange companies track dates internally

Exchange tanks are always within recertification date

How Date Codes Are Formatted

Date codes are stamped as numbers, not written out as dates. Understanding the format is key to reading them correctly.

Common Formats:

Format 1: Month-Year Format (Most Common)

Example: 06-21 or 06 21

Means: June 2021 (manufacture date)

Format 2: Year-Month Format

Example: 21-06 or 21 06

Means: June 2021 (manufacture date)

Format 3: Quarter-Year Format

Example: 2Q21 or 2-21

Means: Second Quarter 2021 (April-June 2021)

Format 4: Year First, Then Month

Example: 21 06

Means: Year 2021, Month 06 (June 2021)

Important: Different manufacturers use different formats. Always check for context clues like "MFG DATE" or "MANUFACTURED" near the numbers.

Part 2: How to Read the Manufacture Date

Understanding Manufacture Date Stamps

The manufacture date (also called "birth date") tells you when the tank was made. This is the starting point for calculating when the tank needs recertification.

Step-by-Step Guide to Reading Manufacture Date

Step 1: Locate the Collar or Data Plate

On portable tanks: Look at metal collar on top

On large tanks: Look for metal data plate

Step 2: Identify the Date Code Area

Look for stamped numbers in format: MM-YY or YY-MM

May be near "MFG DATE", "MANUFACTURED", or "DATE"

If no label, look for the newest-looking stamp in date format

Step 3: Determine the Format

Two numbers separated by dash, space, or slash

First number could be month (1-12) OR year

Second number could be year OR month

How to Tell Which Format:

If first number is 1-12: Likely month-first format (MM-YY)

If first number is 13-99: Year-first format (YY-MM)

If first number is 00-12: Could be either-check manufacturer

Step 4: Interpret the Date

Example 1: "06-21"

Format: Month-Year (MM-YY)

Meaning: June 2021

Example 2: "21-06"

Format: Year-Month (YY-MM)

Meaning: June 2021

Example 3: "12-20"

Could be: December 2020 OR Year 2012, Month 20 (invalid)

Since month can't be 20, this is: December 2020 (MM-YY)

Example 4: "11-19"

Could be: November 2019 OR Year 2011, Month 19 (invalid)

Since month can't be 19, this is: November 2019 (MM-YY)

Common Manufacture Date Examples

What Manufacture Date Tells You

From manufacture date, you can calculate:

Tank Age: Current year - manufacture year

Initial Recertification Due: 12 years from manufacture (for most portable tanks)

Remaining Safe Life: Tanks typically last 25-30 years with proper recertification

Part 3: How to Read Requalification (Recertification) Dates

What Is Tank Requalification?

Requalification (also called recertification or retest) is a professional inspection that verifies a propane tank is still safe to use. After the initial certification period expires, tanks must be recertified.

Requalification Date Format

After a tank is recertified, a new date stamp is added indicating:

The date of recertification

The type of inspection performed

Who performed the inspection

Requalification Date Stamps:

Format: Usually follows MM-YY pattern with additional codes

Example Stamps:

E Stamp (External Visual Inspection):

Example: E 06-25

Meaning: External visual inspection performed in June 2025

Valid for: 5 years from date

S Stamp (Proof Test):

Example: S 03-23

Meaning: Proof test performed in March 2023

Valid for: 5-7 years (depending on test type)

V Stamp (Volumetric Expansion Test):

Example: V 09-24

Meaning: Volumetric expansion test in September 2024

Valid for: 5-10 years

R Stamp (Reheat Treatment):

Rare; indicates tank was heat-treated

Example: R 06-22

Where Requalification Dates Are Stamped

Location: Usually on the tank collar near the original manufacture date

What to Look For:

Additional date stamps near the original date

May have letter code (E, S, V, R) before date

Stamps from multiple recertifications may be present

Each recertification adds a new stamp

Reading Multiple Date Stamps

Tanks may have multiple date stamps if they've been recertified multiple times.

Example of Collar with Multiple Stamps:

code复制

[Original Manufacture] 06-12 [First Recertification - External Visual] E 06-24 [Second Recertification - Proof Test] S 03-29

Interpretation:

Manufacture: June 2012

First recertification: June 2024 (E = External Visual)

Second recertification: March 2029 (S = Proof Test)

Part 4: Recertification Requirements by Tank Type

When Does a Propane Tank Need Recertification?

Different tank types have different recertification schedules based on Department of Transportation (DOT) regulations.

Portable Cylinders (20 lb, 30 lb, 40 lb - DOT 4B, 4BA, 4BW)

Initial Certification: 12 years from manufacture date

After Recertification: 5, 7, or 10 years depending on inspection type

Timeline:

DOT-4E Cylinders

Initial Certification: 12 years from manufacture

Recertification: Every 5 years after initial recertification

High-Pressure Cylinders (for welding gases, etc.)

Initial Certification: 5 years from manufacture

Recertification: Every 5 years

Large Stationary Tanks (ASME Tanks)

Initial Certification: No expiration-ASME tanks don't require recertification

Requirement: Regular visual inspections by owner or propane supplier

Replacement: When visual inspection reveals damage, corrosion, or safety concerns

Motor Fuel Tanks (Forklifts, Vehicles)

Initial Certification: 12 years

Recertification: Every 5 years

Part 5: When Tanks Expire and Need Replacement

Tank Expiration vs. Recertification

Key Distinction:

Recertification: Renewing a tank's certification through professional inspection

Expiration: Tank is no longer safe and cannot be recertified

When a Tank Cannot Be Recertified

Tanks should be replaced (not recertified) if:

1. Age Exceeds Safe Life:

Most tanks have maximum safe life of 25-30 years

Even with recertification, tanks eventually become unsafe

Manufacturer guidelines indicate maximum life

2. Visible Damage:

Deep dents

Rust through (rust creates hole)

Fire damage

Structural damage

Damaged valve

3. Corrosion:

Significant surface rust

Pitting corrosion

Corrosion around welds

Corrosion on tank bottom

4. Valve Damage:

Broken or damaged valve

OPD valve not functioning

Cross-threaded valve

Valve leaks

5. Unknown History:

No date stamps visible

Cannot determine manufacture date

No way to verify age or recertification history

Maximum Tank Age by Type

Part 6: How to Tell If a Tank Is Safe to Use

Safety Checklist for Propane Tanks

Before using any propane tank, verify:

1. Check the Date Code ✅

Step 1: Find manufacture date on collar

Step 2: Calculate tank age

code复制

Current Year - Manufacture Year = Tank Age Example: Manufacture: 06-15 (June 2015) Current Year: 2026 Tank Age: 11 years

Step 3: Check if within certification period

Portable tanks: 12 years initial, then 5-10 years after recertification

If tank is 12+ years old and no recertification stamp → DO NOT USE

If tank is 25+ years old → Consider replacement

2. Visual Inspection ✅

Check For:

❌ Deep dents (more than 1/4" deep)

❌ Rust through (rust creating holes)

❌ Bulges or deformation

❌ Fire damage (discoloration, soot)

❌ Cracks in metal or welds

❌ Damaged collar or foot ring

3. Check the Valve ✅

Check For:

✅ OPD valve present (triangular handle)

❌ Broken or stuck valve

❌ Leaking from valve

❌ Cross-threaded connections

❌ Missing or damaged O-rings

4. Check for Recertification Stamps ✅

If Tank Is 12+ Years Old:

Look for recertification stamp on collar

E, S, or V stamp with date

If no recertification stamp → Tank is expired → DO NOT USE

5. Professional Inspection ✅

When in Doubt:

Take tank to propane professional

They can verify date and safety

They can recertify if eligible

They will condemn if unsafe

Part 7: Date Codes on Different Tank Types

BBQ Tanks (20 lb)

Tank Type: DOT 4B, 4BA, or 4BW

Date Location: Metal collar on top

Format: Usually MM-YY

Example: 06-21 = June 2021

Recertification: Required at 12 years, then every 5-10 years

RV Propane Tanks (30 lb, 40 lb)

Tank Type: DOT 4B, 4BA, or 4BW

Date Location: Metal collar (horizontal tanks) or data plate

Format: Usually MM-YY

Example: 09-19 = September 2019

Recertification: Required at 12 years, then every 5-10 years

Large Stationary Tanks (120-1000 gallons)

Tank Type: ASME

Date Location: Metal nameplate attached to tank

Format: Full date written out or MM-YY

Example: "MANUFACTURED: JUNE 2020" or "06-20"

Recertification: Not required for ASME tanks; regular inspection required

Exchange Tanks (Blue Rhino, AmeriGas)

Date Handling: Exchange companies manage dates for you

What to Know:

Exchange tanks are always within certification

Company recertifies or replaces tanks as needed

You don't need to check dates on exchange tanks

Dates still stamped on collar for verification

Part 8: Recertification Process

How to Get a Tank Recertified

Step 1: Find a Certified Facility

Propane suppliers

Welding supply stores

Fire extinguisher service companies

Some hardware stores

Search "propane tank recertification near me"

Step 2: Bring Tank for Inspection

Tank must be empty or nearly empty

Professional will inspect tank

Will check for damage, corrosion, age

Step 3: Testing Performed

External Visual Inspection (E):

Visual check of tank exterior

Check for dents, rust, damage

Takes 5-15 minutes

Cost: $15-30

Valid for 5 years

Proof Test (S):

Pressure test of tank

More thorough than visual

Takes 30-60 minutes

Cost: $25-50

Valid for 7 years

Volumetric Expansion Test (V):

Most comprehensive test

Water-filled and pressurized

Measures tank expansion

Takes 1-2 hours

Cost: $40-75

Valid for 10 years

Step 4: New Date Stamp Applied

If tank passes inspection

New stamp applied to collar

Includes date and inspection type (E, S, V)

Step 5: Tank Returned to Service

Tank is now certified

Safe for another certification period

When to Replace vs. Recertify

Recertify If:

✅ Tank is 12-25 years old

✅ No significant damage

✅ Minor surface rust only

✅ Valve is functional

✅ No safety concerns

✅ Recertification cost < new tank cost

Replace If:

❌ Tank is 25+ years old

❌ Significant damage or corrosion

❌ Valve damaged or needs replacement

❌ Unknown history or missing date

❌ Recertification cost > new tank cost

❌ Safety concerns identified

Part 9: Frequently Asked Questions

Q1: How do I find the date on my propane tank?

A: Look at the metal collar on top of the tank (for portable cylinders) or the metal data plate (for large stationary tanks). The date is stamped as numbers in MM-YY or YY-MM format. Example: 06-21 means June 2021.

Q2: What does the date on a propane tank mean?

A: The date indicates when the tank was manufactured (birth date). This tells you the tank's age and when it needs recertification. Most portable tanks need recertification 12 years after manufacture date.

Q3: How do I know if my propane tank is expired?

A: Check the manufacture date on the collar:

Calculate tank age (current year - manufacture year)

If tank is 12+ years old and has no recertification stamp → Expired

If tank has recertification stamp, check that date + 5-10 years (depending on test type)

If tank is 25+ years old → Should be replaced

Expired tanks cannot be legally refilled or used.

Q4: Can I use a propane tank without a visible date?

A: No. If the date cannot be determined, the tank should not be used. Propane refill stations will refuse tanks without visible date stamps. The date is essential for:

Verifying tank age

Determining recertification status

Ensuring safety compliance

Replace tanks with illegible or missing date stamps.

Q5: How long is a propane tank good for?

A: Depends on tank type and maintenance:

Maximum safe life: 25-30 years for most portable tanks

Q6: What happens if I use an expired propane tank?

A: Risks include:

⚠️ Illegal - Against fire codes and regulations

⚠️ Refusal - Refill stations won't fill expired tanks

⚠️ Insurance Issues - Insurance may not cover incidents

⚠️ Safety Risk - Old tanks may have undetected damage

⚠️ Liability - You're responsible for any incidents

Always use tanks within their certification period.

Q7: Do propane exchange tanks expire?

A: Yes, but exchange companies manage this for you. Companies like Blue Rhino and AmeriGas:

Track tank dates

Recertify or replace tanks as needed

Ensure all exchange tanks are within certification

You don't need to check dates on exchange tanks - the company handles it.

Q8: How much does propane tank recertification cost?

A: Cost varies by test type:

Compare to: New 20 lb tank costs $30-50 (empty) or $15-25 (exchange, full)

Q9: Can I recertify a propane tank myself?

A: No. Recertification must be performed by:

DOT-certified facilities

Licensed professionals

Trained technicians with proper equipment

DIY recertification is illegal and unsafe. Only professionals can apply recertification stamps.

Q10: Where can I get my propane tank recertified?

A: Find certified facilities at:

Propane suppliers (local companies)

Welding supply stores

Fire extinguisher service companies

Some hardware stores

RV service centers

Search: "propane tank recertification near me" or call local propane suppliers.

Conclusion: Understanding Dates Keeps You Safe

Reading the date on a propane tank is simple once you know where to look and how to interpret the code. This knowledge is essential for safety, legal compliance, and proper tank maintenance.

Key Takeaways:

Dates are stamped on the collar (portable tanks) or data plate (large tanks)

Format is usually MM-YY (06-21 = June 2021) or YY-MM

Manufacture date is the starting point - Tank needs first recertification at 12 years

Recertification stamps have letters - E (visual, 5 years), S (proof, 7 years), V (volumetric, 10 years)

Portable tanks expire at 12 years without recertification, or after 5-10 years from last recertification

Maximum safe life is 25-30 years - Replace older tanks

Exchange tanks are always certified - Companies manage dates for you

Recertification costs $15-75 - Compare to new tank cost ($30-50)

Cannot recertify yourself - Must use certified professional

Missing dates = unsafe tank - Replace tanks with illegible or missing dates

By understanding how to read propane tank dates, you can ensure your tanks are safe, legal, and properly maintained throughout their service life.

Last Updated: July 2026

Complete Guide: How Do You Read the Date on a Propane Tank?

Disclaimer: This guide is for informational purposes. Propane tank regulations may vary by jurisdiction. Always consult local codes and certified professionals for specific requirements. If you have any doubt about a tank's safety, do not use it-have it inspected by a professional.