InterNACHI Water Heater Dating Chart

Use this chart to determine the age of a water heater tank.
Manufacturer

Trade Names

Where to Look

How to Decode

Example

AmericanACE,American, American Hardware, America’s Best, Apex, Aqua Temp, AquaTherm, Aquamatic, Best, Best Deluxe, Champion, Craftmaster, De-Limer, Deluxe, Eagle,The Earl’s Energy Conservation Water Heater, The Earl’s Energy Saver Plus, Envirotemp, Four Most, Hotmaster, Hotstream, King-Kleen, King-Line, Master Plumber, Nationaline, Neptune, Penquin, Premier Plus, Premier Plus Self Cleaning Prestige, ProLine and ProLine Plus, Quaker, Quick-Flo, Raywall, Revere, Riveria, Sands, Sentinal, Servi-Star, Shamrock, Special Deluxe, Standard,Super Eagle, Super-Flo, Supreme, Sure-Fire, Thoro-Clean, Tru-Test, Tru Value,U.S. Supply, Whirlpool, XCL Energy SaverSerial# – 1st 4 digits1st 2 digits = year

2nd2 digits= week

8906xxx= made in the 6th week of the year 1989
Apollo Comfort ProductsApollo
Bradford-WhiteBradfordWhite, JetGlasSerial# – 1st 2 letters
1st letter = year starting with A as 1984.  This letter is on a 20-year loop.
A=1984 or 2004
B=1985 or 2005
C=1986 or 2006
D=1987 or 2007
E=1988 or 2008
F=1989 or 2009
G=1990 or 2010
H=1991 or 2011
J=1992 or 2012
K=1993
L=1994
M=1995
N=1996
P=1997
S=1998
T=1999
W=2000
X=2001
Y=2002
Z=2003
2ndletter = month with January (A) through December (M)
JMxxx= made in the year 1992 (J) in the month of December (M)
A=January
B=February
C=March
D=April
E=May
F=June
G=July
H=August
J=September
K=October
L=November
M=December
CrispaireE-tech
Giant Factories
Giant
Date on tank label
GSW Water HeatingJohnWood, GSW, Moffat, Superflue, MedalSerial# – 1st 4 digits1st & 2ndnumber = year,

3rd& 4th number = month

8901xxx= made in the year 1989 in the first month, January
Heat Transfer ProductsHeatTransfer
LochinvarEnergySaver, Golden Knight, Knight
MarathonMarathonSerial# – 1st 4 digits1st & 2nddigit = month,

3rd& 4th digit = year

0189xxx= made in the year 1989 in the first month, January
MaytagMaytag

 

Manufacturer

Trade Names

Where to Look

How to Decode

Example

RheemAquaTherm, General Electric, Hotpoint, Professional, Rheem, Vanguard, WesternAutoSerial# – 1st 4 digits1st & 2nddigit = month,

3rd& 4th digit = year

0189xxx= made in the year 1989 in the first month, January
RichmondRichmondSerial# – 1st 4 digits1st & 2nddigit = month,

3rd& 4th digit = year

0189xxx= made in the year 1989 in the first month, January
RuudProfessional,RuudSerial# – 1st 4 digits1st & 2nddigit = month,

3rd& 4th digit = year

0189xxx= made in the year 1989 in the first month, January
Sears, Roebuck and Co.Kenmore
A.O.Smith Water ProductsNational,A.O. Smith, Glascote, Perma-GlasSerial# – 2nd, 3rd, 4thcharacters2ndposition(letter) = month (A being January through M being December)

3rd& 4th position (numbers) = year

AJ89xxx=  made in October (J) of 1989
State IndustriesStateSerial# – 1st 3 charactersfirst letter = month (A being January through M, being December), 2ndand 3rdposition (numbers) = yearJ89xxx= made in October of 1989
Summit Manufacturing

Mortex

SunTherm

 

Manufacturer

Trade Names

Where to Look

How to Decode

Example

U.S. Craftsmaster

Water Heaters

Ace,American Hardware, America’s Best, Apex, Aqua Temp, Aqua Therm, Aquamatic,Best, Best Deluxe, Craftmaster, De-Limer, Deluxe, Eagle, The Earl’s EnergyConservation Water Heater, The Earl’s Energy Saver Plus, Envirotemp, FourMost, Hotmaster, Hotstream, King-Kleen, King-Line, Master Plumber, Nationaline, Neptune, Penquin, Prestige, Pro-Line, Pro-Line Plus, Quaker,Quick-Flo, Raywall, Revere, Riviera, Sands, Sentinal, Servistar, Shamrock,Special Deluxe, Standard, Supereagle, Super-Flo, Supreme, Sure-Fire, Thoro-Clean, True-Test, Tru Value, U.S. Craftmaster, U.S. Supply, Whirlpool,XCL Energy SaverSerial# – 1st 4 digits1st 2 digits = year

2nd2 digits= week

8924xxx= made in the 24th week of the year 1989
Vaugn Manufacturing Corp.Sepco, Hydrohot, D.W. Whitehead
hot-water-tank-pic
How to Inspect Water Heater Tanks” online video course at NACHI.TV.  Free to InterNACHI members.