How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactured and modular homes
How do I tell the age of a GSW water heater from the serial number?
Monday, March 2, 2020
The first two numbers in the serial number are the year of manufacture, and the third and fourth numbers are the month for GSW water heaters. There may, or may not be, an initial letter before the numbers. For example, a serial number U1310372185 means that the water heater was manufactured in October of 2013.
To determine the age of another manufacturer/brand of water heater, go to How do I determine the age of my water heater?
• • • • • • • • • • • • • • • • • • • • • • • • • • • •
Here’s links to a collection of more blog posts about WATER HEATERS:
• Are water heaters required to be raised off the floor?
• Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?
• Where are gas water heaters not allowed to be installed?
• Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code?
• Can you use a light switch for a water heater disconnect?
• How can I tell if a water heater is HUD-approved for mobile/manufactured homes?
• Can you wire a 240-volt water heater with 120 volts?
• Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?
• What is the minimum clearance to doors and windows for an outdoor tankless gas water heater?
• What is required clearance for access and working space in front of an electric water heater?
• Why is the water heater older than the house?
• Does a water heater need a shut-off valve?
• Why should a tankless water heater have an isolator/service valve kit installed?
• When was a gas water heater first required to be elevated 18 inches above a garage floor?
• Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home?
• What is the purpose of a thermostatic mixing valve above a water heater?
• Does a tankless gas water heater still work with no electricity during a power outage?
• Why do water heaters have a sacrificial anode?
• What is the difference between a manufactured/mobile home water heater and a regular water heater?
• Does a tankless water heater require a pressure relief valve?
• When is a water heater drain pan required?
• Why is there water in my water heater drain pan?
• What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"?
• Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom?
• Where do I find the water heater in a mobile home?
• Does a tankless water heater in an attic require a drain pan?
• Does an electric water heater require a disconnect?
• Is a catch pan and drain piping required for a replacement water heater?
• What is the difference between a single element and dual element electric water heater?
• What is an FVIR water heater?
• What's that powdery crust on the pipe connections at the water heater?
• What are the most common installation mistakes with water heater replacement?
• Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises?
• What can I do to make my water heater last longer?
• How can I determine the age of a water heater if the serial number is missing or decoding it is impossible?
• How does a hydronic heating system work?
• What is the difference between a regular water heater and a direct vent water heater?
• What is the difference between a regular water heater and a power vent water heater?
• What is backdrafting at a gas water heater?
• How do I determine if a water heater is gas or electric?
• What does it mean when a gas appliance (water heater, furnace, or range) has been "red tagged"?
• What's the valve with the flip-up handle on the water heater for?
• Why is an older water heater an insurance problem?
Visit our WATER HEATERS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.
of Blog Posts
Top 5 results given instantly.
Click on magnifying glass
for all search results.
Buying a home in North/Central Florida? Check our price for a team inspection by two FL-licensed contractors and inspectors. Over 8,500 inspections completed in 20+ years. In a hurry? We will get it done for you.