Water Heater Sizing

I thought I had seen a chart giving basic rules for correctly sizing a water heater in residential homes. You know 3 bedrooms 2 1/2 bath requires ??? minimum. Anyone know where this can be found.



Bedrooms do not use hot water, people do.

Did you have a bad night or are you usually that sarcastic? There is a code that determines the minimum size of a water heater in a residential home depending on the number of baths and bedrooms.

Ya’ know…on the same lines as septic tank sizing :stuck_out_tongue:



Nothing to fret about.
Brian has keen sense of humor and likes to share it with everyone here.

Pay attention and you’ll “get” him after a while.:slight_smile:

I take it you did not find the charts useful then? :smiley:

Not sure of the code you are referring to?

I’m not fretting. I take it all with a “grain of salt”. After all I work with R/A’s all day…that should count for something…

“fret” was a poor choice of a word Charles. sorry.
Just wanted to let you know that Brian is alright.


A water heater is not expressly required at all by the IRC, and they certainly don’t have any guidelines with regard to sizing. Here’s the code:

*IRC P2801.1 Required. Each dwelling shall have an
approved automatic water heater or other type domestic
water-heating system sufficient to supply hot water to
plumbing fixtures and appliances intended for bathing,
washing or culinary purposes. Storage tanks shall be
constructed of noncorrosive metal or be lined with
noncorrosive material.

In my area, there is a heavy Amish population, who don’t all use water heaters. The code does allow for “other type domestic water-heating system…”, which the inspectors permit to be a pot of water heated on a the stove and delivered via people power to the fixture that it’s going to be used in.

Yes, he is always that sarcastic. I luv Brian for just that reason…:mrgreen:

He wasn’t being smart a

Family Size Tank Capacity (in gallons)
…Electric Gas Oil
1-4/ 50 …30 …30
6 /…65 …40 …30
8+/ .80 …50 …30

This is not a code, just a table that shows which type of heaters have the fastest recovery. It depends on many things. Do you wash clothes in cold water, run the dishwasher once a day or once a week. Cold showers, on and on.

My bedroom uses water. But in order to be earth friendly we get all of the water from the holes in the roof.


the UPC sizes water heaters based on their first hour recovery rating.

here is the chart in PDF format.

Keep in mind this is first hour rating, not tank volumn. a 50 gal tank could have a 54 gal FHR or an 80.