Water heater capacity

Is there a code that states what the minimum capacity of a water heater should be in a 4 full bathroom home. This home has a 50 gallon capacity NG water heater. I have looked in the code book but can’t find a thing. I have seen a chart saying it should be 66-75 gal. capacity. Does anyone have any info on this.

There is no code that even requires a water heater at all. It only says means shall be provided to heat water. That could be a pot on the range.


Bradford White has a Residential sizing Guide.

Type in the Info and you receive three options…

I have been using this for many years to the Satisfaction of many Home Buyers…


Try using the reference below.

water htr cap03.pdf (9.49 KB)

These 2 100 gal electric HW tanks with the nice copper plumbing supply 29 units in a condo, that’s less than 5 gal/bath. Mind you these are Canadian gallons.:smiley:

Grossly Inadequate.

What is the Question?

Could one not employ those two 100 gal tanks with a mixing valve such that the tanks produce extremely hot water, then water it down some with cold… thus stretching it… perhaps by double? Suppose they have a half-decent recovery time and it all might work out ok… no?

I’ve seen individual units in a multifamily piped in sections to smaller water heaters and then the typical central hi capacity heaters. A lot of time it depends on who is paying for electric or gas. I’m not sure you could sell a new house without a WH, although you could call it energy efficient.
Brians pdf is a pretty good rule of thumb, but it could depend on the buyer too.

The building manager says there’s always plenty of hot water for everybody. I wasn’t questioning this, the building has been occupied for 25 years. That chart is based on a temp setting of only 100 degrees F, by the way. I’m sure these tanks are set to run hotter.