Water heater question...

If you’re asking at what temperature the WH should be set at, I think it would depend on your area.

In Quebec, it has to be at 140 F minimum at the WH to prevent bacterial growth and a mixing valve at the tub/shower to reduce it to 120 F maximum to prevent scalding as per building code.

While in Ontario, just across the river, it has to be at 140 F minimum at the WH with a mixing valve at the WH to reduce the temperature to 120 F to prevent scalding at fixtures as per building code.

Actually the code inspector will inspect temp to make sure it is not over 120. If there is not hot water they will require it to be turned on for the next time they return

Yes, in Florida you must have a water heater. But it mentions nothing about minimum temperature. Here is my dilemma and I am trying to help a client and I am against the Realtors, the brokers, the sellers and the plumbers…

They have this tankless water heater that is a total POS. It is 1 inch pipe reduced to 1/2 pipe and hardly no water pressure is present when two showers are ran on hot at the same time.

It states that at 4 GPM it will provide water it will only provide 20 degrees above the temperature of the incoming line. Here in Florida the water stays relatively warm but can get down to 70 degrees, so at 4gpm it would only be able to provide 90 degree water, according to manufacture specifications.

How can I PROVE this is wrong?


Huh?..how much water they can produce given an amount of time. What is the definition of HOT water?

My question was simple, to the point and articulate. I understand that its over your head. I am dealing with specifics and professionals, so its out of your league. Its ok…

Thanks Marcel and I would totally agree and it makes sense. But I am in an battle and do not want to say…well the guys on the message board said…

Thanks for the information and it sounds spot on, I just cant find it anywhere to support my statement. I thought common sense would prevail, that if water trickles out of the shower when two of them are run at the same time, and the water was only temperate at best, then it would be a no brainer…

Guess I was wrong…:smiley:


Russ, maybe this will help. American Society of Sanitary Engineers standards…

Also, manufactures of tempering valves and water heater manufactures will provide you with temperature ranges.

ASSE 1017: Performance Requirements for Temperature Actuated Mixing Valves for Hot Water Distribution Systems
Publication Date: Oct 5, 2009
SDO: ASSE: American Society of Sanitary Engineering
DOD Adopted ANSI Approved Approved

Temperature Actuated Mixing Valves for Hot Water Distribution Systems (herein referred to as “device”) shall consist of a hot water inlet connection, a cold water inlet connection, a mixed water outlet connection, a thermal element and a means for adjusting the mixed water outlet temperature.


Dimensions of pipe threads, flanges and other connections shall conform to appropriate industry standards.

Maximum Working Pressure

The maximum working pressure of the device shall be at least 125.0 psi (861.9 kPa).

Temperature Range

Inlet Water Temperature Range

The hot water inlet temperature range shall be 120.0°F - 180.0°F (48.9°C - 82.2°C) and the cold water inlet temperature range shall be 39.0°F - 80.0°F (3.9°C - 26.7°C).

Outlet Water Temperature Range

The device shall be capable of supplying the domestic hot water distribution system with a minimum adjustable range of 105.0°F- 120.0°F (40.6°C - 48.9°C), provided the hot water supply temperature is at least 20.0°F (11.1°C) greater than the outlet water temperature setting.


Bert it gives me the temperature ranges…they just SUCK. 20 Degrees above the incoming water temp. It gives them to me, I just cant find a code that says its unacceptable.

Here’s one taken from the IPC…

424.3 Individual shower valves. Individual shower and tub-
shower combination valves shall be balanced-pressure, ther-
mostatic or combination balanced-pressure/thermostatic
valves that conform to the requirements of ASSE 1016 or
ASME A112.18.1/CSA B125.1 and shall be installed at the
point of use. Shower and tub-shower combination valves
required by this section shall be equipped with a means to
limit the maximum setting of the valve to 120°F (49°C),
which shall be field adjusted in accordance with the manufac-
turer’s instructions. In-line thermostatic valves shall not be
utilized for compliance with this section.


thanks Bert…you effort is much appreciated, but I found the MAX in the code, its not the max I am worried about, but the minimum…

I truly appreciate your efforts on this, much appreciated brother.

damn, that’s gotta be frustrating, Russ! How about laying it out like you said? The temp will raise 20 degrees warmer than incoming water, of about 70 degrees. 90 degrees temp on your 98 degree body will not feel warm, but the manuf of this POS says its normal…

Russ, hot water, as defined by the FBC, is 110F or above. See http://ecodes.biz/ecodes_support/free_resources/2010Florida/Residential/10FL_Residential.html
Then P2801.1 for the requirements, and go to definition and look at, Hot water.
Hope this helps.


most states or cities have minimum housing standards that a landlord must comply with

i use 120ºF as a baseline unless i’m aware of lesser

let them search for a lesser standard so they can sell their pos

You guys are outstanding. I re read the plumbing code book and no where does it give me a definition of what “hot water” specifically is.

It is very vague and up to the interpretation of the reader.

Sucks, I don’t really have a leg to stand on in writing. Once again, I thought common sense would prevail. I guess not.

I am truly thankful that you took time away from your life’s to assist me, speaks volumes of the organization and its people…

I would approach the question differently.

A water heater is operating correctly when it brings the water to a set temperature.

With a thermostat that has a range of 57 to 160 degrees, a water heater is operating correctly if it brings the water to 57 degrees when it is set to that temperature. When it is set to 160 degrees and can only bring the temperature to 145 degrees, although the water is “hot”, the water heater is not working correctly.

many city tenancy laws require a minimum of 120°F

i say inspect from the eye that the property will be a rental…it may 1 day

Florida Department of Health & their Food Hygiene regs
“Hot Water – means water heated to a minimum temperature of 100 degrees Fahrenheit (°F).”

Sean Harding found it for me…its 110 degrees. It is under definitions for hot water. Thanks Sean for the help and your not even a member…

Agree, but what it it only has a “hot and Hotter” selection and does not give an exact temperature"…

Thanks for the info, very helpful and its always a good thing to look at items from a different perspective, much appreciated.

Advise them to call the county health department for a professional opinion that the others can’t dispute!!!

My guess is that you are right…