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What do you folks consider "too hot" for water temperature in a building? I have a condo building w/temps >130degF, which I know is WAY too hot and I flagged the temp. as a major scald/burn hazard.

Of course, everyone wants to know what I think is right, so I said 110degF is right, and that 120degF is still a hazard. Anyone got the "official" temp w/a link?

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Originally posted by kurt

What do you folks consider "too hot" for water temperature in a building? I have a condo building w/temps >130degF, which I know is WAY too hot and I flagged the temp. as a major scald/burn hazard.

Of course, everyone wants to know what I think is right, so I said 110degF is right, and that 120degF is still a hazard. Anyone got the "official" temp w/a link?

I thought that 120 degrees was the standard from the manufacturers. Though that isn't hot enough for my own water heater. I happen to like mine set at 130.

No reference, but I've heard that anything below 120 could allow bad bugs to grow in the water.

Also, I've soaked my own personal body in 120-degree hot springs for several minutes at a time and suffered no burns. Of course, I wouldn't want to see a little baby put in 120-degree water. I don't believe it would burn the baby so much as raise her body temperature to a dangerous level.

Edit to add: Here's a link to a US Dept of Energy page: http://www.eere.energy.gov/consumer/you ... opic=13090

- Jim Katen, Oregon

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It's good question, but I don't know exactly how to relate the information to all of these units I'm seeing with no numbers on them. They just start at "Warm" and go to "Very Hot", but they do often have a little factory mark somewhere in between which I assume to be the recommended setting. If they're beyond that I recommend lowering it, or if I simply find the output at sinks, etc. to be just too damn hot. It takes all kinds though. My wife likes it where it would start taking my hide off.

Brian G.

Fond of My Hide, Thank You Very Much [:-bigmout

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When I was an investigator with the Military Police, the standard army policy was that anyting above 125 deg. F. was too hot. The army medical folks told us that a child whose feet were set down in a bathtub with the water at 130 deg. F. would suffer 3rd degree burns within 3 seconds. It was Army policy that residents of government quarters were not to turn their water heaters up over 125 degrees and the sponsor - the soldier who signed for those quarters was held accountable for it - at least officially.

As a Juvenile Investigator in Norddeutschland I investigated four cases over a period of 3 years wherein toddlers were seriously burned by bathtub water. In every case, I ended up apprehending the sponsor, all senior NCO's, and citing them with Disobeying a Lawful Order (Art. 92) for violating that directive and cranking the water heater in their quarters up to above 130 degrees. If you've ever seen a small child seriously burned by a parent's negligence, you'll understand why it used to frustrate me to no end when soldiers allowed this to happen and then their commanders acted like I was the bad guy for apprehending the parent whose negligence had caused those injuries. Every one of them got off with a letter of reprimand and those kids will live their lives with those scars.

Here's a document on the Rheem site that uses those exact temperatures, so I guess the Army medical folks were on the money.



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My report on high or low temperatures:


The water temperature was set at:

I recommend that water heaters be set to 120 degrees. I recommend measuring the temperature, at the faucet closest to the water heater, using a meat thermometer for accuracy. Ensure that enough water is ran, before measuring, to measure the temperature of the water directly from the water heater. Then make necessary adjustments

The following information is from the Consumer Product Safety Commission.

Tap Water Scalding Alert

Each year, approximately 3,800 injuries and 34 deaths occur in the home due to scalding from excessively hot tap water. The majority of these accidents involve the elderly and children under the age of five. The U.S. Consumer Product Safety Commission (CPSC) urges all users to lower their water heaters to 120 degrees Fahrenheit. In addition to preventing accidents, this decrease in temperature will conserve energy and save money.

Most adults will suffer third-degree burns if exposed to 150 degree water for two seconds. Burns will also occur with a six-second exposure to 140 degree water or with a 30 second exposure to 130 degree water. Even if the temperature is 120 degrees, a five minute exposure could result in third-degree burns.

Never take hot water temperature for granted. Always hand-test before using, especially when bathing children and infants. Leaving a child unsupervised in the bathroom, even if only for a second, could cause serious injuries. Your presence at all times is the best defense against accidents and scaldings to infants and young children.

Visit the Consumer Product Safety Commission website at:


For more information.


Hmm,Guess I oughta add something about the dangers of bacteria at low temperatures too.

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  • 1 year later...

I lived in Japan for 12 years and when I took vacations w/ my wives family we often went to hot springs. The water was so damn hot, that by the time I finally got in, everyone else was getting out. I could only stand it for a few minutes and would have a hard time breathing. Neither, could I bath at their house, because they kept the bath water to hot. There was a very very large tub, the water is changed once or so a week and always kept at a constant very hot temperature. Before getting in the bath you would sit on a tiny stool - soap up and rinse off by filling a bucket up under a faucet and poring over your head. After 20 years of marriage, I still cannot get in the shower with my wife, because it is scalding hot to me, and my showers are freezing to her. So while I tell my customers 120 is safe and anything higher could cause scalding and cost more $, I guess a lot of it is what your used to.

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Insert a little advice telling people to install anti-scald valves. It's good advice anyhow, and if your customer does actually install the valve(s) the scalding liability is on the back of the valve manufacturer, not the shallow-pocket HI or plumber.


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From the New Jersey Uniform Construction Code:

5:23-3.15 Plumbing sub-code.

(b) 2 viii The definition of "hot water" shall be deleted and the following definition shall be inserted: Hot Water: Potable water at a temperature of not less than 120 degrees F and not more than 140 degrees F.

(b) 10 vii Section 10.15.1, Hot water supply system, shall be amended to add the phase "Outlet temperature of hot water from lavatory faucets in public facility restrooms (such as those in service stations, airports, train and bus terminals and convention halls) shall be provided with a means to limit the maximum teperature to 110 degrees as required in ASHRAE 90.1-1999".

It doesn't make sense; the second part states "hot water" but the temperature of the second part doesn't meet the definition.



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A while ago (2001-2002), we were doing an addition/remodel in Evanston. Joe Woods a plumbing inspector up there at the time had told me, that 115 max for a bathroom, and 120 for a kitchen.

I did find in the 2003 Illinois Plumbing Code:

Public Lavatories - Max Setting 110 degrees

Shower & Shower bath Combinations - 115 degrees max

Water heaters used for space heating - Must have a Thermostatic Mixing Vavle to prevent temps exceeding 120 degrees.


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