hot water Archives - Charles Buell Consulting LLC

November 1, 2014 by Charles Buell

How can your water heater be too hot and not hot enough all at the same time?

Having plenty of hot water is not just a convenience, it is considered a necessity in modern homes.

However, there are competing concerns related to having plenty of hot water. On the one hand we want to prevent scalding. On the other hand it is a good idea to keep water hot enough to prevent water-borne bacteria from flourishing. It is actually quite complicated to accomplish both goals with storage-tank type water heaters. This is further complicated by Washington State Home Inspector Standards of practice that require us to report when the tested water temperature is above 120 degrees Fahrenheit (including a statement that the generally accepted safe temperature is 120 degrees Fahrenheit).

This information however only address one of the safety concerns–and can actually make the other concern worse. Temperature below 120 degrees Fahrenheit is considered ideal for the growth of harmful bacteria inside the tank–such as Legionella. Keeping the tank temperature between 135 and 140 degrees Fahrenheit can greatly reduce the risk of growing bacteria in the tank but is not a guarantee. For example, Legionella Bacteria can survive extreme hot water and chemical treatment by forming a parasitic relationship with amoebae that are not affected by these treatments. While rare, it is still considered prudent, given the current state of knowledge, to maintain the tank water temperature between 135 and 140 degrees Fahrenheit to at least provide some degree of protection.

Electric water heaters are considered to represent the highest risk, while gas fired water heaters represent the lowest risk. Resolving this difficult issue is perhaps the strongest argument one can make for on-demand type water heaters that do not have this issue as no stored water is present. Homes with copper type pipes are also at lower risk while areas with hard water are considered at greater risk. Non-chlorinated water supply systems are at higher risk (wells).

While “generally-healthy-people” are fairly resistant to infection, some patient populations (organ transplants, diabetes, cancers, kidney disease etc), immunocompromised persons, heavy smokers, heavy drinkers, the elderly and infants can be expected to have higher death rates or incidence of more severe illness if the bacteria is present in sufficient numbers. Some authorities assert that an increase in incidence can be expected with an increased focus on conserving energy (lowering the thermostat on the water heater). The science around all of this is ongoing and new information should be anticipated.

But what about scalding? Preventing scalding requires a multifaceted approach. #1. We must resort to common sense: • Never leave a child or the infirm alone while drawing water in a bathtub, and check the water temperature before putting your child or the infirm in the tub. • Test the water temperature before bathing or showering. • Turn the cold water on first, then add hot water until the temperature is comfortable. • Teach children to turn the cold water on first, and the hot water off first. #2. Provide a mechanical means (Thermostatic mixing valve) of lowering the temperature to below 120 degrees Fahrenheit at either the points of use or at the water heater itself to protect the whole house. Because these devices can fail, we must always keep #1 in mind.

For additional information on this issue please check out the links below:
http://EPA/Legionella: Drinking Water Fact Sheet
http://EPA/Legionella: Drinking Water Health Advisory
https://OSHA/Domestic Hot Water Systems
http://Wikipedia/Legionella
http://Wikipedia/Legionnaires’ Disease

Charles Buell, Real Estate Inspections in Seattle

August 24, 2014 by Charles Buell

How hot is the water at your tub/shower?

Modern construction regulations require that some means of limiting water temperatures of the hot water being delivered to tubs, showers and bidets be installed. This is achieved by installing pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve at the fixtures themselves.

On a recent inspection I was not surprised to find the water temperature at the bathroom sink to be 147 degrees Fahrenheit.

It is very common to find water temperatures in homes set way too high. 147 degrees will cause 2^nd and 3^rd degree burns in under 2 seconds. You could not put your baby (or granny) in the bath and out of the bath in 2 seconds. The baby might not even start screaming in that short of time (and granny might just have a heart attack)–resulting in the baby being in there even longer.

What did surprise me about the water temperature was that it was the same temperature at the tub. The following picture of my thermometer shows the water temperature–132 degrees Fahrenheit which is way too hot and it eventually got all the way up to 147 degrees Fahrenheit.

This could lead one to think that perhaps the wrong valve was installed–or that the correct valve was installed but was not adjusted properly.

In new construction there should just plain never be water this high at the tub fill.

Of course the same is true of any age construction but in new construction it is something that needs to be “fixed” as opposed to being “upgraded.”

Some homes have tempering valves that limit the water temperature from the source of the hot water (water heater), but this type of in-line tempering valve is not meant as a replacement for limiting high temperatures at the points of use. This tempering valve is adjustable—and should be set at under 120 degrees Fahrenheit. The valve functions by mixing a little cold water into the hot water. These valves are a great way to give a layer of protection to older homes that do not have fixtures at the points of use that can limit high water temperatures.

Current regulations require that water delivered to tubs and showers be no greater than 120 degrees Fahrenheit and that water delivered to bidets be no more than 110 degrees Fahrenheit. It is the homeowner’s responsibility to make sure that hot water temperatures are safe–and they should be checked periodically–and have them adjusted accordingly.

It can be very difficult in the context of a home inspection to determine or verify proper water temperatures. Temperatures certainly will not be verified at every location. Water temperature should be taken at the beginning of the inspection and at the end of the inspection at a minimum, because a huge percentage of the time the tested temperature at the beginning of the inspection will be much lower than the end of the inspection after the water heater has fired and brought the whole tank up to the highest temperature. This scenario is especially true of unoccupied homes.

Do you know what your water temperature is?

By Charles Buell, Real Estate Inspections in Seattle

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January 8, 2011 by Charles Buell

How Hot is the Water at Your Faucets?

When I was a kid I can remember water being boiled on the wood cook stove in the Kitchen to make the hot water we would expect to get from a hot water heater today.

We do everything in our power today to have all the hot water we could ever want—-whenever we want—wherever we want. We must still be careful to not let the water get TOO hot.

Human skin is comfortable in a relatively narrow range of temperatures without being damaged. Normal skin temperature is usually around 91 degrees. According to the CPSC (Consumer Products Safety Commission) there are more than 3800 scalding injuries and 34 deaths per year from tap water that is set too high. Most of these injuries involve children under five and the elderly.

Washington State Home Inspectors are required by our Standards of Practice to state in the written report whether we tested the water temperature or not and to state that the recommended water temperature should not exceed 120 degrees Fahrenheit.

Make sure your water temperature is not set higher than 120 degrees Fahrenheit. If you don’t have enough hot water at that temperature, you either need more supply (bigger tank) or some sort of temperature regulator (tempering valve) on the system so that the tank temperature can be set higher while delivering 120 degree water where you need it.

There are some advantages to keeping the water in the tank above 130 degrees Fahrenheit to prevent the growth of some types of bacteria—including Legionella—making a tempering valve a wise choice. This also creates a greater supply of hot water by having a higher temperature of water to dilute down to 120 degrees.

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