Running out of hot water too soon

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Flyover

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Before we bought this house 3 years ago it was a rental for a number of years, and there's lots of evidence that the owners were the types of landlords who don't do any maintenance except for emergencies.

So even though the water heater is only about 6-8 years old (they replaced it when the previous one blew up) and it's the same size as every other water heater we've had in our previous homes, we've noticed that lately we'll run out of hot water much earlier than we used to.

My uneducated guess is that this is due to scale buildup in the water heater, from years of non-maintenance. So, two questions:

1. How can I find out if I'm right?
2. I only know about preventative maintenance on water heaters. Is there a way to remove scale once it's already built up?
 

bud16415

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Is it gas or electric?


There isn’t too much you can do once it starts going. Once you drain it you will get some clues by what comes out if you can even get water out the drain. I just replaced the gas fired water heater that was in this house when we bought it 6 years ago. I was going to replace it then but lit it and it made hot water so I let it go. I had to tip it over and drain it out the top and it still weighed a ton.


One thing I do now is take a sharpie and put the date on stuff when I replace it.


Its not a bad DIY job just get a strong helper to get it in place. With my PEX setup once I had it in the basement it was a 15 minute switch over.


Don’t do what I did and wait for it to start leaking before you get a new one.
 

Flyover

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It's gas.

Shortly after we moved in I tried to drain/flush it just like I had done with the one at my previous house, but nothing came out; I think it really was just that clogged. It still heated up water so I gave up draining/flushing it after that -- same as you, @bud16415.

Because of how they installed it (also maybe how they built the house) it's basically impossible to move, even just to tip. It's sorta jammed in a closet off the garage, along with the furnace, and the piping and ducts would have to not just be disconnected but completely removed to make a path for removing or even just tipping the water heater.
 

bud16415

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If it is still making hot water I would wait till spring when it will be warmer working on it in the garage. Maybe make some plans to improve the area it is located in at the same time. I have seen them crammed in like that before it is almost like the equipment was an afterthought.
 

pjones

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Is it possible the temperature setting just got bumped to a lower setting than it previously was set at? Some people turn it the temperature down for safety. A cooler tank doesn’t go as far and will appear to run out of water quickly.

If you have a thermometer you can check and see if it is providing 140deg F.
 

Jeff Handy

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140 degrees is pretty hot, too easy to get scalded, unless you have a tempering valve system that adds in cold water to the hot flow.

Although you might mean 140 thermostat settings for the elements, which I guess would not be putting out 140 water all the time.

I only have limited experience with electric water heaters, so ignore me if I am way off.
 
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pjones

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140 degrees is pretty hot, too easy to get scalded, unless you have a tempering valve system that adds in cold water to the hot flow.

Although you might mean 140 thermostat settings for the elements, which I guess would not be putting out 140 water all the time.

I only have limited experience with electric water heaters, so ignore me if I am way off.
It must be different for different building codes. In Canada it is recommended to have it set no less than 130 degF to prevent the formation of dangerous bacteria. The tanks come preset at the recommended temperature of 140 degF. At 140 Deg it can cause a scaled burn in 6 seconds for an adult so people often turn it down when they have kids or elderly living in the house for safety reasons. A dishwasher should have 140 Deg supply so it can clean properly (160deg in a commercial kitchen).

Most all our taps in my area mix the supplied hot and cold water as you turn them on (not two separate faucets like in other areas). You could install a mixing valve at each tap for safety as an alternative.
 

bud16415

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I also run ours hot 140-150, but we are two adults and we know what we have and use it accordingly.


I have an outside hot tub and find the pure hot setting works great for adding water without chilling the tub and I also use it for ice removal on the deck and cover. It is gone really quick with a needle jet nozzle and good hot water. The dishwasher as mentioned above is another and having a hotter supply just gives the tank in effect more volume.


If we had little kids I would back it down.
 

68bucks

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You say you noticed lately that you're running out of hot water, was it better not that long ago? If so you may have a broken dip tube.
 

Flyover

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@68bucks: Yes, it was better not that long ago. What is a dip tube and how can I find it and tell if it's broken?
 

68bucks

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Hot water tanks have a tube, usually plastic, that inserts into the tank on the inlet side that directs the cold water to the bottom of the tank. The hot water stays on top and is pushed out by the incoming cold water. When a tube breaks off, say half way down, the cold water only goes in half way down so the cooler mix of hot and cold comes out before the hot water is fully exhausted. The only way to fully confirm that is to pull the tube. I would buy a new tube if you plan to pull it out so you only have to tear it apart once. They aren't very expensive. I would also rule out a bad element first since you can do that much easier. I bet there are lots of YouTube videos that show how to pull a tube.
 

Flyover

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Since it's a gas boiler and I am getting hot water (it just runs out quicker than it used to), can I rule out the bad element?
 

billshack

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I once had a case like this. I drained the tank and flushed out 40 lbs of debris and
minerals out the bottom of the tank. the minerals were taking up half the space of the water.
Bill
 

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