Electric water heater hot water running out while showering

It sounds like the lower heating element is not working. I would suspect either the element, or a thermostat. Are you sure the BOTH thermostats are wired properly? The upper one feeds the lower one once it has reached its set point.

It's also possible that sediment has built up in the tank and is covering the lower element.
You could try draining the tank to see - make sure the power is off, because the elements will quickly burn out if not submerged.

It might make more sense to replace the tank if it's more than a few years old.

Interesting thought about sediment build up. If that's the case should a filter be installed prior to the water heater to prevent further build up?

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I am on a well, and use a 5 micron whole house filter. Since installing the filter some years ago, I no longer get bits of sand in the toilet tanks, and who knows where else it went - like washing machine valves, dishwasher valves, etc. I do get a bit of sand trapped in the filter. I don't have a hot water tank, but I don't need crud jamming faucets and valves. Depending on what's in your water, a filter would be a good idea and could prevent problems.

IIRC, most water heater manufacturers recommend a periodic draining of the tanks to remove sediment, as well as a periodic replacement of the sacrificial anode (cathode?). But how many people do that?

Since you are on a well, save yourself a lot of time and just buy a new unit. the $200-300 you spend will save you hours of screwing around and give you a warranty. Where I used to live the water was so hard you could only get a year out of the elements and after about 3 years you could not even chip the sediments out of the bottom.

Hang in there OP. You can fix this.
If you have hard water the sediment collecting in the tank is actually the minerals "falling" out of the water when its heated. No amount of filtering will remove those minerals or prevent the sedimentation. The water heater is basically acting as a water softener since its removing the minerals.

There's absolutely no reason to replace an electrical resistance type water heater unless the tank is leaking or you can't service it. In my case, I couldn't remove one of the elements so I had to replace one of our two 30 year old units. The remaining 30 year old unit gets yearly cleanings and an occasional heating element change. As someone said, the sediment (precipitants actually) will build up and engulf the lower element causing it to break. I have to remove the element and drain valve an then remove the minerals manually. Not too long ago I installed a drain valve that allows me to insert an auger-style drill bit that I turn with a cordless drill to break up the minerals so they will flush out. They won't flush out otherwise.

I second the sediment buildup as a cause for your problem.
A broken or missing dip tube may also be the cause of your problem. It inserts from the top on the water inlet. You can see if its intact when you remove an element.

http://www.waterheaterrescue.com/ is a great reference site.

semipro said:

A broken or missing dip tube may also be the cause of your problem. It inserts from the top on the water inlet. You can see if its intact when you remove an element.

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The dip tube brings new cold water to bottom of tank. If tube is broken, the cold water entering the top of tank mixes immediately with the hot water at top of tank.
A broken dip tube was the problem on my old gas DWH. Suddenly started noticing only a 5 minute hot showers. It was a quick fix, and the tank lasted a couple more years.

if you are truly in boston and not a suburb you have mwra water it's not hard water but you can still get buildup like semipro said. you will need more than a multimeter you will need a amp probe. i get these calls all the time. run your water til you have cold coming out of the tap then grab a chair and sit by your tank while the top element is working you should notice a slight hiss coming from your tank. then after 10 to 20 minutes go by depending on the size of your tank you will hear the hiss stop that is when the thermostat switches to the lower element you should hear the same hiss. if you start hearing bubbles or crackling coming from your tank then you got buildup. if you hear nothing it might be time for a new element on the bottom. if you can get a amp probe it's much easier. put the amp probe on one of the wires going to the top element that reading should be around 18 amps give or take a amp and if it is a 4500 watt element. when that element is done heating put the amp probe on one of the wires going to the bottom element and you should be getting the same as the top if nothing and there is 240 volts at the screws on the element there is your problem. i think it is a 1.5 inch deep socket

Maintaining tank water heaters is not cost effective. They’re very cheap. Just pop a new one in when something like this happens.

yep that what i usually say to the customer. especially if there is the slightest little rust on the threads of the element. it might not come out and if forced out they leak again and sometimes do not seal at all

This is how I see repair versus replace costs working out for me.
I used the price of a new low-end electric WH from Lowes and an hourly labor rate of $45/hr which is very conservative.
I've been maintaining our unit under this way for almost 20 years now. It was over 10 years old when we moved in.
We have hard water BTW and the heating elements are about $15. As long as you maintain a good sacrificial anode, a good-quality glass lined tank is unlikely to leak.



Added benefits of repair versus replace:

• less stuff going to the landfill. Even if you break down a WH to recycle the metals there's lots of insulation to dispose.
• less mileage costs (fuel, wear and tear)
• less embedded energy and material life cycle costs e.i., WH production and recycling versus that of the repair parts
• less investment of my limited time

CincyBurner said:

The dip tube brings new cold water to bottom of tank. If tube is broken, the cold water entering the top of tank mixes immediately with the hot water at top of tank.
A broken dip tube was the problem on my old gas DWH. Suddenly started noticing only a 5 minute hot showers. It was a quick fix, and the tank lasted a couple more years.

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This^

A non- functional bottom element will still give you about half a tank of hot water tapering off in temperature slowly. A broken dip tube will only give a couple gallons of hot with a rather quick transition to cold.

Some water heaters have 3/4" inlets. Use a copper 3/4 npt x 1/2 sweat fitting. Ream out the ring that stops the 1/2" copper pipe. Loosely install the fitting and slide a lenght of 1/2" copper through it till contact with the bottom of the tank. Lift up about 2 inches and mark the pipe. Unscrew the fitting and lift the assembly up enough to sweat the pipe to the fitting. Then use a fitting of your choice to connect the 1/2" copper to your water line.

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It's one of the elements. I think mine was $15. Use an ohm meter across the element terminals. Mine needed a special element socket to get it out.

I am a plumber of over 30 years experience, I have seen this before. replacing the dip tube is your next logical step. As a previous post stated. It's a simple repair and a flexible dip tube is available if you don't have overhead clearance..

using a ohm meter doesn't always work. at a low temp the element will read fine when you apply electricity it heats then opens up and depending on the minerals in the water will determine if it blows the breaker or fuse or it runs low enough to not make hot water, if you checking a element amp probe is the way to go. if you have a amp probe this is the easiest thing to do before taring it apart.

semipro said:

This is how I see repair versus replace costs working out for me.
I used the price of a new low-end electric WH from Lowes and an hourly labor rate of $45/hr which is very conservative.
I've been maintaining our unit under this way for almost 20 years now. It was over 10 years old when we moved in.
We have hard water BTW and the heating elements are about $15. As long as you maintain a good sacrificial anode, a good-quality glass lined tank is unlikely to leak.

View attachment 221882

Added benefits of repair versus replace:

• less stuff going to the landfill. Even if you break down a WH to recycle the metals there's lots of insulation to dispose.
• less mileage costs (fuel, wear and tear)
• less embedded energy and material life cycle costs e.i., WH production and recycling versus that of the repair parts
• less investment of my limited time

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Ha! You don’t replace it until it stops working right. Then just pop a new one in. Might be 20 years or more. Also keep in mind that average home ownership is 7 years so ...

I've done it both ways in my many years of home ownership. What I've come to learn (at least for me) is that if you are starting to have open elements, used-up anodes, encrusted sediment, etc, it's just an indication of more trouble to come. Other than maybe a simple element replacement, I think it's usually most cost effective and trouble effective to replace the tank. Darn near as easy as any other repair. Just my take.

Of course, if you're having recurring problems with a relatively new heater, you would certainly want to determine why.

in the next town over from here water is so harsh that a plumber i know has a few customers that every 2 to 3 years the tank rots out. i guess it all depends on your water. where i used to live the water was great it was a normal thing for water tanks to last 15 to 20 years

fbelec said:

in the next town over from here water is so harsh that a plumber i know has a few customers that every 2 to 3 years the tank rots out. i guess it all depends on your water. where i used to live the water was great it was a normal thing for water tanks to last 15 to 20 years

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I'm no expert but I wonder if it's an iron problem. I've seen areas that have so much iron that it causes awful problems. Sometimes you just need a heavy-duty water softening system that also takes out iron. But it's expensive. But yes, hard water quality can really do in a lot of appliances.

Whenever we've looked for property to buy, water is nearly the first thing I look at.

Under good conditions, a 50 gallon tank should last 15-20 years. But not all conditions are good for sure.

Make sure that there is water, and plenty of it when looking at properties. It’s easy to repair just about any problem the water may have. Relatively cheap too. PH, hardness, iron, all can and should be dealt with for the health of you and your home.

Sprinter said:

I'm no expert but I wonder if it's an iron problem. I've seen areas that have so much iron that it causes awful problems. Sometimes you just need a heavy-duty water softening system that also takes out iron. But it's expensive. But yes, hard water quality can really do in a lot of appliances.

Whenever we've looked for property to buy, water is nearly the first thing I look at.

Under good conditions, a 50 gallon tank should last 15-20 years. But not all conditions are good for sure.

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yes iron. we have such a high iron content in the water that people running a well for sprinkler systems usually have a rust ring around the biz or house about 4 foot tall

fbelec said:

yes iron. we have such a high iron content in the water that people running a well for sprinkler systems usually have a rust ring around the biz or house about 4 foot tall

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Yeah, I've seen terrible rust problems even in the same county (or less area) as good water areas. I guess a geologist friend of mine could explain it nicely. It is a treatable condition, if expensive, and that depends on whether it's ferric or ferrous iron and other factors. You can treat for it for residential use, but what do you do for high volume irrigation systems? I don't know. It can be a real problem for many and something to try to avoid (if possible) and treat (if practical).

Sprinter said:

Yeah, I've seen terrible rust problems even in the same county (or less area) as good water areas. I guess a geologist friend of mine could explain it nicely. It is a treatable condition, if expensive, and that depends on whether it's ferric or ferrous iron and other factors. You can treat for it for residential use, but what do you do for high volume irrigation systems? I don't know. It can be a real problem for many and something to try to avoid (if possible) and treat (if practical).

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Iron is super easy to deal with. You size the iron treatment system for the flow rate so bigger flows just mean bigger treatment. The last one I put in was for 1050 gpm. The treatment vessel was the size of a large van.

Highbeam said:

Iron is super easy to deal with. You size the iron treatment system for the flow rate so bigger flows just mean bigger treatment. The last one I put in was for 1050 gpm. The treatment vessel was the size of a large van.

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Hah, I was hoping to hear from you on this. I figured you would have an insight. My only experience has been looking at properties that have often seemed hopeless. I remember one that had a household treatment system that didn't seem to be doing squat. The whole place was brown from it. I'm no CE but I know what I don't like to see

Oh, I gotta brag about my nephew. Just got an MS in CE and his PE. But he's into bridges and stuff.