Green hot water!

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  #1  
Old 05-12-19, 06:12 PM
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Green hot water!

OK si I know this may ultimately go under hot water heaters but I figured I'd start here. I've done some reading so I know this is not an uncommon issue, but I was still a bit unclear as to how to best proceed so I thought I'd come here and lay it all out for the experts.

I get a light green hue to the water in a tub when we fill it. only the hot. run the cold only and the water is clear. running the hot till it runs cold and it seems lighter. but then waiting a bit and running the hot again after a full heating cycle and it's greenish again. it is faint enough that it takes a tub full to be evident. you cant really see it in a full sink. Not sure when it started; we just kind of noticed it filling a tub.

I have two hot water heaters, and both are electric. one is 50 gal and the other 40. this is so I have enough to fill the soaking tub. they are run in series with the lines in and out of equal length so that the water is drawn equally from both (I trick I learned here actually). the setup has worked well for about five years now.

all the lines are copper. most no more than five-ten years old. Visually the lines look ok with no evident corrosion.

From what I've read it can be copper from the pipes turning the water green, or perhaps algae growing in the hot water heater(s)?

I read flushing the heaters via the drain at the bottom? Should I test the water to see if it's copper or algae? replace the heaters?

Really just not sure what the simplest/most direct next step is.

I installed the heaters, and did most of the copper work so I'm comfortable with just about anytihng I might need to do.

appreciate the help -- this has become my go-to for diagnoses!

jp
 
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  #2  
Old 05-12-19, 11:06 PM
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There's certainly nothing wrong with flushing the heaters. I know my first question when I started reading was whether you had copper pipes so they certainly can't be ruled out at the moment.
 
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Old 05-13-19, 02:03 AM
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Are you on a well or city water?

Any water conditioning equipment!
 
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Old 05-13-19, 02:43 AM
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PS almost forgot -- I've got a well and not on town water. but again the cold runs clear.
 
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Old 05-13-19, 03:00 AM
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and no conditioning equip. water definitely on the hard side. Also, and this comes from ignorance, but what does flushing do that simply running the hot till it's cold wouldn't do?
 
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Old 05-13-19, 06:23 AM
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Not a pro, but algae would grow more in warm water as opposed to cold. I would consider shocking the well to clean the source and then hopefully that treatment will also help to clear the tank.

Run a bucket of cold water and set it out in the sun to warm up. I suspect it will grow algae. I know filling a pool from a well can be a disaster.

Bud
 
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Old 05-13-19, 04:51 PM
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thanks all for the thoughts.

is there a simple way to test the water to see if it's copper from the pipes, or algae growing?

is there something to look for in inspecting the pipes? they're relatively new, and I don't see any corrosion on the outside. they're visible in the basement and accessible.

and as for flushing the tanks, what would that do that simply running the hot till it's cold not do?

is there any reason to suspect that the use of two tanks is making a difference?

thanks again!
 
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Old 05-13-19, 05:11 PM
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Flushing would clear out any sediment in the bottom but sounds like it isn't an old tank, less of an issue. The water in two tanks will be replaced less frequently thus just sitting there longer. Being warm and untreated, as in chlorine, makes it more vulnerable.

I mentioned shocking the well, do you know what that is.

As for determining what is in the water there are test labs that do that all the time, check any well driller or your town office for references. Was the water tested when you moved in?

Bud
 
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Old 05-13-19, 06:28 PM
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FWIW, flushing removes material from the bottom of the tank which is normally not removed by use of the heater. As I said, it couldn't hurt but I would not bet a dollar that it solves everything.

Knowing you're on a well, have you ever had the water analyzed?
 
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Old 05-13-19, 06:39 PM
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Bring both tanks to 140 degrees to kill bacteria then see if problem clears up. I suspect one tank is too cool and promoting growth.
 
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Old 05-14-19, 02:49 AM
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great thoughts thanks. really helpful discussion as well. this is why this place is great -- just to have smart folks bounce ideas rather than on your own is invaluable.
 
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Old 05-14-19, 02:52 AM
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PS -- i have shut-offs on the heaters and was thinking of shutting one down and seeing if it was isolated to one tank or the other?
 
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Old 05-14-19, 10:11 AM
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If it's that easy, that could yield some useful information.
 
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Old 05-14-19, 10:39 AM
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@greekrevival

"PS -- i have shut-offs on the heaters and was thinking of shutting one down and seeing if it was isolated to one tank or the other? "

Turning the heat off may actually increase the growth of whatever is in there. Isolate one at a time but keep the power on and as mentioned check the temperature settings. Be sure the tanks remain full of water anytime the power is on.

Drawing off a bucket full of cold water as I suggested is a non-invasive way to confirm the water supply is prone to algae, which I suspect it is.

Bud
 
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Old 05-15-19, 11:30 AM
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For what it's worth, I've never seen copper piping cause green water. It can often cause greenish blue flakes in the water and in filters/aerators, but it doesn't dissolve and doesn't suspend very well in water.

So I'd bet your greenish water is more of an algae or bacteria problem. (and the other replies point you in good directions!)
 
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