Oily discharge from bathtub faucet

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  #1  
Old 04-06-10, 04:54 PM
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Oily discharge from bathtub faucet

Every week or so, I turn on my bath faucet (hot water side) and an greyish-blackish oily discharge comes out, then clear hot water. I had this now 4 year old hot water heater disconnected overnight by a plumber who moved it a few feet away to allow AC lines to be installed. Then the gas fired water heater was returned to its place. The plumber also replaced the turn off water valve as it was frozen. He also connected the overflow pipe to drain that the original homeowner never bothered doing. Yes, our area also had a junction water line repaired that required shutting off our water for 12 hours to allow the glue to dry after the fix. I can't decide if it was my moving my water heater that is causing this, or if the plumber left to much flux while soldering, or if its related to the water pipe repair. The tank was moved well over a year ago for the AC lines install, yet it's STILL OCCURRING! If you think my problem is unique, read this post because it's exactly my situation. The reply he got from 5 plumbers had no definitive explanation.

"Approximately every 2-3 weeks, generally when I am about to take a hot shower, the hot water comes out of my faucet with a black discharge... it looks like soot, but seems more oily. It's been going on for about 5 years... I've asked numerous plumbers and they have no idea what it could be. Last year - during a repair, a plumber noticed that the backflow valve from my boiler wasn't installed and supposedly fixed that ... and we thought that would resolve the problem. It didn't. Several other plumbers said that it was my hot water heater breaking down and I needed a new one.
About a month ago I came home to find my hot water leaking heavily from the release valve so I turned it off and decided it was time to go ahead and replace it (it's about 14 years old) - thinking that it would also correct the discharge problem. Lo and behold - two days ago... black discharge in my hot water..."

ANY IDEAS, please reply with informed suggestions, not total guesses.
Thanks!
 
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  #2  
Old 04-06-10, 08:32 PM
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This isn't the right forum for this question, but things a little slow around here right now, so I'm gonna humor this thread for a bit, simply because I have an interest in it... and now I'm gonna ask you some questions...

What is the source of your municipal water? (I'm assuming that you are not on a private well, you would have mentioned that if you were, right?) In other words, does your town get it's water from wells, or reservoirs?

Has anyone ever checked the sulfate levels in the water supply?

What is the general geographic location of this water supply? ... if you don't want to be specific and tell us exactly...

I'm GUESSING! ha ha that if you took a water sample, and had it run through a water testing lab, that you would find high sulfates in the water. In fact, I am going to suggest that as your course of action. Whatever is coming out of that tap is in the water... makes sense, right? So the only way to NOT guess is to do analysis on what is IN the water.

Does your hot water ever have a 'rotten egg' smell?

It probably did not with the old heater, because your anode rod was no doubt gone after 14 years... but what about the new heater? Do you know if the anode is aluminum, or magnesium?

By the way... the leaking discharge valve... is there an expansion tank on the cold line into the water heater? There are two things that will open that valve, over PRESSURE, or over TEMPERATURE. If the thermostat on the heater 'stuck' and the water overheated, it would open. Likewise, if the system pressure went over 150 PSI (I think that's the rating on the valve... maybe 125...) it would open.

I'm going to eventually move this to the 'water heater' forum, but I'd like to hear/see your answers before I do!
 
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Old 04-06-10, 09:56 PM
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You know, I have a thought, but changing the water heater would have fixed it "possibly". I have never run into this but have heard of this... If the water temp is kinda low in you hot water tank a type of bacteria can grow, and also be unhealthy. If it were in the tank for a long time there may be some in the hot piping of the house. Replacing the tank would not clear the pipes. The only way to eliminate it is to disinfect the piping with chlorine or bleach.
 
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Old 04-06-10, 10:42 PM
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The other guys problem is in quotes below my post.

So. Calif. city water, condo. 4 or 5 year old gas heater, no other problems.

One common thing between him and I, this doesn't happen at our sinks. It's the turning on of our hot water bathtub faucets which puts out the water with more volume and pressure(?). I don't really hear any "spurt" sounds or air tho. Another note, I took a shower with it not happening in the morning, then later that night that stuff came out. It lasts for about a second or so, then maybe another sec, then clear. Greyish black in color. There are some tiny black bits left after the water runs down the drain, and when wiped, smear like grease. The frequency is hard to compute, maybe 2 or 3 times a month or more. Moderate to light daily usage of hot water.

I hope this helps.
 

Last edited by plex123; 04-06-10 at 11:02 PM.
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Old 04-07-10, 09:59 AM
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Yes, it's the higher flow when you open the tub tap that is breaking the residue from the walls of the pipe. I guarantee that if you open any one of your hot water pipes you will find that the walls of the pipe are covered with the black residue.

Mark is talking about SRB (Sulphur Reducing Bacteria)... and it's not particularly unhealthy, but it can create a 'bio-film' that is at the least, not pretty to look at. There are also IRB (Iron Reducing Bacteria) and they make an even slimier mess. (but still not particularly unhealthy)

What is the source of your municipal water? Reservoir or Well?

If you don't want to do the water analysis yourself, why not contact your water authority and ask for a copy of the latest quality report? This report may or may not contain the sulfate levels, as they may not be required to test for it. It's not really a health issue, just aesthetic.

I almost guarantee that you are going to find high sulfates in the water.

If your water heater has a magnesium anode, you might see some improvement by going to aluminum... maybe ...
 
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Old 04-07-10, 12:27 PM
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My source of water is the municipal city water plant, Colorado river water I assume.

I'm doubting this is a city water issue, as it is fed to nearly a million others. It's very hard water tho.

Have a look at this link: Is this the sort of thing you're talking about? Talks about temps and growth.
How To Remove Sediment from a Water Heater | How To Do Things.com

Edit: My water temp is 165 F. I'm going to reduce it. No foul smells at closet.
Also, the main pipe going into the heater has a hold down nut on the heater and its now all rusted and
bubbly crusting out. I should have that looked at.
 

Last edited by plex123; 04-07-10 at 12:58 PM.
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Old 04-07-10, 01:08 PM
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You may or may not have bacteria... if there are minerals in the water they can precipitate all by themselves from the water... and that website you pointed to seems like reasonable advice, but most of the 'sediment' they are talking about is the stuff that's in the water and collects at the bottom of the water heater for various reasons.

The black color can also be caused by MANGANESE in the water supply.

When I ask for the source of the water... What I'm trying to get at is whether they get the water from a reservoir system, or from drilled wells... and you don't know for sure...

I'm still telling you to call your water authority and ask them for the most recent analysis and see what the sulfate and manganese levels are in the water.

I'm doubting this is a city water issue,
What you see in your pipes is IN THE WATER TO START WITH! Where else is it coming from? Yes, your water heater being at 165 may contribute to the problem, and you might find that cranking the temp down solves your problem... if it does, great, but keep in mind that whatever is causing the black deposits is STILL IN THE WATER, but you can't see it because it is IN SOLUTION. Only when it comes out of solution, and changes state, do you see it. I'm sure it's not harmful to the health, just annoying...

It's very hard water tho
HARDNESS is MINERAL CONTENT, and those minerals are dissolved ... in some cases, it can be 'an issue'... such as when it precipitates out of solution and causes black deposits on the inside of piping.

Or, maybe there's an octopus in your water heater...

I'm moving you over to the water heater forum now...
 

Last edited by NJT; 04-07-10 at 02:28 PM.
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Old 04-07-10, 05:08 PM
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I'm glad to hear that you are lowering the setting of the hot-water heater. 165 deg is way too high! Try 120-125 deg.

I agree with Trooper - whatever the gunk is, the source has to be coming, originally, from your domestic water supply. Where else?

If all else fails, install a water softener or reverse-osmosis unit on the water supply to the water heater.
 
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Old 04-07-10, 07:25 PM
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I have to say this... I have the EXACT same problem with my hot water... that's why I was interested to see if there would be any other answers. I hesitated to admit this because I wanted to draw out any other opinions ideas, etc that I could. I'm on a private well, and the water is tested every few years. The sulfates and manganese in my water is very high, and that's what I attribute the black/gray and shiny black specks to. I've had the piping open on numerous occasions and can attest to the fact that the deposits are in the pipes, but from what I can tell, not so much in the heater itself. (I recently replaced mine, and sawed it open to look). There was very little in the tank itself, compared to the piping, and the problem continues with my new heater.

I do have a Zeolite based water softener that does a great job at taking out the carbonates, and most of the iron, but seems to have little effect on the manganese. There's probably a different resin that would work for that, but I don't have room for another tank.

I think the mechanism that causes the deposits is the COOLING of the previously heated water when it sits in the pipes. This seems to be when the manganese oxidizes and deposits itself on the inner walls of the piping.

plex, what's the inside of your toilet tank look like?

By the way, I did a little googling on "Southern California water quality" and found that at best, the water quality in your region is not rated very highly.

I don't imagine that the shaking of those century old water pipes helps your situation very much either.
 
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Old 04-07-10, 07:47 PM
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OK, the bacteria may not be a hazard and I know this does not pertain to this problem because we have determined it has a higher water temp. but, too low of a water temp can cause a bacteria that has been associated with a common health risk called Legionella. I call that a hazard...

[SIZE=2]"Legionella has been found in hot water tanks, hot water propelled from shower heads and faucets and in whirlpool spas. It is not known whether Legionella enters a building's water from municipal feeder systems or adjacent contaminated cooling towers. The use of hot water with production of aerosols allows Legionella, if present in the water, to get into the lungs." [/SIZE]
[SIZE=2] [/SIZE]http://www.ccohs.ca/oshanswers/diseases/legion.html

Next I would like to bring up the issue of the 165* water temp. There is absolutely nothing wrong with this output temp PROVIDED...
An Approved Mixing Valve, set at no more than 130* MUST be installed immediately after the water leaves the tank, with the exception of a high temp line run directly to the dishwasher if so desired.

What is throwing me off track here is the "Oily" feel to the discharge. That is why I was going towards the bacteria.

I will keep thinking.
 
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Old 04-08-10, 12:21 AM
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How about if I shut off main, remove the faucet valve, screw in a short 45 angle copper threaded pipe and turn the main back on and flush for awhile? Maybe the unimpeded full force of hot water might help.

I emailed my HOA manager a week ago to ask if any others were complaining of this problem in a 210 unit complex, apparently it's not a problem here.
 
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Old 04-08-10, 04:54 PM
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Right... legionella nothing to mess with... that site that plex posted did mention that. Said to run the heater at least 130, but I'm more comfortable with 140. Still, on a chlorinated municipal supply, 130 is probably fine. One thing to keep in mind about legionella is that it's not hazardous to INGEST, but when it becomes airborne, as in a nice hot shower, it's very dangerous. Low levels of exposure can usually be fought off by otherwise healthy individuals, and they may think they have a 'cold'... higher levels produce pneumonia like symptoms, and even healthy ppl can become VERY ill... or worse.

I run my system at 140, and still have the same problem, so I'm doubtful that lowering the temp will help much, if at all, but it's worth a try.

I don't really think the stuff is 'oily'... it only feels oily because the particles are so fine. They are water soluble, and clean right up with soap and water.

I've tried flushing the lines out... no joy... I've disinfected with both bleach and hydrogen peroxide... no joy. (although a few ounces of peroxide into the water heater kills the sulfur smell for 2-3 weeks)

I'm having a new well drilled this summer into a deeper aquifer, hopefully almost $10 grand thrown at it will help. The water at 250' is supposed to be pretty good. I hope so.

No, nothing wrong with running at 165 with a mixing valve, but surely running that hot uses more fuel, and 'standby' losses are much higher.
 
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Old 04-08-10, 05:01 PM
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  #14  
Old 02-20-15, 03:59 PM
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black deposits in hot water

I also had black 'oily' deposits in the hotwater. It started in the tub, but after a while started seeing it in other faucets. I was worried it was the hot water heater. However, I found the problem to be in the rubber hoses above the water heater going to the hot water lines. After tearing them out, I cut them with a hacksaw, and found them to be disintegrating. After running flushing out the line, there does not appear to be any more black deposits. If anybody has problems with black oil deposits, take a look to see if you have rubber hoses above the water heater, and replace them.
 
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