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Question DetailsAsked on 10/13/2015

we have black water coming from hot water tap and water is only lukewarm in all faucets in house.

For 2 days we have had our hot water sputter with a lot of air when we turn it on and the water comes out black at first. Now today we have barely lukewarm water coming out of all the faucets. We opened the lever on side of water heater and a ton of black water came out and its also only lukewarm. The washer doesn't have any water come out on the hot setting. Is there a clog or is the water heater bad, or both? We have well water and we are terrible at keeping up with salt in our softener. Could that have contributed?

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Here is a prior question with answer that might help -

If ONLY the hot water comes out black, that eliminates the well, pump, and pump pressure/air tank and associated distribution piping as well as the water softener (unless it is only on hot water tank feed side) as sources - which narrows it down to water heater or hot water pipes.

Black water means something corroding or building up for a long time, not a short-term issue like a clog - again assuming cold water is clear and that the water softener is on the cold water line to the house, not just hot water feed side. Could be iron or manganese bacteria buildup in the pipe that broke free somewhere, dirtying the line - but I would guess water heater is the issue.

And definitely yes - not maintaining the soft water absolutely could contribute to or cause the problem - soft water is as important to pipe and water supply system health as it is to taste and helping this get clean readily.

I would turn off the heat on the water heater till looked at - because a lot of sputtering (again, assuming only on hot side so low water in well/contaminated well water not the problem) I would guess you had so much sediment in the bottom of the water heater that it has started boiling at the bottom (assuming gas heater here) and has started going anaerobic (so would be stinky hot water), creating gas bubbles in the heater which then cause the sputtering when you first run hot water. This sort of overheating can cause catastrophic water heater failure, so I would shut off till checked out by plumber.

I would call a Plumber and have him check your lines (cold inlet and hot) for buildup - could be your lines are sedimenting with stuff getting through your water softener because it has not been maintained (either well sediment or mineral buildup), or could just be the water heater being dirty and maybe going anaerobic. Depending on how bad it is, just thoroughly flushing all pipes with maximum flow rate, flushing and cleaning the water softener (and refilling with the treatment media), and draining and chemically treating the water heater then chlorinating and reflushing the system might solve it. Typically about $300-500 charge for all those combined - get an estimate before starting work. Might also involve 8-24 hours out-of-service for your house water during chlorination to kill the bacteria in the lines/tank, if that is needed.

BTW - when lines are being cleaned dishwasher and fridge water/icemaker and washer and similar water-consuming appliances should be isolated until the lines are cleaned out and disinfected, then they should be flushed out (run an empty cycle) because otherwise they can get contaminated/clogged with debris from the lines. Because nothing is coming out on washer hot cycle, its water line filter (either at inlet of water hose or at the washer end) is apparently plugged already and will have to be cleaned out.

Of course, if the pipes are so badly corroded that they are getting blocked with buildup (especially with steel/iron pipes, usually to a much lesser extent with copper, rarely significant with plastic) then it may be that some piping replacement will be needed.

IF water heater is in bad shape it may need replacement - commonly in the $1000 ballpark if not more than 50 gallon. A quick visual check inside the pipes at a couple of fittings in the hot lines will let him know if pipe corrosion is a problem or not, or if it is just a water heater issue. If water heater issue and it is fairly new (say less than half life old) flushing and treating it may solve its problem (he should be able to tell with a fiber optic scope or bright penlight looking inside after flushing), but if badly corroded inside or the crown plate (bottom) is corroded and flaking or has a heavy buildup baked on that will not flush out then it should be replaced or same issue may happen soon again.

He should also check temperature setting on water heater - if set too low (below about 120-125) it can grow corrosion-causing bacteria - plus that low a temp promotes bacteria growth that can be dangerous, including Legionaires Disease bacteria.


Above was all about hot water system - if this is happening on cold water system too, then I would be looking at a corroded pressure/air tank at pump or well water very dirty due to collapse in well, heavy bacterial growth in well, or well going dry so pumping a lot of sediment. Running water full force into a glass bowl and letting it settle out for an hour or so would show if that is the case. Be sure to run the faucet a bit before test to flush out any dirt that might have gotten into the faucet spout from dirty hot water.

Answered 4 years ago by LCD


Not only could have contributed, possibly caused it - and could have caused significant pipe damage as well, especially if metal pipes. The water softener does not just provide "soft" water - it largely protect against mineral buildup and metal-eating algae buildup in the system.

If water coming out cold faucets is clear, problem is NOT the water supply or pipes (well/pump/line from pump) and is likely a gunked up water heater but sometimes can be buildup or blockage in the hot pipes, especially if kept below about 130 degrees for safety - some manganese and iron algaes grow a lot better in the hot system - which may or may not be curable without replacing the water heater. If heater was not used for a week or two before this that could be the problem too - may have gone anaerobic and needs flushing.

If both hot and cold water are black (don't drink it or cook with it BTW), then likely a well/pump problem or a general buildup in the pipes and/or water softener, which could be from letting it go a fair amount of time without replenishing the water softener, but could also be from iron, manganese or sulfide buildup in the well, a significant pH change in the well, or intrusion of contaminants into the well - both fertilizer residue in strength and sewage from broken pipes or leach field breakthrough can cause this.


If hot water only then I would thoroughly flush the water heater (using bottom drain and a hose, after it has cooled down a bit to prevent damaging hose). Then after about 50 gallons or more has been flushed (so 10-15 minutes full flow) I would run water full flow for several minutes at all hot water taps and tubs/showers and flush toilets. Including empty fill and drain cycles (don't have to go through washing) but with light detergent in washer and dishwasher - but try faucets first. If they do not come clean fairly quick, do not run washer or dishwasher - they will get contaminated with it.

If a LOT of debris and sediment comes out of the water heater, then it may be you were failing to drain it out of the bottom of the tank every year (or twice yearly in high mineral content/sediment areas) so it filled in the bottom so much it started to boil in the bottom of the tank because the sediment insulated the burner/element from the water - this will kick up the sediment and make it mobile, and cause boiling - hence causing a lot of bubbles in the hot side of the piping.


If cold water is black too, I would check outflow at the water softener drain to see if black, then turn valve to BYPASS and see if that is black. If bypass is not black (or maybe try an outside faucet if those come off "before" the water softener as they commonly do) - if bypassed or "before softener" water is clean then you softener probably went anaerobic and needs to be thoroughly flushed to drain and opened up and cleaned - owner's manual should say how to do that - then flushed again, then refilled with treatment media. First check the flush cycle to see if the timer is working right - if it does not backflush periodically as it is supposed to it can get fully crudded up with the contaminants it is catching.

If bypass/"before" water is black, track back to all available hose bibs/drain valves at pump/wellhouse to see if the pressure tank is the problem or if the black water is from the well. If problem is at the pumphouse then a Well and Pump contractor would be your usual repair category. Could be a problem with a filter in the wellhouse (if you have filtration there) needing media replacement, a rusted out pressure tank, or chemical/contaminant issues in the well itself. It can also happen if the water level drops way off (which can also cause air in the lines as the pump starts going dry during the pump cycle) and as air gets into the usually underwater parts of the well. More commonly red than bleck in this case but I have seen sooty black also as buildup in the well gets exposed to air and gets pulled through the pump.

Water softener problems would be a water treatment guy's area - water heater obviously a plumber if yuou need help there.

Answered 3 years ago by LCD

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