For at least the past 20 months, we have had a problem with our plumbing. When hot water is run through specific faucets (guest bath, downstairs lav), it will often have black flecks in it. They are kind of greasy when I clean it up, but I'm not sure if its charcoal or rubber. DH did some reasearch on it last year and could fix what he thinks it is, but after this long, I'm about ready to have a conniption. Several times it has screwed up bath time for DS, and its a b to clean up. So would you just ramp up the reminders for DH, call a plumber, or something else? (I would try to fix it myself but would have to learn how to plumb withcopper piping.)
Re: Speaking of DH Vents, WWYD
We replaced our water heater 3 or 4 years ago. We didn't have the problem until at most 2 years ago. When DH was researching the issue, he decided it could be one of the flexible pipes that he used b/c it has rubber gaskets or lining or something that some people report breaks down over time. When he went to Home Depot to get parts, the "expert" convinced him that couldn't be the problem, so he came home empty-handed. That's one person I'd better never meet in a dark alley! I still think that replacing that piece would be a good starting place, but it would have to be replaced with straight copper piping to figure out if that's really the problem or not.
It was copper piping too. Apparently it can be really tricky to get good seals without soddering it. So DH ended up buying "fancy" re:expensive parts for the whole deal. That a real plumber wouldn't have had to buy. But still cheaper than a plumber... I think....
Hot water heaters need to be drained yearly because they can build up sediment in the bottom of the tank which can 1: dump into the bathtub/sink and 2: take up room in the tank that hot water should be occupying. It can also cause hot water heaters to break prematurely.
I've had sediment dump out in the bath on a few occasions in different houses (we're military and rent a lot...) but I don't remember it being greasy or sticky so I'm not sure this is what it is for you, unless maybe your particular brand of sediment is greasy and sticky. For me, it was kinda just like a black cloud of octopus ink in an already halfway full or fuller tub so I'd just drain it and start over since it rinsed out easily with the water. Just wanted to throw that out there since nobody has mentioned tank sediment.