Because you are saying it is the hot water that is doing this, it sounds like your hot water heater has built up sediment in it. How old is the hot water heater? Furthermore, a tank hot water heater has an element within it that collects the water's minerals, and eventually "gives its life up" for those minerals. The less-expensive tank hot water heaters have much thinner elements, so they wear through much faster, on the order of 3 years vs 12 years for the more expensive tank heaters with thicker elements.

I would start with looking at your hot water heater, its age, and its warranty life (there should be a label with that information on the tank). The longer the warranty life, the thicker and longer-lasting the mineral-collecting element within the tank. Also keep in mind that sediment build-up in a tank hot water heater is the main cause of heater water leaks, which you really do not want. It may be time to buy a new hot water heater, and try to get one with a long warranty, 10-12 years.

Thank you for this information. Everything was installed in our home three years ago when we bought it, as it had been just a shell--a model home. The water heater was brand new, too. We've already had that "element" within the eater heater cleaned out twice (I think it had to be replaced; not sure). So frustrating.

Perhaps we should invest in a more expensive water heater than can better stand up to the well water.

The good news is that the HOA recently voted to have our street hooked up to city water, about a year from now. I've heard that the city water is much cleaner. So we've just got to deal with this until then.

I know very little about hot water heaters. I just asked, and discovered that ours is called "on demand" and "heat exchanger." I was mistaken to think it had been replaced. The entire thing, which is compared to a car's radiator, had to be cleaned. The process took half a day, during which we had no hot water.

I guess there's something within it like tubing? And little propellers (?) which are supposed to keep the water churned up so nothing settles. But of course the hot water is not always running! So the minerals do settle. It gets totally clogged to the point that hot water no longer passes through. Something called "Scale X" was installed after the first time, but it made no difference.

I'm still curious, though it makes no practical difference, why the water runs orange when I first turn on the laundry sink faucet, then runs clean. Maybe I'm seeing the mineral-laden water that's been sitting within the water heating device? Maybe some of it coats the pipes, so even after it's finally run clean, turning the water on full blast sort of scrubs some more off the inside of the pipe...

I have no way to estimate how quickly the orange gunk accumulates; I keep wondering if the initial hot wash water is clean (thanks to me), but by the time the washer asks for warm rinse water it's gunked up again and flows yellow onto my clothes. Pure speculation, I know, so I keep using three cold water rinses at the end of each washer load though it feels wasteful.

What brand is your laundry sink faucet?

If the name is written on the faucet somewhere, I can't find it. What might be wrong with it?

We don't have a filter on it (the other faucets' filters do get clogged). I think the problem is general. Toilet porcelain gets clouded by the minerals; now and then every faucet in the house has spewed orange; and both the bathtub and the walk-in shower have orange stains I can't clean off.

I think your water has a high content of iron. I also are on well water and toilet and shower get an orange tinge if not cleaned often and sometimes water are clowdy from tap.

OK, your OP said "hot water tank", so I assumed it was a tank water heater. Now that you've added more information, it sounds like you need to get a "whole house water softener". It will treat all of the water that enters your home, both cold and hot. It not only will protect your tankless water heater, but also your appliances, plumbing pipes, and plumbing fixtures.

I also recommend you get in a licensed plumber - not a low-cost handyman guy, but an actual licensed plumber who has high ratings on yelp and Angie's List, is insured, and has many years of experience. He will be able to analyze much more what is going on than we possibly can over cyberspace.

Thankyou so much for your efforts to help me with this problem. Unfortunately, in our small, one-story home on a slab, there is absolutely no place large enough to install a whole-house or even partial house filtration system or water softener. :( We've tried. And yes, I called a licensed plumber.