Clothes don’t really need hot or warm water to get clean. Most detergents work fine in cold water. And the temperature that hot water heaters produce is close to optimal for bacterial growth.† So try washing everything in cold water and see if they come out just as clean.
†Not all bacteria, but pretty much all the bacteria we worry about.
If you have a slab house and the cold line is leaking then what are your plans? If it involves digging up the slab I would consider running a new line through the attic and build a box structure around it. foam the outside of the box with spray insulation and put ceiling vents underneath the box so the house heats the pipe.
That is the big question. We had to hire leak detection specialists to pinpoint the leak location. Depending on what they found, we then would have to make the tough call, along with the plumbing company we’re working with. Dig up the slab? Reroute the plumbing? We had part of our attic remodeled into a finished loft space so running pipe through it may be a problem.
As it turns out, the leak detectors were here yesterday and they determined it’s from a capped-off dead end line that runs off the kitchen sink line. So the plumbers may be able to deal with it without causing major damage to the house. Yes, even if it works, it’s a stopgap solution that doesn’t address the 70+ year old galvanized lines (which are only in the older central part of what is a ‘sprawling ranch’ with 2 later wings added, all copper lines in the newer wings).
But we also have a failing furnace that’s getting replaced next week, so if we can stopgap the plumbing leak and pray for the rest to hold for another year or so, we might just do that. Getting house repair fatigue, not to mention watching our rainy day fund be steadily depleted 
Are you getting a heat pump instead of another furnace? Assuming your old furnace is natural gas, a heat pump would save you money, since electricity is cheaper than gas. Also they do both heating and A/C.
Hmm, a heat pump wasn’t even on our radar. We already have a furnace ordered through our HVAC guy, who’s taken good care of us with our heating and cooling maintenance needs over the years.
I did a bit of googling just now-- heat pumps sound great in theory, but are expensive to install, have possible maintenance issues, and apparently don’t do too well in cold climates. Also, I don’t feel like taking a left turn and trying to work out the logistics of getting a heat pump installed. It’s getting cold, so we need heat that works, and soon.
That’s not true. You might get by in the southern states but a heat pump becomes less efficient as the temperature drops. And in the event of a power outage you can run a generator to power a gas furnace and also a gas fireplace if you have one.
If you want to run a geo-thermal system then it will be more consistent as the temperatures drop. But if you run an open loop well system then you have to be prepared to back-flush once a year. Not the easiest thing to do.
You could also run it through your walls above the door headers. Basically you’d cut the drywall at top of the walls in a clean line and run the new flexible line through the studs. You would have to drill a hole in each stud for it to pass through which is something you could do yourself. when it’s done you drywall it back up. Many houses are set up with a central layout for water so it shouldn’t be the house-destroying project that it sounds like. You might check with people who do drywall for a living. This is something easy for them to do. the nice thing about the new flexible lines is that you can run them around corners without any fittings. Less likely to leak.
I hope you have a dielectric connection where the copper and galvanized pipes are connected.
You got me worried with this statement! But the plumber came back, and I confiremed he did do dieelctric connections between the copper and galvanized.
He was able to get to and fix the latest local leak, so we settled for a stopgap that fixes our problem for now, until the next weak link in the galvanized lines springs a leak. the plumber said the galvanized pipes themselves still look really good, very little corrosion-- the problems are happening at the joints.