I'm writing this in the hopes that someone out there might have a little bit of an idea about what's going on. We live out in the country and have well water. In the fall of 2007, the water pump was replaced. Things have gone fine until about a month ago. Out of the middle of nowhere, we lost about 80% of the water pressure to the hot water only, cold water pressure is perfectly fine. This happens in every area of the house, even the bathroom that is right next to the hot water heater and the other bathroom that is directly above the water pump. It never varies, it's always the same.
Our landlord has said more than once that when the weather gets warmer, he'll come down and see what can be figured out. See, the house has a crawl space and not a basement and access is only from outside of the house and apparently he doesn't want to get cold working down there (rolling my eyes here). My hubby has torn the hot water heater apart, checking everything that could possibly be clogged or broken, and everything checked out fine. He has also opened up the valve on the bottom of the hot water heater and drained it. We've also went down into the crawl space and checked the pump and it's perfectly fine, since the cold water is good, we figured it would be. But nothing we have done has made it any better, if anything it's getting worse.
While I understand that our landlord is legally responsible for fixing this, I'm honestly tired of waiting and getting fed up. If anyone has any tips I'd really appreciate them. Short of replacing the lines, we don't know what else to do at this point. Thanks in advance for any help or tips!
I too have suffered with the same mystery. The cold has fine pressure, the hot about half as much. I've replaced copper plumbing as far as I could, but still cannot understand the mystery.
I will be looking at this post to see if someone has the answer.
OK, I need to "change" a little bit about my original post. Just for kicks and giggles we decided to empty out the shower in the back bathroom that has only been used for storage because we were told it had no water pressure and they had removed the shower head from it before we moved in here, 18 months or so ago.
We put a brand spanking new shower head on it and VOILA, we have water pressure respectable enough to take a decent shower. So now I'm totally confused. The hot water pressure sucks in the front shower and bathroom sink, at the kitchen sink and at the back bathroom sink, but in an unused shower it's pretty decent? Actually, now that I've "written" that, it makes me wonder if there hasn't been some sort of deposit build up in the pipes that have been used regularly VS the pipes to the shower that hasn't been used in God only knows how long? OK, first child just got out of the shower and proclaimed "That's the best shower I've had all winter". Sometime tells me we've got a ton of pipes that need replacing!
EDIT: "Sometime" should read "Something"
Calcium or mineral deposits clogging the tank?
Agreed with ToledoLatina. This area is pretty notorious for mineral deposits in groundwater that eventually work their way into your plumbing and all devices that are connected to a water supply. When I was in the restaurant business we had to get our ice machines serviced every year or so to clean out the built up calcium deposits.
The white gunk you see in the shower head is solidified calcium with perhaps some magnesium and/or iron present. Ultimately you should be using a water softener to reduce the mineral buildup.
As far as your unused shower, it might have better pressure simply because less water traveled through the pipes over the years. Also, unscrew the aerators on the other sinks and shower heads to see if they, too, are clogged with gunky white mineral deposits. Sometimes just a slight amount of buildup on an aerator (the little screen at where the water comes out of the faucet) can almost completely destroy water flow.
Quick image how-to for those unfamiliar with this process:

I'm thinking along the same lines, especially now since I have also taken a shower in the back bathroom. Granted, it's still a bit "touchy" temperature wise, but there is definitely quite a bit more pressure.
I agree about the water softener, sadly there is nowhere to put one. In the house that we moved from there we put in a fantastic Culligan reverse osmosis system that we'd have loved to have brought here. But there literally is nowhere to put it. Fortunately, the well water here isn't that "hard", and has none of the trademark "rotten egg" smell or coloring. It's crystal clear and we even drink it.
Another quick pic of a faucet aerator for those who know what it is but who never heard the term for it:

Not all hardwater has the rotten egg odor, which is associated with the presence of hydrogen sulfide. Iron will leave rust-colored stains, while calcium and magnesium leave powdery stains on your glassware (plus those aforementioned annoying gunk buildups on aerators).
Let us know if taking off the aerators temporarily works, Holly. I'd advise against making this a permanent solution, since aerators are designed to give your faucet extra water pressure while conserving water. Without the aerator in place, it takes almost double the amount of water usage to take your morning shower or scrub the dried cheese from the plate of nachos your kid zapped in the microwave for three mniutes.
Not to mention the children in developing nations who will never have the water because it is wasted (guilt time) or your higher water bills (common sense time).
:-}
We clean/change the aerators regularly, that was the first thing we did when this first started, but they were all clear of any type of build up
We don't have the powdery stains on the glassware. I'd love to get our water tested just to see what type of deposits it has in it!
Here is some information on getting Ohio water tested. It will cost a few bucks, but it might give you some peace of mind.
Unless they find uranium-235 or something.
:-}
I can't add much, the above are all very good suggestions and will probably result in finding the answer to your problem. Be careful though, it may be a rogue water snake stuck in your plumbing. They seem to like the warm water pipes best.
I used to live in the country and have well water. I never did take the time to learn a lot about wells and their operations ~~ but I DO know that your landlord might need to install a pressure tank; OR your landlord may need to have the bore holes cleaned in the bottom of the well due to sediment. Either way ~~ that might fix the problem.