Yes it’s definitely a HUD report. I’d be more worried about their Lead Paint findings than the pressure problem. Finding the pressure problem is as simple as turning on the main water valve. You’ll definitely find the leak once you do that! Don’t let plumbing scare you, it’s definitely not rocket science and fixing pressure lines are no problem at all. Generally it’s much more of a pain in the butt to fix the hole in the wall you had to create to get to the leak rather than fixing the leak itself.
Make sure you find out about your Lead Paint Abatement rules in your municipality, though, as I can almost guarantee that HUD found lead paint in that house if it was built prior to 1978. Some cities all you have to do is have the paint in good condition with no peeling or flaking. Some cities are much more difficult, though, and require you to remove ALL the leaded paint using a lead paint abatement certified contractor, which can cost over $10,000! I know in my city, Milwaukee, there are grants available for this abatement which will cover most of the cost if you qualify.
Out in California we have the detection service. Usually for a few hundred dollars the service will least tell you where the leak is. Fixing it could cost a around thousand if it’s only one and would be really hard to get to (appliance or caninet removal, drywall removal and replacement, stuff like that. Without a really good leak detection and a really good plumber with a really confident bid, ask what it will cost to replumb the whole building. Then at least you know what a worst case scenario would be.
Licensed master plumbers have tools to detect leaks. Cost probably depends on how much time it takes to check the system. We had a leak in a house a few years back and it was a few hundred dollars just to detect the leak.
You should expect to pay up to $1,000 to find and repair the leak if that’s all it really is. It could just be a faulty shut off valve or faucet that is causing the leak.
I agree with the other responses; I wouldn’t worry too much about. Just make sure you leave room in your budget to take care of the repair and be conservative in your estimate.