Totally agree about the regulator valve—seen that issue plenty of times. One other thing I'd toss in: sometimes older galvanized pipes can cause weird pressure drops, especially if they're corroded inside. Had a customer last month with similar symptoms, regulator was fine, but turns out the pipes were almost completely blocked up. Hopefully that's not your issue (fingers crossed), but worth keeping in mind if the regulator checks out okay...
Yeah, the galvanized pipe thing is definitely something to keep an eye on. Had a similar situation a few months back—customer was convinced it was the regulator, but after checking everything out, turned out it was actually sediment buildup in the water heater causing pressure issues. I was skeptical at first because usually sediment just affects hot water flow, but in this case, it was severe enough to mess with overall pressure.
Not saying that's definitely your issue, but it's another angle worth considering if the regulator and pipes check out fine. Also, don't overlook simpler stuff like partially closed valves or even faulty shut-off valves. I've seen cases where someone accidentally bumped a valve handle just enough to restrict flow without realizing it. Sounds silly, but you'd be surprised how often that happens.
Anyway, hopefully it's something straightforward and not corroded pipes—those replacements can get pricey real quick...
Had sediment issues myself, but honestly, I'd be pretty surprised if it affected overall pressure that much. Usually, it's just hot water flow. I'd double-check the main shut-off valve first—those things can be sneaky...
Had a similar issue once, turned out to be a partially closed valve under the sink... took forever to figure out. Did you already check all your fixture stops individually?
Had something similar happen a while back—checked all the fixture stops, valves wide open, still no luck. Turned out it was sediment buildup in the aerators. Took them off, soaked in vinegar overnight, and boom... pressure restored. Might wanna give that a shot if valves aren't the culprit. Plumbing mysteries, gotta love 'em.
