I bought my house last summer, and immediately replaced all steel pipes with new copper. The buffalo box was inaccessible at the time, so the pipefitters used (and thus left) the old shutoff gate valve at the end of the lead service. Water pressure was improved, but still not ideal. Then about two weeks ago, the pressure dropped even more, and has not improved since. All fixtures in house are affected, both hot and cold water. I bought a pressure gauge at lowes, put it on an outside spigot, and it registered about 5 psi. I have removed the aerators in the kitchen and bath to improve flow, but the toilet usually cannot fill.
I called the city to have them check it out, and they do not think the problem is on their end (of course). So my question is could the culprit be the old valve and/or what appears to be a short section of steel leading into it from the lead union? Or is it more likely that there is an obstruction in the water main (under basement floor)? I'm lining up plumbers to consult, but I'm trying to rule things out or identify other possible culprits. (I tried to upload a photo, but was unable to.)