One affected outlet can reflect a clogged aerator, local stop, cartridge, or small branch restriction.
EPA notes that home fixtures generally operate best with incoming service pressure in a defined range and describes checking with a gauge at a hose bib while other uses are off. A single reading is evidence, not a full diagnosis; dynamic behavior and the gauge condition matter too.
Keep this boundary: Flow and pressure are related but not identical. A blocked aerator can feel like low pressure even when building pressure is normal.