The answer to 'why is my pressure regulator clogged' is that pressure regulators can become clogged over time due to mineral buildup, debris, or corrosion in the water supply. This can restrict water flow and reduce the effectiveness of the regulator.
Some common symptoms of a clogged pressure regulator include low water pressure, fluctuating pressure, or the regulator making unusual noises. To fix a clogged regulator, you may need to disassemble and clean it, or in some cases replace the entire unit. If you're not comfortable doing this yourself, it's best to call a professional plumber to inspect and service the regulator.