Why Is My Water Pressure Low?

The answer decides whether you look at a screen or a valve.

Try hot and cold separately at several fixtures on different floors. One fixture weak on both temperatures points to that fixture. One temperature weak everywhere points at the heater side or its shutoff. Everything weak everywhere points at the main supply, the shutoff valve, or the pressure regulator.

A 2.0 gpm showerhead is not a broken 2.5 gpm one.

Federal standards cap showerheads at 2.5 gallons per minute, and EPA WaterSense labeled models are certified at no more than 2.0 gpm while being tested for spray force and coverage across a range of pressures. A recently replaced fixture that feels weaker may simply be delivering less water by design. Measure flow with a bucket and a timer; measure pressure with a gauge.

Aerators and screens collect debris, especially after work on the line.

Unscrew the faucet aerator and rinse the screen; do the same for a showerhead where the manufacturer allows it. Sediment released by nearby main work, a heater replacement, or a repaired break lands in these screens first, which is why a sudden whole-house drop often shows up fixture by fixture.

A partly closed valve looks exactly like a supply problem.

Confirm the main shutoff and any fixture stop valves are fully open; a valve knocked partway closed during other work is a common cause. Where the home has a pressure-reducing valve, a failing one can drift low or high over time. Adjusting or replacing a regulator, and any work on the meter or service line, belongs with a licensed plumber or the water utility.

A gauge reading turns a complaint into evidence.

Thread an inexpensive pressure gauge onto an outdoor hose bib or laundry connection and read it with everything else off, then again while a fixture runs. Note the two readings, the time of day, and whether neighbors report the same. That record shortens the conversation with a plumber or the utility considerably.