Quick Answer
Low flow at one fixture often comes from a local restriction such as an aerator, showerhead, supply valve/line, or cartridge. Whole-house low pressure or flow can involve utility supply, elevation, a building valve, a PRV where one is installed, a service-line restriction or leak, or internal piping. A pressure reading and symptom pattern help separate these causes.
Common Symptoms
- •Weak shower stream
- •Faucets take forever to fill a glass
- •Whole house feels low
Possible Causes
- •Clogged aerator or showerhead
- •Failing pressure regulator (PRV)
- •Partially closed main shutoff
- •Scale buildup in older galvanized pipes
Safe Things You Can Check
Test pressure at an outdoor spigot with a gauge — ideal is 40–60 psi.
Unscrew and clean faucet aerators and showerheads.
Confirm the main shutoff is fully open.
WHEN TO CALL
If the whole house remains low after simple external checks, we compare static and flowing pressure and evaluate the utility-side conditions, building shutoff, PRV where present, service line, and piping before recommending a regulator replacement or repipe.