Why Is My Water Pressure Low?
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.
- Weak shower stream
- Faucets take forever to fill a glass
- Whole house feels low
- —Clogged aerator or showerhead
- —Failing pressure regulator (PRV)
- —Partially closed main shutoff
- —Scale buildup in older galvanized pipes
- ✓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.
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.
Related professional service
Reviewed by Paul Hall, Owner & Licensed Plumber
The Classic Plumber · Knoxville, TN · License #4268
Rather have us handle it?
Request service from The Classic Plumber — we'll diagnose it properly and fix it right.