Low water pressure can turn everyday tasks into a hassle—whether it’s a trickling shower or a kitchen faucet that takes forever to fill a pot. The good news: most causes are simple to pinpoint and fix.
Below, our Pasadena Plumbers recommend a step-by-step approach to diagnose and solve low water pressure at a single fixture versus throughout your entire home. If you need a hand, Pershing Plumbing is here to help local homeowners get consistent, comfortable water pressure—quickly and safely.
Quick 60-Second Diagnosis
Before you grab tools, do this:
- Test multiple fixtures:
- If it’s just one sink or shower, it’s likely a local issue (aerator, cartridge, hose, or shutoff at that fixture).
- If it’s every faucet, it’s a whole-home issue (main valve, pressure regulator, filter, leak, or city supply).
- Check hot vs. cold:
- Low pressure on hot side only? Suspect the water heater, mixing valve, or hot-side scale.
- Try an outdoor hose bib:
- Good pressure outside but poor indoors often points to interior plumbing or a clogged fixture.
- Ask a neighbor:
- If neighbors also have low pressure, you may be experiencing a municipal supply fluctuation.
Our Pasadena Plumbers recommend starting with the simplest checks first—you’ll often find the fix without opening any walls.
Fixing Low Water Pressure at a Single Fixture
Common culprits for one slow faucet or shower:
- Clogged aerator or showerhead
- What happens: Mineral scale and debris reduce flow.
- Fix:
- Turn off the faucet. Unscrew the aerator or showerhead.
- Soak parts in white vinegar for 30–60 minutes; scrub with a toothbrush.
- Rinse and reinstall with fresh plumber’s tape if needed.
- Pro tip: Our Pasadena Plumbers recommend installing a flow-optimized, easy-clean showerhead in homes with hard water common across SoCal.
- Partially closed angle stop (under-sink shutoff)
- What happens: The small valve under the sink or behind the toilet isn’t fully open.
- Fix:
- Turn the handle counterclockwise fully open. For quarter-turn valves, align the handle with the pipe.
- Check both hot and cold.
- Kinked or clogged supply hose
- What happens: Flexible hoses to faucets can kink or clog with debris.
- Fix:
- Inspect hoses for sharp bends or corrosion. Replace if old, rusted, or kinked.
- Clogged cartridge or diverter
- What happens: Modern faucets and many tub/shower valves use cartridges that can clog with sediment.
- Fix:
- Shut off water at the fixture. Remove handle and trim per manufacturer’s instructions.
- Pull the cartridge, soak in vinegar, rinse, and reassemble—or replace the cartridge.
- Tub/shower issues may involve the diverter sticking; clean or replace as needed.
- Safety note: Our Pasadena Plumbers recommend covering the drain to avoid losing small parts, and taking a quick photo before disassembly for easy reassembly.
- Debris after recent work or shutoff
- What happens: Sediment loosens when water is turned off/on and gets trapped in fixture screens.
- Fix:
- Flush lines: remove aerator/showerhead, briefly open water to blow out debris, then reinstall.
If one fixture still has low pressure after these steps, there could be hidden corrosion in the branch line, especially in older Pasadena homes with legacy galvanized piping. Pershing Plumbing can verify with pressure and flow tests and replace only the affected section if that’s the issue.
Fixing Low Water Pressure in the Whole House
If every fixture is weak, focus on these:
- Main shutoff or meter valve partially closed
- What happens: After repairs, valves may not be fully reopened.
- Fix:
- Locate your home’s main shutoff (often near the hose bib or where the line enters the house) and turn fully counterclockwise.
- If the street-side meter valve looks misaligned or damaged, call the city or Pershing Plumbing—do not force municipal valves.
- Failing pressure reducing valve (PRV)
- What it is: A bell-shaped regulator near where water enters the home; keeps pressure around 50–70 psi.
- Symptoms: Housewide low pressure, pressure that fluctuates, or noisy pipes.
- Fix:
- Our Pasadena Plumbers recommend checking pressure with a $15 gauge on a hose bib. Static pressure should be roughly 50–70 psi.
- If it’s too low and adjustment doesn’t help, the PRV may need service or replacement.
- Whole-house filter or softener restriction
- What happens: Cartridges clog, bypasses get mis-set, resin beds channel in softeners.
- Fix:
- Replace filter cartridges; verify orientation and flow direction.
- Check that softener/bypass valves are set correctly. Temporarily bypass to test pressure.
- Hidden leak reducing pressure
- Signs: Constant water meter movement when all fixtures are off; damp spots; unusually high water bill.
- Fix:
- Turn off all water, watch the meter. If it spins, you likely have a leak.
- Our Pasadena Plumbers recommend immediate leak detection to avoid structural damage and mold.
- Water heater restrictions (if hot side is low everywhere)
- Causes: Sediment in the tank, a clogged heat-trap nipple, or a mixing valve issue.
- Fix:
- Flush the water heater annually; inspect inlet/outlet fittings.
- Consider a scale-reducing device if you have recurring sediment.
- Aging galvanized or undersized piping
- What happens: Old galvanized steel corrodes from the inside, narrowing the pipe and starving flow.
- Fix:
- A repipe (often with copper or PEX) restores both pressure and water quality.
- Pershing Plumbing can map your system and prioritize the worst runs to control costs.
- City supply issues
- Sometimes low pressure is temporary due to municipal work. If your gauge shows a big drop at the hose bib, call Pasadena Water and Power or contact us to confirm.
How to Measure Pressure Like a Pro
- Attach a pressure gauge to an outdoor hose bib.
- Static test: All fixtures off. Healthy homes typically read 50–70 psi.
- Dynamic test: Open two indoor fixtures; pressure should stay reasonably steady. Large drops indicate flow restrictions or undersized/corroded piping.
- Our Pasadena Plumbers recommend keeping pressure under 80 psi to protect fixtures; if it’s higher, a PRV installation or adjustment is smart.
When to DIY vs. Call Pershing Plumbing
DIY-friendly fixes:
- Cleaning aerators and showerheads
- Opening shutoff valves
- Replacing faucet cartridges and supply hoses
- Swapping whole-house filter cartridges
- Basic water heater flush (if you’re comfortable and have a drain plan)
Call the pros for:
- PRV diagnosis/replacement and pressure balancing
- Housewide low pressure without an obvious cause
- Suspected leaks (slab, wall, or yard)
- Galvanized-to-copper/PEX repiping and manifold upgrades
- Water heater mixing valve or heat-trap issues
- Recirculation systems and balancing problems
Our Pasadena Plumbers recommend addressing pressure issues early—solving restrictions now prevents bigger problems like pinhole leaks, fixture failure, and water heater stress.
Pasadena-Specific Tips
- Older homes in Pasadena often have partial galvanized branches. Even if most of your home is copper or PEX, one clogged galvanized section can throttle a whole bathroom.
- SoCal’s hard water encourages scale buildup in aerators, cartridges, and heaters. Annual maintenance pays off.
- If you’re renovating, consider upsizing key runs and adding a pressure-balanced manifold for even flow when multiple fixtures run.
Preventive Maintenance Checklist
- Clean aerators/showerheads every 6 months.
- Replace whole-house filter cartridges on schedule.
- Flush the water heater annually; add sediment traps if needed.
- Test home pressure with a gauge twice a year.
- Inspect and operate shutoff valves so they don’t seize.
- Our Pasadena Plumbers recommend documenting your baseline pressure—changes are easier to spot when you know your normal.
Ready for Reliable Pressure? Pershing Plumbing Can Help
Whether you’re dealing with one stubborn faucet or the whole house is underperforming, Pershing Plumbing brings local expertise and fast, friendly service. Our Pasadena Plumbers recommend starting with a quick pressure test—then we’ll target the fix, not just the symptom.
- Fast diagnostics and upfront pricing
- PRV service, leak detection, filter/softener tuning
- Fixture repair, repiping, and water heater maintenance