Low water pressure is more than a daily annoyance—it can signal hidden leaks, aging pipes, or a failing pressure regulator that wastes water and money. In Pasadena, we see a core set of culprits pop up again and again due to older housing stock, hard water, and tree-lined streets.
Pershing Plumbing, your local Pasadena plumbing company, explains the most common causes of low water pressure, simple checks you can do safely, and when it’s time to call a pro.What “normal” water pressure looks like
- Most Pasadena homes perform best at 50–70 psi. Above 80 psi is not code-compliant and can damage fixtures; too low makes showers and appliances underperform.
- You can test with a simple pressure gauge on an outdoor hose bib. If results are consistently under 45–50 psi across the home, it’s time to investigate.
Low pressure vs. low flow: why it mattersMany homeowners say “low pressure” when the real issue is restricted flow at the fixture. True pressure problems affect multiple fixtures or the whole house.
Localized low flow is often caused by clogged aerators, shower-heads, or cartridges. Pershing Plumbing can help you pinpoint which you’re dealing with, but here are the most common causes.
Top causes of low water pressure in Pasadena
- Clogged aerators and showerheads
- Cause: Hard water minerals common in the San Gabriel Valley create scale that narrows openings.
- Signs: One or two fixtures are weak; others are fine.
- Try: Soak aerators and showerheads in vinegar, scrub, reinstall. If pressure returns, you’ve found the culprit.
- Partially closed valves
- Cause: Under-sink stops, toilet shutoffs, or the main shutoff can be bumped or left partially closed after a repair.
- Signs: A single room or fixture is weak, or the whole house is slightly underpowered.
- Try: Ensure fixture shutoffs are fully open and the main valve is parallel to the pipe (for ball valves).
- Failing pressure-reducing valve (PRV)
- Cause: The PRV (usually near the main or the meter) regulates city water down to safe levels. Over time, its internal diaphragm wears out.
- Signs: Whole-home pressure is low or fluctuates; you might also hear hammering or experience surges.
- Fix: PRV adjustment or replacement. Pershing Plumbing replaces PRVs to restore steady, code-compliant pressure.
- Aging galvanized steel pipes
- Cause: Many older Pasadena homes still have galvanized water lines. These corrode internally, closing the pipe down to a trickle.
- Signs: Progressive, house-wide decline in pressure and flow; brownish water at times.
- Fix: Targeted repipe of problem branches or whole-home repiping with copper or PEX. Pershing Plumbing can assess and phase work to match your budget.
- Hidden leaks and slab leaks
- Cause: Pinholes in copper, failed fittings, or leaks under the slab reduce available pressure and increase your bill.
- Signs: Unexplained water costs, warm floor spots, musty smells, hissing behind walls, meter spin with all fixtures off.
- Fix: Professional leak detection. Pershing Plumbing locates and repairs or reroutes lines to protect your foundation and restore pressure.
- Water heater restrictions
- Cause: Sediment buildup, a clogged heat trap, or a faulty mixing valve reduces hot-side flow.
- Signs: Low pressure on hot water only; cold is fine.
- Try: Flush the tank annually to reduce sediment. For persistent hot-side issues, Pershing Plumbing services water heaters (tank and tankless) and replaces failing components.
- Clogged cartridges or fixture stops
- Cause: Debris or scale inside faucet/shower cartridges, or debris trapped in under-sink stop valves.
- Signs: One faucet or shower is weak, especially after recent work or a shutoff.
- Fix: Clean or replace cartridges and flush lines. Pershing Plumbing can service fixtures without damaging finishes.
- Whole-house filter or softener issues
- Cause: Old cartridges, clogged media, or a stuck bypass reduce flow.
- Signs: Whole-home pressure drops right after filtration equipment.
- Try: Replace cartridges, check the bypass, and verify service intervals. Pershing Plumbing maintains and reconfigures filtration to balance water quality and pressure.
- Backflow preventer or check valve problems
- Cause: Stuck, corroded, or incorrectly sized devices can choke flow at the main.
- Signs: Notable loss of pressure after recent irrigation/backflow work or new construction.
- Fix: Test and service by a licensed Pasadena plumber. Pershing Plumbing ensures compliance and proper sizing.
- Municipal supply fluctuations
- Cause: Peak demand, hydrant use, or maintenance can temporarily reduce street pressure.
- Signs: Pressure dips at certain times of day, then returns.
- Try: Note patterns. If it’s chronic, Pershing Plumbing can install or tune a PRV and advise on options like a booster system if appropriate.
- Irrigation or exterior leaks
- Cause: Broken sprinkler lines, hose bib leaks, or faulty anti-siphon valves divert water.
- Signs: Wet spots outside, hissing valves, or low house pressure whenever irrigation runs.
- Fix: Repair or replace the faulty components. Pershing Plumbing can separate and regulate irrigation zones to protect indoor pressure.
- Construction debris after plumbing work
- Cause: Scale or solder flakes lodged in lines after a repair.
- Signs: Immediate loss of pressure at one or two fixtures post-service.
- Fix: Flush lines and clean aerators/cartridges. If problems persist, Pershing Plumbing will clear affected branches safely.
Simple, safe checks before you call Pershing Plumbing
- Compare fixtures: Is it one faucet, one room, or the whole house? This narrows the cause quickly.
- Hot vs. cold: If only hot is weak, the water heater or mixing valve is suspect.
- Clean aerators: Soak and scrub with vinegar; replace worn washers if needed.
- Verify valves: Confirm under-sink, toilet, and main shutoffs are fully open.
- Do a meter leak test: Turn off all water. If the meter’s low-flow indicator spins, you likely have a leak and should call Pershing Plumbing.
- Measure with a gauge: Attach to a hose bib. Below ~50 psi across the home points to PRV, main, or leak issues.
When to call Pershing Plumbing, your Pasadena plumbing company
- Whole-home low pressure that isn’t tied to a single fixture
- Fluctuating pressure, banging pipes, or surges
- Signs of leaks, slab issues, or damp, warm floors
- Older galvanized piping with chronic weak flow
- Water heater that produces weak hot water only
- Filtration or softening equipment that repeatedly clogs or starves the home
How Pershing Plumbing restores strong, safe water pressure
- PRV inspection and replacement: We set pressure to the sweet spot for comfort and code.
- Leak detection and repair: Non-invasive tools find hidden leaks fast, including slab leaks common in Southern California.
- Targeted or whole-home repiping: Copper or PEX solutions designed for Pasadena homes, from historic bungalows to hillside builds.
- Fixture and valve service: Cartridge cleaning/replacement, stop valve upgrades, and shower/bath performance tuning.
- Water heater maintenance: Flushing, descaling, and mixing valve service for both tank and tankless systems.
- Filtration optimization: Correct sizing, media changes, and bypass configuration to protect flow and appliances.
Pasadena-specific tips from Pershing Plumbing
- Hard water accelerates scale. Annual water heater flushing and periodic showerhead cleaning go a long way.
- Many older homes still have galvanized sections hidden behind walls. Even a partial repipe can dramatically improve pressure.
- Code limits static pressure to 80 psi. If your home spikes above that, you need a working PRV to protect fixtures and prevent leaks.
- Know your main shutoff. In an emergency or for basic maintenance, this saves time and prevents damage.
Why homeowners choose Pershing Plumbing in Pasadena
- Local expertise: We understand the quirks of Pasadena’s plumbing—from vintage fixtures to modern remodels.
- Clear options: We explain the root cause and give you practical choices, from quick fixes to long-term upgrades.
- Respect for your home and time: Licensed, insured pros, clean work, and reliable scheduling.
If low water pressure is putting a damper on your day, Pershing Plumbing can help. From simple fixes to comprehensive solutions, we’ll diagnose the cause and restore strong, steady water throughout your home. Contact Pershing Plumbing—your trusted Pasadena plumbing company—for expert service and dependable results.