Why Is My Water Pressure So Low? | Los Angeles Plumber Explains Causes & Fixes
Why Is My Water Pressure So Low in Los Angeles? A Complete Homeowner’s Guide (And How to Fix It Fast)
Low water pressure is one of the most frustrating plumbing problems Los Angeles homeowners deal with. Taking a shower feels weak, faucets barely rinse dishes, and washing machines take forever to fill. But for many homeowners, the bigger frustration is not knowing why it’s happening or how to fix it.
JMS Express Plumbing—Los Angeles’s trusted plumbing company—responds to hundreds of low water pressure calls every year, and we’ve found a simple truth:
👉 Low water pressure is almost always a symptom of a deeper plumbing issue.
In a city filled with older homes, hard water, aging pipes, and constant construction, LA sees more water pressure problems than almost anywhere else in California.
If you’re wondering:
Why is my water pressure suddenly so low?
Do I have a leak?
Is something wrong with my pipes?
Can I fix this myself—or do I need a plumber?
This guide breaks everything down clearly so you know exactly what’s going on and what to do next.
Section 1: Understanding Water Pressure in Los Angeles Homes
Before diving into causes, it helps to understand how water pressure actually works.
Most homes in Los Angeles receive water from LADWP or a local water district at an average pressure of 60–80 PSI (pounds per square inch).
Good water pressure = strong flow from faucets, showers, and appliances.
Low water pressure = weak flow, slow-moving water, and inefficient fixtures.
Homeowners usually notice pressure drops in one of five ways:
Weak shower pressure
Faucets that barely trickle
Washing machines that fill too slowly
A drop in pressure when more than one fixture runs
Inconsistent pressure that goes up and down
These symptoms point toward specific causes—and in Los Angeles, those causes tend to follow predictable patterns because of the city’s age, water quality, and infrastructure.
Section 2: Top 10 Causes of Low Water Pressure in Los Angeles Homes
Cause #1: Hard Water Buildup (Extremely Common in Los Angeles)
Los Angeles has some of the hardest water in the United States.
That means:
Calcium
Magnesium
Mineral deposits
…build up inside faucets, showerheads, and—most importantly—inside your pipes.
Over time, these minerals:
Narrow the inside of pipes
Clog aerators
Restrict flow
Reduce pressure in one room or the entire home
Signs this is your issue:
Showerhead pressure is very weak
Faucets sputter or spray unevenly
White, chalky buildup on fixtures
Pressure drops slowly over months or years
DIY fix:
Soak showerheads/aerators in vinegar overnight.
Professional fix:
If mineral buildup is inside the pipes, JMS Express Plumbing can:
Perform a whole-home pipe descaling
Replace heavily corroded sections
Install a water-softening system
Cause #2: Old or Corroded Galvanized Pipes (Extremely Common in LA’s Older Neighborhoods)
Many LA homes—especially in neighborhoods like:
Los Feliz
Atwater Village
Hollywood
Sherman Oaks
Eagle Rock
Mid-City
Silver Lake
…were built with galvanized steel pipes.
These pipes corrode and rust on the inside, slowly choking water flow.
Symptoms of corroded pipes:
Brown or rusty water
Major pressure drop after turning water on
Hot water pressure much lower than cold
Pipes that “bang” or “groan”
This issue gets worse every year until the home eventually needs partial or full repiping.
Professional fix:
JMS Express Plumbing performs:
Copper repiping
PEX repiping
Sectional replacement
Whole-home repipes
Repiping instantly restores pressure and eliminates leaks and rust problems.
Cause #3: A Hidden Plumbing Leak
Low water pressure is often the first sign of a leak—long before water ever reaches the surface.
Leaks can happen:
Behind walls
Under slab foundations
In crawlspaces
In the main water line to the home
If water is escaping the system, less water reaches your fixtures, resulting in pressure loss.
Other signs of a leak:
Higher than normal water bills
Warm floors (hot water slab leak)
Sounds of running water
Wet spots or mold on walls
A drop in pressure in just one section of the home
Professional fix:
JMS Express Plumbing uses advanced leak detection equipment (thermal imaging, acoustic detection, and pressure testing) to pinpoint leaks without tearing open walls unnecessarily.
Leaks are one of the most urgent plumbing issues, and fixing them quickly protects your foundation, walls, and flooring.
Cause #4: A Faulty Pressure Regulator (PRV)
Most LA homes have a pressure regulating valve that lowers street pressure to a safe level.
If the PRV fails, water pressure may:
Drop dramatically
Become inconsistent
Affect the entire house at once
Symptoms:
Pressure high one day, low the next
Entire house has the same low pressure
Banging or vibrating pipes
A bad PRV cannot be repaired—it must be replaced.
Cause #5: Partially Closed Main Shutoff Valve
This is surprisingly common after:
City utility work
Home renovations
Emergency shutoff events
Someone bumps the valve accidentally
A valve that is even slightly closed can cut water flow significantly.
DIY fix:
Locate your main shutoff (usually outside near a hose bib or inside near the water heater) and make sure it is fully open.
Cause #6: Clogged or Old Faucet Aerators
The aerator is the small screen at the end of a faucet.
Hard water clogs these screens constantly in Los Angeles.
Symptoms:
One faucet has low pressure
Water sprays sideways
Unscrewing the aerator temporarily improves pressure
DIY fix:
Unscrew, clean, and reinstall aerators.
Cause #7: Municipal Water Issues (City-Side Problems)
Sometimes the problem isn’t inside your home at all.
Los Angeles frequently experiences:
Construction shutoffs
Hydrant flushes
Main line repairs
Temporary pressure drops
If your neighbors have the same issue, it’s likely city-related.
Cause #8: Failing Water Heater
If the hot water pressure only is low, but cold water pressure is fine, the water heater is almost always the problem.
Causes include:
Sediment buildup
Corrosion inside the tank
Partially clogged supply lines
Failing shutoff valves
JMS Express Plumbing can flush, repair, or replace the unit depending on severity.
Cause #9: Shared Pipes in Multi-Unit Buildings
Buildings in LA often have shared supply lines between:
Apartments
Duplexes
Fourplexes
If your neighbors shower at the same time every day, your pressure drops.
Solutions may include:
Installing a booster pump
Updating building plumbing
Balancing the supply system
Cause #10: Water Softener or Filtration System Issues
If you recently installed or adjusted a filtration system, flow restriction may occur.
JMS can adjust settings or install bypasses to improve flow.
Section 3: How to Diagnose Low Water Pressure in Your Los Angeles Home (Step-by-Step)
Before calling a plumber, try these simple checks to determine the source of your pressure issue.
Step 1: Determine if the problem is everywhere or just one fixture
One fixture = localized issue
Likely an aerator, showerhead, or single pipe clog.
Entire house = main plumbing issue
Likely the PRV, main line, leak, or aging pipes.
Step 2: Test hot vs. cold water pressure
Low cold + low hot: Main supply issue
Low hot only: Water heater issue
This instantly narrows your search.
Step 3: Check your main shutoff valve
Ensure it is completely open.
Step 4: Inspect for visible leaks
Look around:
Behind toilets
Under sinks
Near hose bibs
Around water heater
Signs of water = pressure loss.
Step 5: Clean showerheads and aerators
If pressure improves afterward, mineral buildup was the problem.
Step 6: Ask a neighbor
If they also have low pressure, it’s likely city-side.
Step 7: Check for rust-colored water
A sign of corroded galvanized pipes—common in older LA homes.
Section 4: When You Need a Professional Plumber (And When DIY Won’t Work)
Some pressure issues require a professional because the causes are underground, inside walls, or involve pressurized systems.
You need JMS Express Plumbing if:
Your home has aging galvanized pipes
Pressure has steadily dropped over time
You see signs of a slab leak
You hear banging or vibrating pipes
Hot water pressure is extremely low
Your PRV is failing
You have rusty or brown water
Your water bills are rising unexpectedly
DIY fixes help with simple issues, but major pressure loss almost always requires professional diagnosis.
Section 5: How JMS Express Plumbing Fixes Low Water Pressure Problems in Los Angeles
JMS Express Plumbing is one of the most trusted plumbing companies in Los Angeles, with decades of experience diagnosing water pressure issues in every type of home—from Beverly Hills estates to Valley Village single-family homes to LA apartments.
Here’s how we solve pressure issues quickly and permanently.
1. Whole-Home Plumbing Inspection
We test:
PSI at fixtures
City supply pressure
PRV performance
Pipe condition
Water heater function
Signs of leaks
Mineral buildup
2. Advanced Leak Detection
If a leak is suspected, we use:
Acoustic leak listening devices
Thermal imaging
Moisture detection tools
Pressure testing
This prevents unnecessary wall damage.
3. Pipe Descaling or Repiping
Depending on severity:
We remove mineral buildup
Replace clogged pipe sections
Or repipe the entire home with copper or PEX
Repiping restores full pressure instantly and increases home value.
4. PRV Replacement
If the pressure regulator is failing, we install a new one calibrated to your home’s needs.
5. Water Heater Restoration or Replacement
We flush sediment, repair valves, or recommend a new system if necessary.
6. Fixture Upgrades
Modern fixtures can improve flow, efficiency, and pressure balance.
7. Water Softener Installation
A softener prevents future buildup and keeps pressure strong long-term.
Section 6: How Much Does It Cost to Fix Low Water Pressure in Los Angeles?
Costs vary depending on the cause.
Here is a general breakdown:
Aerator cleaning: Free–$20
Showerhead replacement: $50–$200
Leak detection: $150–$400
PRV replacement: $350–$650
Pipe section replacement: $250–$800
Whole-home repipe: $4,000–$15,000 depending on size
Water heater repair: $200–$600
Water heater replacement: $1,200–$3,500
The fastest way to get an exact price is a quick visit from JMS Express Plumbing.
Section 7: How to Prevent Low Water Pressure Problems Long-Term
Here’s how LA homeowners can avoid recurring issues:
✔ Install a water softener
Prevents mineral buildup inside pipes.
✔ Flush your water heater annually
Removes sediment and restores hot water pressure.
✔ Replace old galvanized pipes
Once they begin corroding, there is no permanent fix.
✔ Schedule annual plumbing inspections
Catches small problems before they become expensive.
✔ Maintain PRV and shutoff valves
Ensure everything is operating correctly.
Section 8: Final Thoughts — Low Water Pressure Isn’t Normal, and It Can Always Be Fixed
Many Los Angeles homeowners live with low water pressure for years, thinking it’s “just how it is.” But in nearly every case, the problem is solvable—and usually easier to fix than people think.
Water pressure problems are a sign that your plumbing system needs attention. And the longer the issue goes unaddressed, the more damage may occur behind walls, under floors, or inside pipes.
Whether it’s:
Hard water buildup
A hidden leak
Aging pipes
A failing PRV
A clogged water heater
Or city-side issues
JMS Express Plumbing can diagnose and fix the issue quickly, professionally, and affordably.
Call JMS Express Plumbing Today
If your water pressure is low—or getting worse—don’t wait.
📞 Call: [Insert JMS Phone Number]
🌐 Visit: JMSExpressPlumbing.com
🚚 Fast service across Los Angeles, the Valley, Beverly Hills, Santa Monica, Glendale, Burbank, and surrounding areas
JMS Express Plumbing — Fast, Reliable, Local.
