When the shower trickles but the kitchen faucet runs fine, the problem sits in the shower itself: mineral scale in the showerhead, a worn cartridge, or a blocked supply line to that bathroom. When every fixture is weak, the cause is upstream, at the main valve, the pressure regulator or the street supply. Start with the showerhead. The wider fixes live under faucets, sinks, showers and disposals.
Why is my shower water pressure low?
The usual causes are scale clogging the showerhead holes, a partly closed shut-off or main valve, a worn shower cartridge, a failed pressure regulator, a leak, or old pipes. The location of the problem tells you which: one shower points to the fixture, the whole house points to the supply, and only hot water points to the water heater.
| Pattern | Most likely cause |
|---|---|
| One shower weak, others fine | Clogged head, cartridge or diverter |
| Hot weak, cold strong | Water heater, hot-side valve or scale |
| Every fixture weak | Main valve, regulator, leak or street supply |
| Weak after plumbing work | Valve left partly closed, debris in screens |
| Gradually worse over years | Corroded galvanized lines or scale |
How do I fix low pressure from a showerhead?
Unscrew the showerhead and soak it in a 50/50 mix of white vinegar and water, about an hour for light scale or overnight for heavy buildup. Rinse, scrub the nozzles with a toothbrush, clean the screen at the inlet, then reattach with fresh thread tape. This fixes a large share of weak showers.
Do it in this order:
- Take the head off the arm. Look into the inlet for a small screen and a plastic flow restrictor disk.
- Rinse the screen under the tap and soak the rest in vinegar.
- Run the shower without the head for ten seconds. If the arm flows strongly, the head was the problem.
- Reassemble and test. On hard water, expect to repeat every few months.
Hard water leaves scale. To check yours, read the water quality report your utility publishes, and see our guide to removing hard water scale. If a new head is the answer, our page on the best showerhead for low pressure water shows what to look for.
Should I remove the flow restrictor from my showerhead?
No, not as a first move. California limits showerheads to 1.8 gallons per minute, and the restrictor is how the head meets that rule. It is rarely the real cause of a weak shower. Clean the head, check the valve and supply, and if you still want more force, choose a head designed for low pressure.
The 1.8 gpm limit comes from the California Energy Commission's appliance rules (Title 20), and the building code repeats it for new work. Under Civil Code sections 1101.1 to 1101.9, older fixtures that exceed 2.5 gpm are treated as noncompliant, and a replacement has to meet current standards. EPA WaterSense labels heads at 2.0 gpm or less and requires them to keep at least 60 percent of their rated flow at 20 psi, which is why a good low-flow head can still feel strong. Check those rules for your own situation before you modify a fixture.
Could my pressure regulator or main valve be the problem?
Yes. If every fixture in the house is weak, check the main shut-off valve at the meter or where the line enters the house. It should be fully open. Then look for a pressure regulator, a bell-shaped brass device near the main line. A failing regulator can lower pressure, or let it run too high.
The California Plumbing Code is quoted by water districts as requiring a pressure regulator when static pressure goes above 80 psi, with fixtures expected to see no less than about 15 psi while running. Sources differ on the exact minimum and section numbers, so rely on a plumber for the code in force at your address. A normal home reads about 45 to 65 psi on a hardware-store gauge screwed onto a hose bib.
To check yourself:
- Screw a pressure gauge on an outside faucet. No gauge reads above 80 psi without a regulator being needed.
- Under 40 psi with the regulator in place can mean the regulator is failing, the main valve is partly closed, or street pressure is low.
- Our page on water pressure regulators explains replacement, and low water pressure in a house goes through the whole-house version.
Is low shower pressure caused by the street supply or my hillside?
It can be. Homes high on a hill can have lower pressure than homes on the flat below, and a main break or work on the street can cause a temporary drop. Ask neighbors if their pressure is also down, and if so, call LADWP and ask about pressure at your address.
A gauge reading at an outside faucet separates the cases. If the reading is low there too, the issue is on the supply side. If it is normal outside but weak in the shower, the trouble is in the house plumbing. Our page on why water pressure is low has more on this.
Do not buy a booster pump until you know the cause. A pump on a leaking or clogged line wastes money.
What if the pressure is weak only on the hot side?
If hot water is weak and cold is strong, look at the water heater. Sediment, a partly closed valve at the heater, or scaled hot-side pipes restrict flow. Check that the heater's shut-off valve is fully open. If the problem started after heater work, a debris-clogged aerator or showerhead screen is likely.
Gas and electric heaters differ in how they are serviced, and gas supply work is regulated. Do not take apart gas connections. See hot water pressure that is low and our water heater repair pages.
What does a plumber charge to fix low shower pressure?
For a worn cartridge or valve, published guides list $100 to $350 for a cartridge and $225 to $575 for a full shower valve in total. A pressure regulator or pipe replacement costs more and depends on the home. These ranges are a guide; the written quote you receive before work is the actual price.
Cheaper fixes cost almost nothing: a bottle of vinegar and an hour. The cost rises when pipes inside walls must be opened, or old galvanized lines replaced. The plumber cost page covers how quotes are put together.
When should I call a plumber about weak shower pressure?
Call if cleaning the showerhead did not help, if pressure dropped in the whole house, if the water meter moves with everything off, or if you see stains and damp spots. We'll arrange a local plumber to come to you with a written quote before work starts. Ask on our quote page.
Other reasons to call:
- Rusty or brown water along with weak pressure, which suggests corroded pipes.
- A hissing or banging sound at the regulator.
- A gauge that reads over 80 psi.
Take a look at our home page and plumber for low water pressure page for the full set of options.
Common questions
How long does it take to fix low shower pressure?
Cleaning a showerhead takes under an hour including soak time. A plumber replacing a cartridge usually needs an hour or two, and a pressure regulator swap is often a few hours. A repipe of old pipes takes days. A plumber can tell you which one applies once they test the pressure at your home.
What should I ask before I hire a plumber for low pressure?
Ask the plumber to measure static pressure with a gauge before quoting, how they will find the cause, what the written quote includes, and whether a permit applies in the City of Los Angeles. Ask what they will replace and why. We'll arrange a visit and a quote through our quote page.
Does someone need to be at the property?
Usually yes, at least for the start and the finish, so the plumber can reach the shower and the main valve and explain the cause. They may need access to a garage, a meter box or a yard. If you cannot be there, say so when you ask for the visit.
Is it legal to remove my showerhead's flow restrictor in California?
California sets a 1.8 gpm maximum for showerheads sold and installed, and the restrictor is part of how a head meets it. Removing it can put the head out of compliance, so most plumbers and guides advise against it. Try cleaning the head, checking the supply, or fitting a head made for low pressure.
Can high pressure cause low shower flow?
Not directly, but a failed regulator can lead to either extreme. Above 80 psi, fittings and valves wear and leak, and cartridges clog sooner. A plumber measures static pressure at a hose bib. If it reads above 80 psi, the regulator needs attention. See water pressure regulators.