Homeowner guide
Why your water pressure is low
The first useful question is whether it is one fixture or the whole house. In Florissant that distinction separates a five-minute fix from a conversation about sixty-year-old galvanized pipe.
- One fixture vs. the whole house
- What you can fix yourself
- When it means the pipe itself
- Why age matters here
The short version
Start here
Work down the list. Most situations are answered in the first two rows.
One fixture only
Almost always a clogged aerator or a worn cartridge. Unscrew the aerator and rinse it before anything else.
Usually easy
One bathroom
Often a partially closed shutoff, a failing shower cartridge, or a scaled branch line serving that part of the house.
Localized
Whole house, sudden
A failed pressure regulator, a partially closed main valve, or a problem on the utility side. Ask a neighbor.
Check first
Whole house, gradually worse
Galvanized supply scaling inward over decades. Common in original Florissant homes, and it does not reverse.
The pipe
Whole house, with a high bill
Losing pressure and gaining bill at the same time usually means water is escaping between the meter and your fixtures.
Suspect a leak
General guidance for Florissant-area homes. Every house is different — call if you are unsure.
Detail
The causes, in the order we check them
Clogged aerators
The screen at the tip of the faucet. Rinsing one solves a surprising number of calls, and it costs nothing to try.
Worn cartridges
Inside the faucet or shower valve. They wear out, and the symptom is reduced or uneven flow at that fixture only.
Pressure regulator failure
Most homes have one where the service line enters. When it fails it usually fails low, and the whole house drops at once.
Partially closed valves
A main shutoff or meter valve not fully open. It sounds too simple to be the answer, and sometimes it is the answer.
Galvanized scaling
Original steel supply pipe rusting inward. Gradual, whole-house, worse every year, and permanent short of a repipe.
A hidden leak
Water leaving the system before it reaches your tap. Look for a jump in the bill or a green patch in the yard.
The honest answer
When it means repiping
Nobody wants this answer, so here is the specific evidence that points to it.
If pressure has declined gradually over years rather than dropping suddenly, affects the whole house rather than one fixture, and the home still has original galvanized supply, the pipe is the problem. Galvanized scales inward from the day it is installed, and in a house built in 1963 the interior diameter can be a fraction of what it started as. Cleaning fixtures will not help and replacing the regulator will not help. If you are also seeing rusty water at first draw or repeat pinhole leaks, that confirms it. The one piece of good news: a partial repipe of the trunk line sometimes solves most of the pressure problem for meaningfully less than a whole-house job.
Common questions
What homeowners ask us
Why is my water pressure low in only one faucet?
Almost always a clogged aerator or a worn cartridge. Unscrew the aerator and rinse the screen — that fixes it more often than not.
Why did my whole house lose pressure suddenly?
Most often a failed pressure regulator or a partially closed main valve. Check with a neighbor to rule out a utility-side issue first.
Can low pressure mean a leak?
Yes. If pressure is down and the water bill is up, water is likely escaping before it reaches your fixtures. A meter test will confirm it.
Does old galvanized pipe cause low pressure?
Yes, and it is the most common cause of gradual whole-house pressure loss in Florissant's original housing. Corrosion narrows the pipe from the inside.
Will a new water heater fix low hot water pressure?
Only if the heater is the problem. Low pressure on the hot side alone often points to sediment in the tank or a scaled outlet, which is worth checking first.
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Related: galvanized pipe replacement, galvanized pipe explained, leak detection, faucet installation, signs you need a plumber
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