If water pressure is low everywhere in the house, the cause is almost always one of three things: the pressure-reducing valve near the main has failed, the main shutoff valve is not fully open, or the house has old galvanized steel pipes that have closed up with rust. Call (201) 676-3099 or book a free estimate.
If water pressure is low everywhere in the house, the cause is almost always one of three things: the pressure-reducing valve near the main has failed, the main shutoff valve is not fully open, or the house has old galvanized steel pipes that have closed up with rust. If pressure is low at one faucet or one shower only, it is a clogged aerator, cartridge or showerhead, which is a $0 to $250 fix.
Here is how to tell which one you have before you call anyone.
First, figure out where it is low
Unscrew the aerator on the faucet or the showerhead and run the water. If it is strong without it, soak the part in vinegar or replace it. Still weak? The cartridge inside the faucet or shower valve is clogged. $150 to $350 to replace.
The problem is at the water heater: a partly closed valve on top, sediment in the tank, or a failing dip tube. Tankless units clog with scale. $150 to $500 for most fixes; a tank full of sediment on a 10-year-old heater is a replacement conversation.
Check the main shutoff valve is fully open (turn it counterclockwise until it stops). Then find the bell-shaped pressure-reducing valve near where water enters the house. If the house was built before 1970 and has gray steel pipes, read the galvanized section below.
Usually the town supply during peak hours, a neighbor's irrigation on a shared line, or a regulator that is starting to fail. A $15 pressure gauge on an outside spigot, checked morning and evening, tells the story.
The 8 causes, and what each fix costs (NJ, 2026)
| Cause | How you know | Typical fix |
|---|---|---|
| Clogged aerator or showerhead | One fixture, strong without the aerator | $0 – $60 (clean or replace) |
| Clogged faucet or shower cartridge | One fixture, still weak without the aerator | $150 – $350 |
| Main shutoff or meter valve not fully open | Whole house, often after recent plumbing work | $0 – $150 |
| Failed pressure-reducing valve (PRV) | Whole house, gauge reads under 40 psi, valve is 10+ years old | $350 – $900 replaced |
| Water heater sediment or bad dip tube | Hot side only | $150 – $500; replace if the tank is old |
| Galvanized steel pipes rusted shut inside | House built before 1970, brown water, pressure got worse over years | Repipe: $6K – $18K, or a partial repipe of the worst runs |
| Leak underground on the service line | Whole house, water bill went up, wet spot in the yard | $350 – $3K to find and fix; new service line $3K – $8K |
| Town pressure or a shared supply problem | Neighbors have it too | Booster pump $1,200 – $3,000 if the town cannot fix it |
The pressure-reducing valve: the usual suspect
Most New Jersey homes on town water have a brass, bell-shaped pressure-reducing valve near the main shutoff. It knocks street pressure of 80 to 150 psi down to a safe 50 to 60 psi. They last 10 to 15 years, then either creep low (weak showers) or fail high (banging pipes, a water heater relief valve that drips, faucets that spit). Replacing it is a two-hour job, $350 to $900, and it is the fix in more than half the whole-house pressure calls we get.
Galvanized pipes: why the pressure kept getting worse
Galvanized steel pipe rusts from the inside. A 3/4-inch pipe from 1955 can have a 1/4-inch hole left down the middle by now. The signs: pressure that faded slowly over years, brown water after a vacation, gray threaded pipes in the basement, and the hot side weaker than the cold. Cleaning does not work. The fix is replacing the steel with PEX or copper, usually $6,000 to $18,000 for a whole house, and it can often be done in two to four days without opening every wall. Do the worst runs first if the budget is tight.
Do this before you call
- Screw a $15 pressure gauge onto an outside spigot or the washing machine valve. Under 40 psi is low. Over 80 psi is too high and needs a regulator.
- Turn the main valve fully open. Somebody may have half-closed it during a repair.
- Run hot only, then cold only, at one faucet. Which side is weak tells you a lot.
- Ask a neighbor. If they have it too, call the water utility first.
How we find it
We put a gauge on the system, check the regulator, pull an aerator, and look at the pipe material, in that order. Most calls end with a clear cause and a written price in under 30 minutes. If it is a repipe, you get an itemized price for the whole house and a smaller price for just the worst runs, and you decide.
Questions people ask next
What is normal water pressure for a house?
50 to 60 psi is ideal. Under 40 psi feels weak; over 80 psi is too high and shortens the life of every fixture and the water heater. A $15 gauge on an outside spigot tells you in ten seconds.
Why is my water pressure low all of a sudden?
A sudden drop everywhere is usually a failed pressure-reducing valve, a valve that got partly closed, or a leak on the service line. A sudden drop at one fixture is a clogged aerator or cartridge, often right after work on the water main stirred up sediment.
How much does it cost to fix low water pressure?
Anywhere from free (opening a valve, cleaning an aerator) to $350–$900 for a new pressure regulator. Old galvanized pipes are the expensive case: $6,000 to $18,000 to repipe the house.
Can a water softener or filter cause low pressure?
Yes. A clogged sediment filter or an old softener bed restricts flow for the whole house. Change the filter, or bypass the softener for a minute and see if the pressure comes back.
Will a booster pump fix my water pressure?
Only if the supply pressure into the house is truly low and the pipes are clear. A booster on clogged galvanized pipes does nothing. Rule out the regulator and the pipes first.
Need a plumber near you?
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Tired of the weak shower?
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Or call Alex direct: (201) 676-3099