Low water pressure usually comes from one of five things: a clogged aerator or shower head, a dirty whole-house filter, old galvanized pipe that has rusted closed inside, a well pressure tank or pressure switch problem, or a failing pressure reducing valve on town water. The fastest way to narrow it down is to see whether the problem is at one faucet or the whole house, and whether it is hot, cold or both.
Step one: one fixture or the whole house?
Turn on the cold water at a few sinks and a tub on different floors. Then try the hot.
- Only one faucet or shower is weak: the problem is almost always at that fixture.
- Only the hot water is weak: look at the water heater, its shutoff valve or scale in the hot lines.
- Everything is weak: the cause is near where water enters the house. That means the well system, a filter, the main shutoff, a pressure reducing valve or the pipes themselves.
Common causes and what you can check
Clogged aerators and shower heads
Unscrew the aerator at the tip of the faucet and look for grit or white scale. Rinse it or soak it in white vinegar. Do the same with the shower head. This is the most common fix and it costs nothing.
A dirty whole-house filter
Many well homes have a sediment filter near the pressure tank. When the cartridge fills up, pressure drops through the whole house. If the housing is clear, you may see that it is brown. Shut the valves on both sides, press the relief button if it has one, and change the cartridge following the maker's steps. If you are not sure which valves to close, call us.
Old galvanized steel pipe
Galvanized pipe was common in older homes. Over decades, rust and scale build up inside it and close the opening, a bit like a clogged artery. The USGS notes that scale inside pipes can cut water flow and lower pressure. Hard water makes it worse. Signs include pressure that got worse slowly over years, rusty water after the water sits, and gray threaded pipe in the basement. There is no fix for pipe that is closing up inside except replacing it. Our PEX repiping page explains how that works.
Well pressure tank or pressure switch
On a well, a pump pushes water into a pressure tank. A pressure switch turns the pump on when pressure drops and off when it reaches the top setting. Common settings are 30/50 or 40/60, meaning on at 30 and off at 50, or on at 40 and off at 60. Watch the gauge near the tank while someone runs water:
- If the pressure drops and the pump kicks on at the low number and climbs back up, the system is working. The low feeling may just be the bottom of the cycle.
- If the pump turns on and off every few seconds, the tank may have lost its air charge or its bladder may have failed. This is called short cycling, and it wears out the pump.
- If the pressure never climbs back up, the problem could be the switch, the pump or the well itself.
Do not open the pressure switch cover. It has live electrical parts inside. Checking and replacing tanks and switches is work we do inside the house. See our well tanks and well water page. Problems down in the well itself go to a licensed well driller.
Pressure reducing valve on town water
Homes on town water often have a pressure reducing valve, or PRV, near the main shutoff. It is usually a bell-shaped brass valve. When one fails, pressure can drop too low or climb too high. A licensed plumber can test your pressure with a gauge and replace the valve if needed.
A partly closed valve
After any plumbing work, check that the main shutoff and the water heater valve are fully open. It sounds simple, but we find it more than you would think.
A hidden leak
A leak in the line can lower pressure. On a well, a pump that runs when no one is using water is a clue. On town water, watch the meter for an hour with everything off. The EPA's WaterSense program says household leaks can waste thousands of gallons of water a year in a typical home, so it is worth looking.
When to call a licensed plumber
- Pressure is low through the whole house and the filter and valves check out.
- Your well pump short cycles or runs when no water is on.
- You have galvanized pipe and rusty or weak water.
- You see water on the floor, hear water running inside walls, or your meter moves with everything off. Our low water pressure page covers more.
Why this happens around Budd Lake and Morris County
Our area mixes town water and private wells, so the cause of low pressure changes from street to street. In Flanders, Budd Lake and parts of Roxbury with town water, we often look at PRVs and old pipe. In Long Valley, Chester, Byram and outer parts of Mount Olive, most homes are on wells, and the pressure tank, switch and filters are the first places we look. Hard well water adds scale to fixtures and pipes over time. Older homes around Netcong, Wharton and Mine Hill still have some galvanized pipe hidden in walls.
Frequently Asked Questions
What is normal water pressure in a house?
It varies. On a well, pressure moves between the switch settings, often 30 to 50 or 40 to 60 psi. On town water, a plumber can test your pressure with a gauge and tell you if it is in a healthy range for your home.
Why is only my hot water pressure low?
The cause is usually at the water heater, like a partly closed valve, sediment in the tank or scale in the hot water lines. It can also be a failing mixing valve in a single shower.
Can a water softener lower my pressure?
A softener that is undersized, clogged or set up wrong can reduce flow. A properly sized unit should not cause a big drop.
Can I adjust my well pressure switch myself?
We do not recommend it. The switch has live electrical parts, and the tank air charge has to match the settings. Call a licensed plumber.
If you want a second set of eyes on it, call or text us at 862-362-0634 or request service online. We are a family owned shop in Budd Lake, and we will tell you straight what we find and what it needs.
Sources
Micky Cipolla is a New Jersey licensed master plumber (License #13478) with more than 15 years in plumbing and heating. He owns Tucker's Plumbing in Budd Lake and works on homes across Morris County every day. Verify the license.