Why Is My Water Pressure Suddenly Low in One Faucet?

January 19, 2026 in plumbing

Why Is My Water Pressure Suddenly Low in One Faucet?

What causes sudden loss of water pressure in a house

If you’ve suddenly noticed low water pressure in just one faucet, it could be due to a clogged aerator, a faulty cartridge, or a localized pipe issue. These are all common culprits behind isolated pressure drops. When you’re wondering what causes sudden loss of water pressure in a house, keep in mind that while system-wide issues like main line leaks affect the entire home, problems in just one fixture usually point to something right at that faucet. For example, mineral buildup in the aerator can restrict water flow, or a worn-out valve inside the faucet might be limiting pressure. Identifying the source quickly can help you avoid unnecessary frustration.

Common Household Causes Behind Loss of Water Pressure

When diagnosing what causes sudden loss of water pressure in a house, it’s important to first determine if the issue is isolated or system-wide. If it’s affecting your entire home, you’re looking at broader issues like main line leaks or pressure regulator malfunctions. Let’s dive into the most common culprits and how to approach each one.

1. Clogged Pipes or Fixtures

Mineral buildup from hard water can restrict water flow in your home’s plumbing over time. This is particularly common in older homes with galvanized pipes that are more prone to corrosion.

  • Aerator Blockage: Faucet aerators can trap mineral fragments, resulting in a noticeable pressure drop in just one fixture.
  • Showerheads: Similar buildup in showerheads can affect water flow, creating a weak stream.
  • Internal Faucet Cartridges: Worn or blocked cartridges inside the faucet body can restrict pressure.

2. Malfunctioning Pressure Regulator

A pressure regulator controls the water pressure entering your home. If it fails, you may experience a sharp drop—or spike—in pressure.

  • Symptoms: Low water pressure throughout the house, including showers, toilets, and sinks.
  • Consider professional inspection and replacement of water pressure regulators if fault is suspected.

3. Slab or Hidden Leaks

Another common cause of sudden pressure loss in homes is a hidden leak—especially a slab leak in homes with foundations built on concrete. These can cause water to escape underground before it reaches fixtures.

  • Tell-tale signs: Unexplained water on floors, warm spots, or mold growth.
  • These issues require immediate attention through slab leak detection and repair services.

4. Municipal Supply Issues

Sometimes, external factors cause water pressure to drop. If your neighbors are experiencing similar problems, your city’s water supply could be facing a temporary disruption or maintenance.

  • Check: Contact your local water utility company to confirm whether there are known outages or pressure adjustments.

5. Partially Closed or Faulty Valves

Sudden changes in pressure could result from valves that aren’t fully open, either intentionally or due to corrosion or mechanical failure.

  • Main Shut-Off Valve: If partially closed, it can restrict the entire home’s water flow.
  • Water Meter Valve: Located near the street or curb, if this valve is tampered with or left partially closed, it can impair pressure.

6. Old or Corroded Pipes

If your plumbing system is older, corroded steel or copper pipes may be affecting flow. Rust and sediment build up over time, closing in pipe interiors and reducing pressure output.

  • Visible Indicators: Dirty or discolored water during initial flow, deterioration signs around pipe joints.
  • Consider a full or partial repipe using modern materials like PEX or copper to resolve this long-term.

How to Diagnose the Water Pressure Problem

To pinpoint what causes sudden loss of water pressure in a house, follow this step-by-step guide:

  1. Check One or Multiple Fixtures: Determine whether the issue is isolated to a single faucet or present home-wide.
  2. Clean Aerators/Showerheads: Unscrew and clean screens from kitchen faucets or showerheads to remove mineral debris.
  3. Inspect Valves: Ensure both main and individual fixture valves are fully open.
  4. Ask Neighbors: See if nearby homes are experiencing the same problem—this could point to a municipal issue.
  5. Measure Pressure: Use a water pressure gauge on an exterior faucet. Standard range is 40–60 psi; anything well below may indicate a problem.

Professional Services That Can Help

Sometimes, DIY checks are not enough to determine what causes sudden loss of water pressure in a house. In such cases, you may need professional services such as:

  • Hydrojet Plumbing: Clears deep blockages in your home’s drain lines using high-pressure water jets.
  • Sewer Camera Inspection: Identifies obstructions, cracks, or root intrusions in plumbing lines.
  • Leak Detection: Advanced methods like infrared or acoustic technology find hidden and slab leaks.
  • General Plumbing Repairs: Fixes everything from faulty valves to cleaning mineral deposits within your fixtures.

Table of Pressure Problems and Solutions

Issue Symptoms Suggested Action
Clogged Aerator Low pressure at one faucet Remove and clean the aerator
Faulty Pressure Regulator Inconsistent or low pressure in entire home Replace regulator
Slab Leak Wet floors, drop in pressure Call for slab leak detection
Municipal Supply Issue Shared neighbor issue Contact city water department
Old Corroded Pipes Low pressure and rusty water Repipe plumbing system

Expert Help When You Need It

Understanding what causes sudden loss of water pressure in a house is the first step toward restoring full functionality to your home. Whether it’s a minor blockage or a serious underground leak, swift action can prevent long-term damage and inconvenience. If cleaning fixtures or inspecting valves doesn’t do the trick, calling in a licensed plumber may cost you upfront—but it will save you in the long run by fixing the root issue.

Whether you’re dealing with a mystery blockage, faulty valve, or poor water flow in just one room or throughout the house, don’t overlook the potential need for a plumbing repipe as part of your pressure restoration plan.

Don’t Let Water Pressure Problems Drain You

When you’re asking what causes sudden loss of water pressure in a house, it’s often a sign of an underlying issue that needs urgent attention. By identifying whether the problem is localized or affects the whole household, you can decide on the next best steps—whether DIY fixes, simple inspections, or calling a pro to investigate hidden leaks or replace aging pipes. Restoring water pressure is not just about convenience, but also about health, hygiene, and functionality. Take the signs seriously and don’t hesitate to bring in professional help when needed.

Frequently Asked Questions

What causes a sudden drop in water pressure in the whole house?
A sudden drop in water pressure throughout the entire house can be caused by a failing pressure regulator, a partially closed main water valve, municipal supply issues, or even a hidden leak such as a slab leak under your foundation. These issues often require professional diagnosis and repair.
Why is there low water pressure in only one faucet?
Low water pressure isolated to a single faucet is usually due to a clogged aerator, a blocked or worn-out cartridge, or debris in the supply lines connected to that fixture. Cleaning or replacing these components often restores normal pressure.
How do you fix sudden low water pressure?
To fix sudden low water pressure, start by checking if all fixtures are affected. Clean faucet aerators and showerheads, ensure all valves are fully open, and use a pressure gauge to check PSI. If the problem persists, professional services such as leak detection or regulator replacement may be required.
Can a water leak cause low water pressure?
Yes, a hidden water leak can significantly reduce water pressure in your home. Leaks, especially slab leaks under the foundation, divert water away from your plumbing system before it reaches your fixtures, causing noticeable drops in pressure.
How can I test my home’s water pressure?
You can test your home’s water pressure using a pressure gauge attached to an outdoor faucet. Normal residential pressure typically ranges between 40–60 psi. Readings below this may indicate a problem such as a faulty regulator or blockage in your system.

Say Goodbye to Sudden Drops in Water Pressure — Here’s Your Next Step

Tired of inconsistent water flow or sudden pressure issues that interrupt your day? Whether you’re dealing with a blocked aerator, aging pipes, or mysterious leaks, getting to the root of the problem is essential. At HomePro Plumbing and Drains, we specialize in diagnosing and fixing water pressure problems fast—so you don’t have to guess, stress, or deal with dripping disappointment. Ready to bring back steady flow and total peace of mind?

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