Low Water Pressure in House? Here’s What’s Causing It (And How to Fix It)

Introduction to Low Water Pressure in a House

Low water pressure is one of those problems that sneaks up on you. One day the shower feels fine. The next, you’re rinsing shampoo like it’s 1895. If water pressure in your home has suddenly dropped—or never felt right to begin with—there’s usually a clear cause somewhere within the home’s plumbing system or water supply.

Low water pressure in a house can be caused by anything from minor fixture issues to larger system-wide problems, which is why understanding how much pressure your home should have is the first step in diagnosing the issue.

At Call Dad, we help homeowners across North and South Carolina diagnose low water pressure issues every day. Some causes are quick fixes. Others are early warning signs of bigger plumbing problems. Knowing the difference matters.

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What Is Considered Low Water Pressure?

Most homes should have water pressure between 40 and 60 PSI (pounds per square inch). Water pressure is measured in pounds per square inch, and most plumbing fixtures require at least 40 PSI to function properly.

Maintaining adequate water pressure ensures proper water flow throughout the house and allows appliances, faucets, and showers to work as intended. Pressure above or below the recommended range can cause problems over time.

Anything below 40 PSI usually feels weak—especially in showers, faucets, or when multiple fixtures are running at the same time.

Common signs of low water pressure include:

• Pressure drops when more than one faucet is on
• Appliances take longer than usual to fill
• Showers feel more like mist than steady flow

If this sounds familiar, you’re likely dealing with a real plumbing issue—not just a bad showerhead.

Common Causes of Low Water Pressure

1. Clogged or Failing Fixtures

Mineral buildup from hard water can clog faucet aerators and showerheads over time. A clogged showerhead is one of the most common causes of low water pressure in a house, especially in older homes or areas with mineral-heavy water.

As buildup worsens, it restricts water flow and can create low flow at individual fixtures even when pressure elsewhere seems normal. If low pressure is limited to one fixture—such as the kitchen sink or a single bathroom—it’s often a localized clog or failing faucet.

If multiple fixtures are affected, the problem usually runs deeper within the plumbing pipes or filtration system.

2. Partially Closed Shutoff Valves

Every home has a main house shutoff valve, typically located near the water meter or where the supply line enters the house. If this valve is not fully open, it restricts water flow throughout the entire plumbing system.

This often happens after plumbing work or maintenance. In some cases, the water meter valve near the street may also be partially closed, limiting pressure before water even enters the home.

Homes may also have a pressure reducing valve, sometimes called a pressure regulator, which controls how much pressure enters the plumbing system from the main water supply. If the pressure regulator is malfunctioning or improperly set, it can cause low water pressure throughout the house.

3. Leaks in the Plumbing System

A hidden leak pulls water away from where it’s supposed to go. Even small leaks can reduce water pressure and cause serious damage behind walls, under floors, or in crawl spaces.

Leaks can affect the entire house or only certain fixtures, depending on their location.

Signs of a plumbing leak include:

• Unexpected increases in your water bill
• Damp spots, water stains, or mold
• The sound of running water when no fixtures are on

Low water pressure combined with any of these signs is a strong reason to call a plumber.

4. Aging or Corroded Pipes

Homes built before the 1980s may still have galvanized steel pipes. These pipes corrode from the inside out, shrinking the space water can flow through and causing significant pressure loss throughout the plumbing system.

As corrosion worsens, pressure may build up behind the blockage, but water flow past it becomes weak and inconsistent. Unfortunately, cleaning won’t fix this issue—pipe replacement is usually the only long-term solution.

5. Municipal Supply Issues

Sometimes the issue isn’t inside your home. If you’re connected to city water, municipal supply problems—such as water main repairs, nearby construction, or system-wide pressure regulations—can temporarily reduce water pressure in the house.

Any disruption in the municipal water supply can impact pressure even if your internal plumbing is in good condition. If your neighbors are experiencing the same problem, it’s likely supply-related. If not, the issue is probably within your plumbing system.

Kitchen Sink Water Pressure Problems

Low water pressure at the kitchen sink is often caused by a clogged aerator or restricted supply line. Mineral buildup can reduce water flow, making everyday tasks frustrating.

Cleaning or replacing the aerator usually restores normal pressure. If the problem continues, the faucet cartridge or supply lines under the sink may be restricting water flow.

A failing pressure regulator can also contribute to low pressure at the kitchen sink and other fixtures throughout the house.

How to Diagnose Low Water Pressure

The first step is determining whether the issue affects the entire house or just one area.

A licensed plumber can:

• Measure PSI accurately
• Inspect shutoff valves and supply lines
• Check for hidden leaks
• Determine whether the issue is fixture-level or system-wide

Homeowners can attach a pressure gauge to an outdoor hose spigot or near the water meter to measure water pressure accurately and confirm whether pressure drops are occurring throughout the house.

Testing flow rate (measured in gallons per minute) helps identify low flow caused by clogs, even when pressure appears normal.

DIY guesswork often leads to unnecessary part replacements—and the problem still isn’t fixed.

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Hot Water and Pressure: Special Considerations

If you notice low water pressure affecting only the hot water, the issue is often related to the water heater or hot water supply lines.

Sediment buildup inside the water heater, a faulty pressure relief valve, clogged water softener, or corroded hot water pipes can all restrict water flow. Pressure reducing valves and pressure regulators can also impact hot water pressure if they’re malfunctioning.

In larger or multi-story homes, a booster pump may be needed to maintain consistent hot water pressure throughout the plumbing system.

Persistent hot water pressure issues should always be evaluated by a licensed plumber.

When Low Water Pressure Is an Emergency

Low water pressure requires immediate attention if:

• Pressure drops suddenly and severely
• Water becomes discolored
• You hear banging, knocking, or whistling in the pipes
• Pressure fluctuates unpredictably

These signs can point to pipe damage, failing water lines, or serious leaks.

Preventing Low Water Pressure

Routine plumbing maintenance helps keep water pressure within a healthy range. Checking for leaks, cleaning aerators, inspecting shutoff valves, and watching for corrosion all help maintain adequate water pressure.

In homes with consistently low pressure, installing a pressure tank or booster pump may be necessary to increase water pressure and maintain proper water flow throughout the plumbing system.

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How Call Dad Can Help

We don’t just turn a wrench and leave. We:

• Test water pressure accurately using a pressure gauge
• Identify the true root cause of low pressure
• Explain repair options clearly—including cost-effective solutions
• Inspect pressure regulators

If low water pressure is making daily life harder, Call Dad! We’ll get your water flowing the way it should—safely, reliably, and done right the first time.

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