Why Did My Water Pressure Suddenly Drop in My House?

A sudden drop in water pressure can be frustrating and alarming. One moment, everything works fine, and the next, your shower barely flows.

In Phoenix homes, water pressure problems can be caused by plumbing issues, mineral buildup, or problems with the city water supply. Understanding the cause helps you avoid bigger plumbing damage and costly repairs.

Common Reasons Water Pressure Drops Suddenly

Hidden Plumbing Leaks

A hidden leak is one of the most serious causes of sudden water pressure loss. When water escapes before reaching your fixtures, pressure drops throughout the home.

Warning signs include:

• Higher water bills

• Damp walls or floors

• Mold or mildew smells

Leaks under slabs are especially common in Phoenix due to shifting soil and aging pipes.

Mineral Buildup From Hard Water

Phoenix is known for hard water. Over time, mineral deposits build up inside pipes, narrowing the passage for water.

This buildup can cause:

• Gradual or sudden pressure loss

• Uneven pressure between fixtures

• Reduced water flow in older homes

Partially Closed Main Water Valve

Sometimes the issue is simple. If your main shutoff valve isn’t fully open, water pressure will drop instantly.

This often happens after:

• Plumbing repairs

• Meter checks

• Home renovations

Faulty Pressure Regulator

Homes with pressure-reducing valves rely on them to control incoming water pressure. When the regulator fails, pressure can suddenly drop or fluctuate.

Signs of a failing regulator include:

• Pressure changes throughout the day

• Weak flow at multiple fixtures

• Sudden pressure loss without leaks

Clogged Pipes or Fixtures

Sediment, rust, and debris can clog pipes or fixture aerators. While this usually starts slowly, a blockage can worsen suddenly and cause a noticeable drop in pressure.

City Water Supply Issues

Sometimes the problem isn’t inside your home. City water maintenance, broken mains, or pressure adjustments can temporarily affect water flow.

If neighbors are experiencing the same issue, the cause is likely municipal.

How to Troubleshoot a Sudden Pressure Drop

Check Multiple Fixtures

If pressure is low everywhere, the issue is likely with your main line, pressure regulator, or supply.

If it’s only one fixture, the problem may be localized.

Inspect Valves and Shutoffs

Ensure all shutoff valves are fully open, including the main valve and individual fixture valves.

Remove and Clean Aerators

Unscrew faucet aerators and remove sediment buildup that may restrict flow.

When to Call a Professional Plumber

Call a plumber if:

• Pressure drops suddenly and doesn’t return

• You suspect a hidden or slab leak

• Water pressure fluctuates daily

• Multiple fixtures are affected

Delaying repairs can lead to pipe damage, water waste, and costly repairs.

Why Water Pressure Problems Are Common in Phoenix Homes

Phoenix plumbing systems face unique challenges, including:

• Hard water mineral buildup

• Aging pipes in older neighborhoods

• Expansive soil affecting underground lines

• Extreme heat stresses plumbing materials

Professional inspection ensures the issue is diagnosed correctly the first time.

Call Vertical Plumbing at (480) 577-8720