Low Water Pressure
Why Is My Water Pressure Low? Common Causes & Fixes for Phoenix Valley Homeowners
If you've noticed your shower feels more like a drizzle or your kitchen faucet takes forever to fill a pot, you're dealing with one of the most frustrating plumbing problems a homeowner can face: low water pressure. In the Phoenix Valley, low water pressure is a common complaint — and it has more causes than most people realize. This guide will walk you through the most likely culprits and what you can do about them.
What Is Considered Normal Water Pressure?
Most homes operate comfortably at 40–80 PSI (pounds per square inch). Anything below 40 PSI is generally considered low, and you'll likely notice it in your daily routines. Pressure above 80 PSI can actually damage pipes and appliances, so balance matters on both ends.
Common Causes of Low Water Pressure in Phoenix Homes
Hard water mineral buildup: Phoenix has some of the hardest water in the country. Over time, calcium and magnesium deposits accumulate inside pipes, faucet aerators, and showerheads — restricting flow significantly.
Corroded or aging pipes: Older homes with galvanized steel pipes are especially prone to internal corrosion. As rust builds up inside, the effective pipe diameter shrinks, reducing pressure.
A partially closed shutoff valve: If someone recently worked on your plumbing or your meter was serviced, a shutoff valve may have been left partially closed. Check both the main shutoff and the meter shutoff.
Pressure regulator failure: Many Phoenix Valley homes have a pressure reducing valve (PRV) installed to protect plumbing from high municipal pressure. When these fail, pressure can drop dramatically.
Slab leak or supply line leak: A hidden leak in your supply system diverts water before it reaches your fixtures — and your pressure suffers for it.
Municipal supply issues: Occasionally, the city water supply itself is the problem. Check with your neighbors to see if they are experiencing the same thing.
If you suspect that you have a leak, take a look at our Leak Detection & Repair and Slab Leak pages.
How to Diagnose the Problem
Start simple. Check if the low pressure is isolated to one fixture or affects the whole house. A single low-pressure faucet often just needs a cleaned aerator. Whole-house low pressure points to the supply system, PRV, or main line. If your pressure has gradually declined over months, mineral buildup or pipe corrosion is likely. Sudden drops suggest a leak or a valve issue.
Hard Water and Your Pipes
Phoenix sits in one of the hardest water regions in the entire United States. The Salt River Project and other municipal sources pull heavily mineralized water from the Colorado River. Over years of use, that mineral content coats the inside of your pipes, fixtures, and appliances. If low pressure is being caused by scale buildup, a whole-home water softener or filtration system can make a dramatic difference — both for your water pressure and the longevity of your plumbing.
If you need a new water softener or water treatment system, look at out Water Treatment page for more information.
When to Call a Plumber
If you've cleaned your aerators, confirmed your shutoff valves are fully open, and ruled out a city-side issue — it's time to call a professional. A licensed plumber can test your home's pressure at multiple points, inspect your PRV, check for hidden leaks, and assess the condition of your supply lines. At Mountain Vista Plumbing, we give you an honest diagnosis and transparent options so you can make the right call for your home and your budget.
Call Mountain Vista Plumbing today at 480-847-9769 or visit mountainvistaplumbing.com/contact to schedule your service.
