Water pressure problems fall into two very different categories: pressure that's too low, which is more common, and pressure that's too high, which causes its own kind of damage over time. Both are worth understanding before assuming the worst.
What Normal Pressure Looks Like
Most homes run comfortably between 40 and 60 psi. Anything above 80 psi puts unnecessary stress on fixtures, water heaters, and pipe joints. A simple pressure gauge that screws onto an outdoor spigot, available at most hardware stores, gives you a quick baseline reading.
Common Causes of Low Pressure
- Hard water scale buildup: Stillwater's water hardness, around 8.5 grains per gallon, gradually narrows pipe diameter from the inside, especially in older galvanized lines.
- A partially closed shutoff valve: Worth checking at the main valve and at the water heater if pressure dropped suddenly.
- A failing pressure-reducing valve: If your home has one, it can fail in a way that restricts flow rather than just regulating it.
- A leak somewhere in the system: Pressure that's dropped gradually over weeks or months, without any of the above explanations, is worth ruling out with a pressure test.
Common Causes of High Pressure
High municipal supply pressure, combined with a failed or missing pressure-reducing valve, is the usual cause. Consistently high pressure shortens the life of water heaters, washing machine hoses, and pipe joints, and it's a common contributor to fixture leaks that seem to appear for no reason.
When Low Pressure Actually Means a Leak
A gradual, unexplained drop across the whole house, not just one fixture, is the pattern worth paying attention to. If a pressure test shows the system isn't holding steady, that points to an active leak rather than scale or a valve issue, and it's worth tracing before it gets worse.
What You Can Check Yourself
Start with a single fixture: if only one faucet has low pressure, the aerator on that fixture is often just clogged with mineral deposits and can be cleaned or replaced cheaply. If every fixture in the house is affected at once, the cause is upstream, at the main line, a valve, or in the pressure itself, and worth a professional look.