Water Pressure Problems: What's Causing It and What to Do
Weak water pressure turning your shower into a trickle is frustrating enough. But water pressure problems go beyond inconvenience — they can signal plumbing issues that are worth understanding before they become more serious. Whether your pressure is too low, too high, or inconsistent, there's usually a diagnosable cause and a clear solution.
Low Pressure in Just One Fixture vs. Throughout the Home
The first useful question is where the low pressure is occurring. If it's limited to one faucet or showerhead, a clogged aerator or showerhead is the most likely cause. Mineral buildup from hard water narrows the small openings in these fixtures over time. Soaking the aerator in white vinegar overnight usually restores flow — and if not, replacement is inexpensive.
If the pressure is low throughout the entire home, the cause is somewhere in the supply system. That's a different category of problem and worth investigating more carefully.
Whole-Home Low Pressure: What to Check
Several things can cause low pressure throughout a home:
- Partially closed shutoff valve: Check the main shutoff valve where the water line enters your home. If it's not fully open, it restricts flow to every fixture.
- Pressure reducing valve (PRV): Most homes on municipal water have a PRV that regulates supply pressure. A failing PRV can cause pressure to drop significantly and usually needs replacement.
- Pipe corrosion or scale: In older homes with galvanized steel pipes, internal corrosion narrows the pipe interior over time. This causes progressively worsening pressure throughout the home.
- Supply leak: A leak somewhere in the supply line diverts water pressure. According to EPA WaterSense water use facts, household leaks waste enormous amounts of water annually — and a significant leak can noticeably reduce pressure.
Don't Overlook High Pressure
High water pressure gets less attention, but it causes real damage over time. Municipal supply pressure can run higher than household plumbing is designed to handle. Symptoms include banging pipes (water hammer), water running faster than needed from fixtures, and appliance connections that fail more quickly than they should. A pressure gauge that screws onto a hose bib lets you measure your supply pressure — anything consistently above 80 PSI warrants a PRV inspection or installation.
When to Call a Plumber
If the simple checks don't identify the cause, or if you suspect a leak or need pipe work, professional diagnosis saves time and prevents guesswork from becoming expensive. We provide plumbing service in St. Peters and throughout the surrounding communities. Our full range of professional plumbing services covers St. Charles, St. Louis, Lincoln and Warren Counties.
Call (636) 397-3200 for a water pressure assessment, or schedule online at aaastl.com. Our technicians do not work on commission — you'll get an accurate diagnosis and straightforward options.
