Start With the Pressure Regulator
City water typically arrives at your property somewhere around 70–90 psi. A pressure regulator (a brass, often bell-shaped device where the main line enters your house) brings that down to a safer level for household plumbing, usually around 50–60 psi. If your regulator is failing, water pressure throughout the house can drop noticeably — and this is one of the most common causes of low pressure that has nothing to do with a leak at all.
A plumber can test your actual pressure with a gauge at an outdoor hose bib in a few minutes. If it reads unusually low, the regulator (or a closed/partially closed main valve) is a more likely culprit than a leak.
When Low Pressure Points to a Leak
If the pressure at the hose bib tests normal but you’re still noticing weak flow at specific fixtures, or if the pressure has dropped gradually alongside other signs like a rising water bill, a leak becomes more likely. A significant leak diverts water that would otherwise reach your fixtures at full pressure — especially true for underground water line leaks or a slab leak on a main branch line.
- Regulator or valve issue: pressure is low everywhere, tests low at the hose bib, no other symptoms
- Mineral buildup in old pipes: gradual decline over months or years, common in original 1950s–60s galvanized lines
- Leak somewhere in the system: pressure drop paired with a rising bill, a warm spot, or a soggy patch of yard
- Fixture-specific issue: only one faucet or shower is weak — usually a clogged aerator or showerhead, not a plumbing-wide problem
Not Sure If It’s a Leak?
We’ll test your actual pressure and rule out (or confirm) a leak in minutes.
Low Water Pressure: Common Causes
Sometimes it’s a simple fix. Sometimes it’s a sign of a leak. Here’s how to tell which.