Low water pressure is frustrating, but the cause is often something simple and local rather than a whole-house problem. Start by figuring out whether it affects one fixture or the entire house.
One fixture only
If only one tap or shower is weak, the fix is usually a clogged aerator or showerhead. Unscrew it, clear the mineral debris or soak it in vinegar, and reinstall. A partially closed shutoff valve under a sink can also be the culprit.
Whole house
If pressure is low everywhere, check that the main shutoff is fully open. Homes with a pressure-reducing valve can lose pressure if that valve fails — it can be adjusted or replaced. Old galvanized pipes that have corroded internally also restrict flow.
When to call a plumber
Sudden whole-house pressure loss, especially with discoloured water, can mean a leak, a failing regulator, or a municipal issue. A plumber can measure pressure and pinpoint the cause.