Low Water Pressure in Your GTA Home? Here Are the 7 Most Common Causes

A trickle where you expect a strong flow is one of the most common complaints plumbers hear. The good news: low water pressure usually has a clear cause. The bad news: some of those causes are serious.

Here are the seven most common culprits — in order from easiest to hardest to fix.

1. Clogged Aerator or Showerhead

If the pressure is only low at one fixture, start with the simplest explanation. The aerator (the small mesh screen at the tip of the faucet) traps mineral deposits over time. Unscrew it, clean it with white vinegar, and reinstall it. Same goes for showerheads.

2. Partially Closed Shutoff Valve

If someone recently did work on your plumbing, check that the shutoff valve (at the fixture, or the main valve) was fully reopened. A gate valve that is even slightly closed can cut pressure significantly.

3. Pressure Reducing Valve (PRV) Failing

Most GTA homes have a PRV where the water line enters the house. It is designed to reduce municipal supply pressure (which can be very high) to a safe range for household plumbing — typically 45–80 psi. When a PRV fails or is set too low, pressure drops throughout the house. PRV replacement is a straightforward plumbing job.

4. Failing Pressure Tank (for Well Systems)

Homes in rural areas outside the GTA on well water use a pressure tank. When the bladder inside the tank fails, pressure fluctuates wildly or stays low. A plumber can test the tank charge and replace it if needed.

5. Corroded or Scaled Pipes

In GTA homes built before 1980, galvanized steel pipes are common. Over decades, the interior of these pipes corrodes and the passage narrows with rust and scale deposits — sometimes down to a fraction of the original diameter. Pressure drops, flow becomes weak, and water may appear rusty. The fix is repiping — replacing the old galvanized lines with copper or PEX.

6. Hidden Leak in the System

A significant leak somewhere in your plumbing — behind a wall, under the slab, or in the yard — bleeds off pressure before it reaches your fixtures. Signs include an unexplained jump in your water bill, damp spots on walls or ceilings, or the sound of running water when everything is off. This requires professional leak detection.

7. Municipal Supply Issue

Sometimes it is not your plumbing at all. Check with your neighbours. If they have the same issue, the problem is upstream at the city main. Contact Toronto Water or your local utility to report it.

How to Confirm It Is Not a Leak

Turn off all water in the house and check your water meter. If the dial is still moving, you have a leak somewhere. Call a plumber for leak detection before the problem gets worse.

We diagnose and fix low water pressure across the GTA — same day. Call: 647 206 3327