First: Is It Sudden or Gradual?
Sudden loss usually indicates:
- Municipal issue
- Shut-off valve problem
- Pipe break
- Specific fixture failure
Gradual decline usually indicates:
- Pipe corrosion/buildup
- Water heater sediment
- Failing pressure regulator
This distinction helps narrow down the cause.
Check #1: Is It the Whole House or One Fixture?
One Fixture Only
The problem is localized:
- Clogged aerator (most common)
- Supply line kink or blockage
- Fixture valve issue
Fix: Remove the aerator, clean it, and reinstall. If that doesn't work, check the supply valves under the fixture.
Whole House
The problem is systemic — keep reading.
Check #2: Is It Hot, Cold, or Both?
Only Hot Water Is Weak
Problem is likely:
- Water heater sediment buildup
- Water heater shut-off partially closed
- Hot water line corrosion
Only Cold Water Is Weak
Problem is likely:
- Cold supply issue
- Cold-side valve partially closed
Both Hot and Cold
Problem is:
- Main supply issue
- PRV (pressure reducing valve) failure
- Municipal issue
Check #3: Check With Your Neighbors
If neighbors also have low pressure: It's a municipal issue. Call 311 (Vancouver) to report and get an estimated fix time.
If only your house is affected: The problem is on your side of the meter.
Common Causes and Fixes
1. Main Shut-Off Valve Partially Closed
Maybe someone turned it for maintenance and didn't fully reopen it.
Check: Locate your main shut-off. Make sure it's fully open (counterclockwise until it stops, or lever parallel to pipe).
2. Pressure Reducing Valve (PRV) Failure
Most Vancouver homes have a PRV where water enters the house. It reduces high street pressure to safe levels. When it fails, pressure drops.
Signs: Whole-house pressure loss, both hot and cold
Fix: PRV replacement ($150-300 installed)
3. Pipe Leak
A leak somewhere in the system diverts water before it reaches fixtures.
Signs:
- Water bill increase
- Wet spots on walls/floors/yard
- Sound of running water
Fix: Find and repair the leak
4. Corroded/Clogged Pipes
Older galvanized steel pipes corrode inside, restricting flow.
Signs:
- Gradual pressure loss over years
- Rusty water
- Old galvanized plumbing visible
Fix: Pipe replacement (the only permanent solution)
5. Water Heater Sediment
Sediment builds up in water heaters, restricting flow — especially to hot water fixtures.
Signs: Low hot water pressure specifically
Fix: Flush the water heater. If severe, may need professional cleaning or replacement.
6. Clogged Aerators and Showerheads
Mineral deposits clog the small holes in aerators and showerheads.
Signs: Low pressure at specific fixtures only
Fix: Remove aerator, soak in vinegar, clean with old toothbrush, reinstall. Same for showerheads.
7. Municipal Supply Issues
Construction, main breaks, or flushing can temporarily affect pressure.
Signs: Neighbors also affected, often temporary
Fix: Wait it out or call 311 for info
8. Peak Usage Times
In some areas, pressure drops during high-usage times (morning, evening).
Signs: Pressure fine at some times, weak at others
Fix: This is usually a municipal capacity issue — not much you can do except use water during off-peak hours.
When to Call a Plumber
Call if:
- Whole-house pressure loss and neighbors are fine
- Pressure loss with signs of leaking
- Old pipes and gradual pressure decline
- PRV needs replacement
- You can't identify the cause
Pressure issues can indicate serious problems. Better to diagnose than guess.