One fixture
- Clogged aerator or shower head
- Worn cartridge
- Partly closed stop valve
Whole house
- Main valve partly closed
- Failing pressure-reducing valve
- Galvanized pipes
- Undersized service
- Municipal supply issue
Hot only
Water heater valve or sediment.
Check with neighbours to see if the issue is widespread.
Help
Testing pressure
Screw a gauge onto an outside tap or the laundry faucet to read psi. Compare with what your municipality or plumber considers normal. Very high pressure is a problem too, causing banging pipes and dripping relief valves.
Pressure-reducing valves
Many homes have a PRV after the main shut-off. When it fails, pressure can drop or spike. Adjusting or replacing it restores normal pressure.
Galvanized pipe
In older homes, galvanized steel pipe rusts inside, narrowing the passage. Low pressure that worsens over years is a classic sign. Replacement with copper or PEX is the cure.
Well systems
On a well, low pressure may come from the pressure tank, switch or pump. These need a different approach.
When to put the tools down
Some of this is homeowner work and some is not. Stop and phone us if you see any of these:
- Water meter dial moves with every tap off
- Pressure drops when two fixtures run
- Green crust on copper joints
- Banging when a valve closes quickly
- Anything involving the gas line, the venting or cutting into a wall
Quick answers
Could the city be the cause?
Watermain work or breaks nearby can reduce pressure temporarily. Neighbours noticing the same thing is a strong clue.
Why is just the hot side weak?
Look first at the heater's own valves, then for grit in the tank or a worn mixing cartridge.
Could my softener be cutting flow?
A plugged resin bed or bypass valve partly closed can reduce flow through the whole house.