Before you start
Decide whether the problem affects one fixture, one type of water, or the whole house. That single observation eliminates most possible causes before you pick up a tool.
| Pattern | Likely cause |
|---|---|
| One faucet only | Clogged aerator or cartridge |
| Hot water only | Water heater valve, sediment or scale in a tankless unit |
| Whole house, sudden | Partly closed main valve, municipal work or a leak |
| Whole house, gradual | Corroded galvanized pipe, failing regulator, ageing service line |
Step by step
- Check the aerator. Remove the spout's tip and wash away grit and scale.
- Compare hot and cold. If only hot is weak, look at the heater's valves and sediment.
- Inspect the main valve. Make sure it is fully open; a previous repair may have left it partly closed.
- Ask your neighbours. If they share the problem, the cause may lie in the municipal system; the Region of Peel posts notices of water main work.
- Look for a regulator. Some homes have a bell-shaped pressure-reducing valve near the main; these fail with age.
- Check for leaks. With all fixtures off, watch the meter. Movement suggests a hidden leak.
- Identify the pipe. Grey threaded steel pipe near the meter suggests galvanized supply that narrows from within.
Mistakes to avoid
- Adjusting a regulator blindly. Turning it up without a gauge risks pressure high enough to damage fixtures.
- Replacing fixtures first. A new faucet will not help if the supply pipe is the restriction.
- Ignoring a sudden drop. A rapid loss of pressure can signal a burst pipe somewhere out of sight.
A note on testing with a gauge
A simple pressure gauge that threads onto an outdoor faucet or laundry tap gives an objective reading. Test with every other fixture closed, then again with a shower running, and note the drop. A large fall under modest demand points toward a restriction in the supply piping rather than low pressure from the street. Recording the readings helps a plumber diagnose the problem quickly.
When to call
Call when the problem is house-wide and gradual, when the meter moves with taps closed, or when you find old steel pipe. Solutions range from leak detection to repiping or water service line replacement. Weak hot water from a tankless unit is often cured by tankless descaling. Unusual odours are a separate topic, covered in sewer smell in the house, and fixture tips are in cleaning a faucet aerator. Keep the gauge afterward; a yearly reading creates a simple history that shows whether the problem is slowly worsening. That history can also reveal a regulator gradually drifting out of adjustment.
Worth knowing
Answers our Mississauga crew gives most
What pressure should a house have?
Many homes fall roughly between 40 and 80 psi. A gauge on an outdoor faucet gives a quick reading.
Can a water softener reduce pressure?
A clogged or undersized softener can. Its bypass valve lets you test whether it is the cause.