Field guide for Burlington owners
Diagnosing Low Water Pressure
Weak water pressure has a dozen possible causes, and several of them take two minutes to rule out. Working through a few checks yourself tells you whether the problem is one tap, the whole house or the supply.
- Steps you can safely take yourself
- What it looks like in Burlington houses
- When to put the wrench down and phone us
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The short answer
If only one fixture is weak, the cause is almost always at that fixture: a scaled aerator, a tired cartridge or a half-shut stop valve. If every tap is weak, look at the main shut-off, a pressure reducing valve, old piping or the service line from the street. Hot water alone running weak points toward the water heater or its connections.
Key point
Weak water pressure has a dozen possible causes, and several of them take two minutes to rule out.
Step by step
- Ask the neighbours. If they also have low pressure, the cause may be a watermain break or maintenance on the public system. Check with the municipality before anything else.
- Test hot and cold separately. Fill a container from the cold side, then the hot side, at the same tap. A big difference narrows the search.
- Clean the aerator. Twist off the end of the spout, rinse the little screen and soak it in vinegar if scale is visible. Shower heads collect the same mineral buildup.
- Check the stop valves under the sink or behind the toilet. They should be fully open.
- Check the main shut-off. After plumbing work, it is sometimes left only partly open.
- Look for a pressure reducing valve. A bell-shaped brass fitting just after the meter may have drifted or failed. See pressure reducing valves.
- Watch the meter. With every fixture off, a spinning indicator on the water meter suggests a hidden leak, which can rob pressure as well as raise your bill.
Have this ready when you call
- Which fixture, which floor
- Whether the main is closed
- Rough age of the house and heater
- Any past floods or drain work
Reading the results
| What you notice | Likely cause |
|---|---|
| One faucet weak, others fine | Aerator, cartridge or stop valve at that faucet |
| Only hot water weak | Water heater sediment, valve or fittings at the tank |
| Weak upstairs, fine in basement | Narrowed old piping, often galvanized |
| Whole house weak, sudden | Main valve, PRV failure or a supply problem |
| Whole house weak, gradual | Corroding service line or interior piping |
First move in a leak
Close the main shut-off, open a low tap to drain pressure, then call (365) 464-5184.
The moment to phone us
Once the simple checks are done and pressure is still poor, call. Also call if you hear hissing in walls, see damp patches, notice rust-coloured water or suspect a leak from the meter test. A plumber can measure static and flowing pressure, test the PRV and look at the condition of the pipes. Our pages on water pressure problems and leak detection explain what that visit involves.
Burlington specifics
Halton Region treats Lake Ontario water for Burlington, and pressure across the city varies with elevation. Homes near the lake and those higher up toward the Escarpment can see quite different readings. Some houses have pressure high enough that a reducing valve was installed to protect fixtures, and those valves wear over time.
Gradual loss of pressure is common in prewar and early postwar houses, where old galvanized pipe narrows from the inside; our galvanized pipe guide explains why. Moderately hard water also leaves scale in aerators, shower heads and water heaters, as covered in our hard water guide. If a high water bill came along with the pressure change, read water bills and leaks.
Questions we hear
Why is only my shower weak?
The shower head or the cartridge in the valve is probably partly blocked by scale. Cleaning or replacing it usually solves it.
Can water pressure be too high?
Yes. Very high pressure strains fixtures and appliance hoses. A pressure reducing valve keeps it in a safe range.
Does low pressure mean a leak?
Not always, but a hidden leak is one possible cause. The meter test with all fixtures off is a quick way to check.