Low Water Pressure: Causes and Fixes

The short version

When a single tap is weak, the fault usually lives at that tap: a plugged aerator, a scaled showerhead or a worn cartridge. If every tap is weak, start with the main valve, the pressure-reducing valve, the water service line or a hidden leak. Hot side only? Then suspect the water heater or its valves. Sorting the problem into one of those groups tells you most of what you need to know.

The routine, in order

1. Compare fixtures. Run cold, then hot, at several taps on different floors. Note which are weak.
2. Clean aerators and showerheads. Twist them off and leave them an hour in vinegar. Milton's hard water packs these with scale.
3. Check the main valve. Turn the main valve all the way open. A half-closed valve after some old repair is more common than you might think.
4. Look for a regulator. Plenty of houses have a regulator just past the meter. They fail or drift over time.
5. Test the pressure. A screw-on gauge at an outdoor faucet or laundry tap gives a static reading. Compare it with what feels normal.
6. Check for leaks. Shut off every fixture and watch the meter. Any movement means water is escaping somewhere.

Mistakes to avoid

• Cranking a pressure regulator up without a gauge. Too much pressure strains every fixture and appliance in the house.
• Replacing a faucet when the cartridge or aerator was the problem.
• Ignoring a gradual decline over years. Galvanized pipe and undersized services narrow slowly, and the trend matters.
• Forgetting the filter. Whole-house filters and softeners with clogged cartridges or resin restrict flow.
• Assuming the town's supply is the culprit before checking inside the house.

Older Milton homes with galvanized steel or small copper services lose pressure as the pipes corrode inside. Newer homes more often have regulator or fixture issues. Rural homes on wells have a different set of causes again, starting with the pressure tank and pump switch.

When to ring the shop

Call when cleaning fixtures does not help, when the whole house is affected, when the meter shows a leak, or when the pressure gauge reads unusually low or high. We can test pressure properly, replace regulators and valves, and tell you whether the service line or interior pipes are the bottleneck. Where an old line is the cause, water service line replacement or repiping may be the real fix. Sometimes a main sewer line cleaning gets booked in the same visit, though that is a drain issue, not a pressure one.

If pressure drops suddenly across the whole house, check with neighbours first. A town watermain repair affects everyone on the street.