Why Is My Water Pressure Low?

Is low pressure affecting one fixture or the whole house?

The first question narrows everything. Walk around and test sinks, showers, tubs and outdoor spigots, using both hot and cold. Write down which ones are weak.

One fixture points to the fixture. Several fixtures on one side of the house point to a branch line. Hot water only points to the water heater or its piping. Everything at once points to the supply, the main valve or the regulator.

• One faucet, hot and cold: aerator or the fixture itself.
• One faucet, only hot or only cold: a partly closed or failing supply valve, or a clogged cartridge on that side.
• Only hot water everywhere: sediment in the water heater, a partly closed valve at the heater, or corroded hot lines.
• All fixtures, all the time: main shutoff, regulator, main line, or supply from the utility.
• Worse at certain times of day: demand on the neighborhood system or in the house.

Which clogged aerators, valves and regulators cause it?

Start with the cheap, simple causes. Mineral deposits are common in valley homes because hard water leaves scale, and your water utility publishes a water quality report you can check for your own area.

1. Unscrew the aerator at the faucet tip, rinse out grit and soak it in vinegar to loosen scale, then put it back.
2. For a showerhead, do the same with the nozzles and the small screen behind them.
3. Check that the shutoff valve under the sink or behind the toilet is fully open. A valve that was only partly reopened after a repair is a frequent culprit.
4. Check the main shutoff near where water enters the house. Gate valves can stick or wear, and a half-open main restricts everything.
5. Find the pressure regulator, a bell-shaped valve near the main, if your home has one. A failing regulator can drop pressure for the whole house, and it should be tested with a gauge rather than adjusted by guesswork.
6. Attach a simple hose-bib pressure gauge to an outdoor spigot to get an actual reading before deciding anything.

When does low pressure signal a water line problem?

If cleaning and valve checks change nothing, the cause may be in the pipes. Older galvanized steel supply lines corrode from the inside and narrow over time, so pressure fades gradually and the water may look rusty. Copper and plastic lines can also fail, and mineral scale slowly narrows any pipe.

A leak is another cause. Water escaping from a buried or hidden line means less reaches the fixtures. Warning signs include a water meter that moves when everything is off, a wet or unusually green patch in the yard, a sound of running water at night, and a higher water bill with no change in use.

Check the meter yourself: shut off all water use, then see whether the dial or leak indicator keeps moving. If it does, you have a leak somewhere downstream, and a plumber can help you track down where the water is going.

Could the problem be outside your house?

Sometimes the issue is not yours. Utility maintenance, a main break in the street or heavy seasonal irrigation demand can lower pressure for the neighborhood. If neighbors have the same issue, call your water utility.

Homes at the higher end of a hillside, or far from the main, may naturally have lower pressure. The reverse also happens: homes at the bottom of a hill can have pressure so high it stresses fixtures, which is why regulators exist.

When should you call a plumber?

Call if the weakness affects the whole house, if cleaning aerators does nothing, if the water is rusty, if the meter moves with everything off, or if you see wet spots or hear running water. Also call if the regulator needs replacing or the supply line looks corroded.

Rocket is based in West Jordan and serves the Salt Lake Valley. You can call or text (385) 722-7638, or schedule online, and describe which fixtures are affected, which saves time on arrival.