Shower water pressure is low: what to check

One shower that dribbles while the remaining taps flow normally has a local fault. If everything dribbles, suspect the house supply, the pressure regulator or the utility. Both situations start with the same two-minute test: run a few other taps. Faucet, shower and disposal jobs are grouped under our garbage disposal installation page.

What makes one shower weak when the sinks are fine?

Typical causes: scale or grit in the showerhead, a stop that was never fully opened, a worn cartridge, or a diverter that does not seat. California caps showerheads at 1.8 gallons a minute, at a test pressure of 80 psi, so a gentle spray is normal and an abrupt decline is not. Begin with the cheapest remedy.

Try these in order:

1. Clean the head. Remove it, steep it in white vinegar for roughly an hour, then poke the nozzles clear with a toothpick. Anaheim's hardness page lists about 300 ppm, and that level of minerals clogs spray holes within months.
2. Check the screen. A small filter screen sits at the arm connection and catches grit after plumbing work.
3. Run the arm bare. Strong flow without the head means the head was clogged. Weak flow there shifts suspicion to the valve or supply line.
4. Look at the shower valve. A worn cartridge or debris in the valve cuts flow; replacing a cartridge is a routine repair.
5. Check any inline shutoff. Some showers have stops in the wall that were never opened fully.

The EPA notes that WaterSense showerheads include pressure compensation to keep flow steady across pressure ranges, so a WaterSense-labeled head is one route to a decent spray at modest flow.

No pressure at the tub, plenty elsewhere: what gives?

If the tub spout or shower is weak while the sink in the same room runs well, the problem is in that fixture's own branch: the valve, the diverter or a partly closed stop. Hot only or cold only low pressure points to a stop, a cartridge or a clogged inlet on that side. Moen lists a stuck cartridge or spool among the usual causes.

Try both temperatures separately. If only one side is weak, the problem is on that supply. Compare the tub spout with the showerhead too: a diverter that leaks sends water to the tub when you want the shower, which also looks like low pressure.

When is it the whole house?

If every tap and the shower are weak, check the main shutoff, which may be partly closed, then the pressure regulator near the main and the meter. A pressure gauge threaded onto an outdoor hose bib gives the reading. Homes commonly see 40 to 80 psi, and as we understand California's plumbing code, a regulator is expected once street pressure climbs past 80.

Improving weak pressure through the house goes through leaks, old galvanized lines clogged with scale and utility-side causes. Hidden leaks sap pressure as well, and the EPA's two-hour meter test is a way to find one. A plumber can test the regulator, and our page on plumbers for low water pressure covers that visit. How a regulator is set is explained in adjusting a regulator valve, though swapping one belongs with a plumber.

Can a shower pipe burst, and how would I know?

Yes. A split supply line behind a shower wall causes sudden pressure loss, hissing or spraying sounds, damp drywall, ceiling stains below, and a dial that turns when everything is off. Suspect it? Shut the main water valve immediately and phone a plumber afterward.

Do not open the wall yourself unless you can see the break, because water near wiring is a hazard. Signs and first steps are laid out in recognizing a burst pipe. Take photographs of any damage before cleanup.

What should I know about installing a garbage disposal such as the InSinkErator Badger 500?

Installation follows the manufacturer's manual, and the one for your exact model should be in hand. For InSinkErator Badger units it covers a mounting assembly under the sink flange, the drain connection, an optional dishwasher inlet and the electrical hookup. The same sequence applies broadly to other brands, including American Standard and Glacier Bay units, though each uses its own mounting parts.

From the Badger manual: if a dishwasher is going to connect, punch out the drain plug in the disposal inlet first, since the plug cannot go back in. The three mounting screws are drawn up evenly against the backup flange. The unit then lifts and latches onto the mounting ring. Hardwired models need power off at the breaker, and the ground wire goes to the green screw.

Plumbing-wise, the disposal discharges into the sink trap and drain, and a P-trap must connect after it. Many owners prefer a plumber for the drain and electrical parts, particularly in older Anaheim and Fullerton kitchens where the pipes under the sink may be corroded. We cover the dishwasher side in garbage disposal installation with a dishwasher connection.

Is sink plumbing different in a mobile home?

Often, yes. Manufactured homes can use different supply materials and tighter spaces under sinks, and drain lines may be lighter weight than in a conventionally built house. Check what you have before buying parts. We have not verified a single rule that applies to all of them, so treat any quick answer with caution.

Winter is not a major factor in Orange County, but if you have a vacation property, see winterizing mobile home plumbing. A plumber can identify the pipe type, and parts should match it. To discuss a fixture or pressure problem, use our quote form.