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Weak flow or low pressure at one faucet or shower.

A homeowner or trained tech can open stops and clean aerators and cartridges with the water shut; a licensed plumber should replace an in-wall valve or re-pipe the branch, and a licensed gas technician services a gas tankless heater.

Customers put it like this

  • The kitchen faucet is just a trickle
  • The shower is weak but the sinks are fine
  • Hot water barely comes out of one tap
  • The outside spigot only dribbles
Prepare this job in ForeBotFind another guide

Stop first if

  • Gas smell, a carbon monoxide alarm, or soot at a gas water heaterGet everyone out and call the gas utility from outside. Nobody works on the heater.
  • Water has reached outlets, a panel or the wiring of a sensor faucetStay out of the water. Call the electric utility or a licensed electrician before anyone goes in.
  • Water runs and will not shut off at the fixture stop, a branch valve or the mainKeep people and power away from the water and call for emergency plumbing service now.
01

Ask on the call

7

Homeowner? These are the questions a good technician will ask you. Having the answers ready makes the first visit count.

  1. Which fixture is weak, in which room, and what brand is it if you can read it?
  2. Does water come out weak when it is on, drip when it is off, or drain slowly?
  3. Is it weak on hot, cold or both at that fixture?
  4. Did it start after plumbing work, a new faucet, cartridge or aerator, or a freeze?
  5. Is the shutoff under it fully open, and has anyone cleaned the aerator or showerhead?
  6. Do faucets on this floor and other floors run normally, hot and cold?
  7. Is the hot water from a tankless heater or a tank, and are you on city water or a well?
02

Bring

6
  • Aerator key and spare screens
  • Bucket and a timer
  • Descaler and a small brush
  • Pressure gauge for a hose bibb
  • Spare supply connectors
  • Flashlight
03

Check on site

7
  1. Run a faucet on another floor or branch, hot and cold. If it is weak too, handle it as a house-wide pressure problem, not this fixture.
  2. At the weak fixture, run hot and then cold. An aerator serves both sides, so weak on one side only points behind it.
  3. Open the stop under the fixture and the handle all the way, counting the turns, and test hot and cold again.
  4. Shut the water to the fixture, then remove and clean the aerator, showerhead or sprayhead screen. Test hot and cold again.
  5. Read the faucet or valve brand first. With the water shut, lift the cartridge and clear scale or debris from its ports. A balancing shower valve needs both supplies open.
  6. On a tankless heater, open every valve and watch its flow display. If other hot taps run fine, the heater is not where it starts. Its filter is a technician's job.
  7. Look behind the fixture for a kinked or clogged connector, many fittings, or old galvanized pipe. A licensed plumber re-pipes a restricted run.
04

Keep on the record

5
  • Fixture room, type and brand, with a photo of the label or old part
  • Timed bucket fill on hot and on cold, before and after each step
  • Stop position and how many turns it took to open fully
  • Which other taps were tried, and whether any was weak
  • Photo of what came out of the aerator or cartridge

General guidance for a qualified person, not a finding about any home. The person on site decides.