Water Not Coming Out of Faucet: Diagnosis

You lift the handle and get nothing — or a sputter, then silence. Water not coming out of faucet fixtures is a diagnosis problem before it is a repair problem, and the single most useful move takes ten seconds: check another faucet. Whether the failure is one fixture or the whole house splits the possibilities cleanly in half, and from there a short decision tree isolates the cause in minutes. The most common culprit is a $0 fix (a clogged aerator or a bumped shutoff valve); the worst cases are frozen pipes and dead well pumps. Work the tree in order.

Step 1: Isolate — One Fixture or the Whole House?

Test the tree systematically:

1. Same faucet, other temperature. Cold works but hot doesn’t (or vice versa)? The problem is on one supply line — hot-only failure points at the water heater’s shutoff, a failed hot stop, or a frozen hot line.
2. Other faucets in the same room, then other floors. One dead fixture = local problem (aerator, cartridge, stops). One dead bathroom = branch line issue. Everything dead = whole-house.
3. Whole house dead: check the neighbor or the street. A neighbor with no water, or utility trucks on the block, ends your diagnosis — call the utility. Municipal work and main breaks are more common than any home failure.

One Fixture: The Aerator Is Suspect #1

The aerator — the screened tip of the spout — catches every particle of sediment, pipe scale, and mineral grit, and it is the number-one cause of low-to-no flow at a single faucet, especially after any plumbing work or water heater replacement dislodges debris. Unscrew it by hand or with tape-padded pliers (counterclockwise viewed from below), and check the flow with it off. Strong flow bare = clean or replace the aerator: soak parts in white vinegar 30 minutes, brush the screen, reassemble ($3-$8 for a new one; note “cache” hidden aerators on modern faucets need a plastic key, usually included with the faucet or $2 online). Pull-down kitchen sprayers add a second clog point: the spray head itself and the check valve where head meets hose — unscrew the head and test flow from the open hose.

Still Dead? Cartridge Debris and Supply Stops

If flow is dead even with the aerator off, work backward:

• Supply stops (shutoff valves) under the sink. Verify both are fully open — counterclockwise. Stops get bumped by stored items, and old multi-turn stops fail internally: the handle turns but a corroded washer or broken stem stays closed. Test by closing the stop, cracking the supply nut above it over a bowl, and reopening — no water at the nut means a dead stop ($8-$15 quarter-turn replacement, a 20-minute job with the main off).
• Kinked or blocked supply lines. Braided connectors kink behind pull-out organizers; some cheap connectors’ rubber liners delaminate and seal themselves shut. Swap suspect lines ($6-$12).
• Cartridge debris. Solder balls, PEX shavings, and scale lodge in the cartridge inlets — classic after a remodel or heater swap. Shut the stops, pull the handle and cartridge (see your faucet brand’s clip or bonnet arrangement), and inspect the inlet ports; flush the faucet body by cracking the stops briefly with the cartridge out and a towel over the hole. Clean or replace the cartridge ($15-$40; free under Moen/Delta/Kohler lifetime warranties).

Whole House or Whole Branch: The Big Four

• Main shutoff partially closed. Check both the house-side main (basement, crawlspace, garage) and the meter valve. Gate valves fail half-closed; a gate can even drop off its stem and block the line while the handle spins freely.
• Frozen pipes. In freezing weather, no-flow at fixtures on exterior walls or over crawlspaces is ice until proven otherwise. Open the faucet, warm the suspect run with a hair dryer or heat lamp working from the faucet backward — never a torch — and watch for the telltale trickle as it clears. A pipe that froze once will freeze again: insulate it, air-seal the cavity, or add heat cable ($30-$60 per run).
• Pressure regulator (PRV) failure. Homes with a bell-shaped brass regulator near the main can lose flow when the PRV’s diaphragm fails closed or its strainer packs with debris. Symptom: weak-to-no flow everywhere, sometimes with hammering or fluctuation first. Test with a $12 gauge on a hose bib — under ~20 psi with the utility confirming normal street pressure means a dead PRV ($80-$150 part, $250-$500 plumber-installed).
• Water heater issues (hot side only). Confirm the heater’s cold inlet valve is open; sediment or a collapsed dip tube can choke hot output, and a heat-trap nipple clogged with scale kills hot flow at every tap.

Airlocks and Sputtering

Air trapped after plumbing work or an outage causes spitting, banging, or a vapor-locked dead leg — most common on low-pressure and gravity-fed hot lines. The cure is flushing: open the affected faucet fully, then open the highest and lowest faucets in the house and let everything run 2-3 minutes until flow is smooth. Stubborn hot-side airlocks clear with the hose trick: connect a hose (or a washing-machine-style bridge) from a working cold tap to the airlocked hot tap and open both for 30 seconds, letting cold pressure push the air back through.

Well Systems: A Different Tree

On a well, whole-house no-flow points at the pump system: check the breaker for the pump circuit first (tripped breakers are the #1 well “failure”), then the pressure gauge at the tank — zero psi with the breaker on suggests pump, pressure switch, or wiring failure; the pressure switch’s contacts ($25 part) burn out far more often than the pump itself. A waterlogged pressure tank (short-cycling before failure) and a stuck check valve round out the usual suspects. Pump replacement runs $1,000-$3,500 for submersibles — get the switch and controls tested before authorizing a pump pull.

Special Cases: Touchless Faucets, Filters, and RO Systems

Modern kitchen gear adds three failure modes the classic tree misses. Touchless and touch-activated faucets (Moen MotionSense, Delta Touch2O) run their water through a solenoid valve powered by batteries or an AC adapter — dead batteries or a failed solenoid means no water even though the plumbing is perfect. Symptom: manual mode may still work, or nothing works; fix: replace the six AA batteries in the under-sink control box first ($5 test), then the solenoid ($40-$80, warranty-covered on both brands). Under-sink filters choke flow as cartridges load up — a filter at the end of its life can drop a dedicated drinking faucet to a dribble, and a bypassed or wrongly seated cartridge after a change can stop it entirely. Reverse osmosis faucets depend on tank air pressure: a dead-empty RO faucet usually means a waterlogged storage tank (check the schrader valve on the tank; it wants 7-8 psi empty) or a clogged prefilter starving the membrane. In all three cases, the giveaway is that every other faucet in the house runs fine — which the ten-second isolation check in step one already told you.

Tools and When to Call the Plumber

A prevention note worth thirty seconds: after any future plumbing work — heater swap, valve replacement, a street-side utility repair — remove your faucet aerators before repressurizing the house and run each tap wide open for a minute. The debris that would have packed the aerators and cartridge inlets flushes harmlessly down the drain instead, and you skip this entire diagnostic next time.

Everything above needs only tape-wrapped pliers, an adjustable wrench, a flashlight, vinegar, and a $12 pressure gauge. Call a pro when: the main or meter valve is seized or broken (utility handles the street side free), a frozen section has burst (shut the main first), the PRV needs replacement and there’s no isolation valve, well diagnostics go past the switch, or you find galvanized supply pipes choked with 60 years of scale — that last one is a repipe conversation, not a repair. For everything else, the tree above finds the blockage faster than a service call books one: isolate, check the aerator, check the valves, then work back toward the meter.