You drip faucets when it’s cold to keep pipes from freezing and bursting by keeping water moving and relieving pressure inside the pipes.

Quick Scoop: Why you drip faucets when it’s cold

When a hard freeze hits, the water sitting inside your pipes can freeze, expand, and build pressure until the pipe cracks or explodes behind walls, in crawl spaces, or in basements. Letting a faucet run at a slow trickle keeps the water moving, which makes it harder for it to freeze solid and gives any expanding ice somewhere to relieve pressure instead of bursting the pipe.

Think of it like slightly opening a valve on a pressure cooker: a tiny release of water flow can save you from a much bigger, messier blow‑out later.

What actually happens inside your pipes

  • When temperatures drop below freezing, standing water in pipes—especially in exterior walls, unheated basements, attics, and crawl spaces—can start to freeze.
  • As water turns to ice, it expands and squeezes the remaining liquid water between the ice blockage and the closed faucet, raising internal pressure.
  • Pipes usually fail not at the ice plug, but somewhere between the blockage and the faucet where pressure has nowhere to go.
  • A slow drip keeps water moving and lets pressure escape through the open faucet instead of through a crack in the pipe.

In short, a controlled drip is a cheap insurance policy against a catastrophic leak that can wreck floors, drywall, and wiring.

Do you always need to drip faucets?

Experts and organizations like the Red Cross say you should let faucets served by exposed or vulnerable pipes drip during very cold weather to help prevent freezing. But that does not mean running every faucet in the house all winter long.

You mainly consider dripping when:

  • Forecast lows are at or below about 20°F (around −6 to −7°C), especially for several hours overnight.
  • Your plumbing runs through exterior walls, unheated garages, basements, attics, or crawl spaces.
  • You’ve had frozen pipes before, or you live in a region not used to extreme cold (homes often have less insulation).

If it’s just slightly below freezing for a short time and your pipes are well insulated inside conditioned spaces, dripping may not be necessary.

How to drip faucets the smart way

You don’t need a stream of water—just a tiny, steady trickle.

  • Pick the right faucets
    • Prioritize faucets on exterior walls.
* Include faucets supplied by pipes in unheated areas (basements, attics, crawl spaces, garages).

* Consider dripping at least one hot and one cold faucet in high‑risk areas if possible.
  • How much water to run
    • Aim for a thin, pencil‑lead‑sized trickle—just enough that the water clearly flows, not merely forms a single hanging drop.
* This helps balance water savings with freeze protection.
  • When to start and stop
    • Start dripping before the coldest part of the night when temps are expected to fall below freezing for several hours.
* You can usually stop once temperatures rise well above freezing and stay there.

A lot of homeowners now pair dripping faucets with pipe insulation and sealing up drafts as their standard “cold wave” routine, especially after recent winter storms across the U.S. exposed how vulnerable older plumbing systems can be.

Isn’t that a waste of water?

There is a trade‑off: a dripping faucet does use extra water, and water‑conscious homeowners rightly worry about waste and higher bills. But a small, temporary increase in water use is usually far cheaper than repairing burst pipes and fixing resulting water damage to walls, ceilings, and flooring.

Many plumbers recommend:

  • Only dripping the most at‑risk faucets, not every tap in the house.
  • Combining dripping with other measures (pipe insulation, opening under‑sink cabinets to let warm air in, sealing gaps around pipes where cold air enters).

That way you’re using just enough water to protect your system without being careless.

Quick FAQ style wrap‑up

  • Why do you drip faucets when it’s cold?
    To keep water moving and relieve pressure so pipes are less likely to freeze and burst.
  • Which faucets should I drip?
    Those fed by pipes in exterior walls or unheated spaces like basements, attics, garages, or crawl spaces.
  • How much should they drip?
    Just a small trickle, not a full stream.
  • Is this still common advice now?
    Yes—recent cold waves and winter storms keep bringing this topic back into the news and forums every winter as people trade tips on preventing frozen pipes.

Information gathered from public forums or data available on the internet and portrayed here.