Short answer: Drip your faucets when outdoor temperatures are expected to stay at or below freezing for an extended period, typically when forecasts show 32°F (0°C) or lower for several hours. Details and guidance

• When to drip
  • If temperatures are forecast to stay at or below freezing for a few hours (commonly 3–6 hours or more), start dripping outdoor and interior faucets.
  • Begin earlier if you have uninsulated or exposed pipes, especially those on exterior walls or in crawl spaces/garages.
• Which faucets to drip
  • Drip from faucets on the exterior walls and the farthest point from your water meter, as those are the most vulnerable.
  • If you have a split or multi-line system, drip both hot and cold lines where accessible to ensure water movement through the entire run.
• How much to drip
  • A slow, steady drip is recommended—roughly a small trickle, about one drop every few seconds. The goal is continuous water movement to prevent pressure buildup and freezing.
  • In very cold conditions (well below freezing), you may increase to a slightly faster drip, but avoid wasting water.
• Additional tips
  • Open cabinet doors under sinks on exterior walls to allow warmer room air to circulate around pipes.
  • Keep a consistent temperature inside; avoid drastic drops in indoor temperature.
  • Disconnect outdoor hoses and drain exterior faucets to reduce risk of freezing.
• After the cold snap ends
  • Once temperatures consistently stay above freezing, you can stop dripping. Check for any hidden or remote risers that may have frozen and thawed, and inspect for leaks.

If you’d like, tell me your location and the forecast window, and I can tailor the drip plan (which faucets to target and for how long) to your climate.