A frozen pipe isn't always a burst pipe yet — but the wrong thawing method can turn it into one. Here's the safe way to handle it, and when to stop and call.
If only one faucet has no water, the freeze is likely in the line feeding that fixture. If nothing runs anywhere in the house, the freeze may be closer to the main supply line entering the home — a more serious situation that's worth a call before you do anything else.
Open the faucet the frozen section feeds first, so melting ice has somewhere to go and you can hear when water starts moving again. Then apply gentle heat to the pipe itself — a hair dryer on low, warm (not boiling) towels wrapped around the pipe, or a space heater placed a safe distance away, never touching the pipe or any flammable material. Work from the faucet end toward the blockage, not the other way around, so pressure has an escape route as the ice melts.
Never use an open flame — a propane torch or similar — on a pipe. It's a fire risk near framing and insulation, and it can damage the pipe itself. Avoid boiling water poured directly on a pipe, which can crack it from thermal shock, especially on older galvanized or copper lines.
Ice expands as it forms, so a pipe can crack or split before you ever see water — the crack just isn't leaking yet because it's still plugged with ice. Watch for bulging in the pipe, frost or moisture on the outside of it, or any sound of dripping once thawing starts. If you see or hear any of these, stop thawing, shut off the water at the nearest valve, and call.
If the frozen section is behind a wall or otherwise inaccessible, if you can't find the blockage, or if water starts leaking as it thaws, stop and call. Rushplumb dispatches a Massachusetts master plumber to Brockton in 30 to 60 minutes with the copper, PEX, and pressure-test equipment needed to repair a split the moment it's found. See the frozen pipe repair page, or call (888) 616-9423.
Shut off the nearest valve, then call. Real human, real truck if you need one.