Frozen Pipes In NJ

A frozen pipe is a water problem before it is a plumbing problem. The ice itself rarely does the damage. What does is the pressure that builds behind it, and the water that comes out once the ice lets go.

In New Jersey, that risk shows up in a handful of nights each winter, usually when a cold snap drops overnight lows into the teens. Most homes ride those nights out without trouble. The ones that don’t tend to share the same weak spots: a kitchen sink on an outside wall, a line through an unheated crawlspace or garage, an addition built over a slab or a porch.

This guide covers when pipes freeze, which ones go first, how to tell a frozen line from other water problems, and why a frozen pipe doesn’t always burst, but sometimes breaks hours after it thaws. If a pipe has already split and water is moving, shut off the main and call for emergency plumbing now.

My Pipes Are Frozen: What To Do Right Now

A frozen pipe is an emergency, and not because the faucet is dry. The line behind the ice is still under pressure. When it lets go, a plumber needs to be there to make sure the water drains where it should and, if the pipe split, to shut it down before it damages the house. Until then, do these:

• Open the faucet on the frozen line, hot and cold, and leave it open. It gives the pressure building behind the ice a way out.
• Make sure the drain is clear. Pull the stopper and clear out dishes or anything sitting in the sink. When the line frees up, water can come all at once, and it needs somewhere to go.
• Open the cabinet doors under the sink, and the door to any cold room the pipe runs through, so the heat already in the house can reach the line. Keep the thermostat steady and don’t turn it down.
• Call an emergency plumber right away. Don’t wait to see whether it thaws on its own. Thawing is when a hidden crack starts leaking.
• Know where your main water shutoff is. In most NJ homes it’s where the service line comes through the basement or crawlspace wall, near the meter. If you see a split, a bulge, or water coming through a ceiling or wall, close it and keep clear of outlets and appliances.

No Water Coming Out Of Any Faucet

If every fixture is dry during a cold snap, the freeze is likely at the point where water enters the house: the service line, the meter, or the main shutoff area. Check with a neighbor first. If their water is out too, the problem may be on the utility’s side, so call your water company. If only your house is out, a plumber needs to find where the line froze.

If pressure has been weak for weeks regardless of the weather, the cause is more likely something other than ice. Our guide to low water pressure in the house walks through those patterns.

How To Tell If Your Pipes Are Frozen

The clearest sign is a faucet that gives a trickle or nothing on a cold morning while other fixtures run normally. A frozen line is local. It knocks out the fixtures fed past the ice, not the whole house.

What To Check In Your NJ Home

• Which fixtures are affected. Kitchen dry but the upstairs bath runs? The line to the kitchen is the suspect, especially if the sink sits on an outside wall.
• Exposed pipe in the basement, crawlspace, garage, or under the sink for frost, condensation, or a bulge.
• The toilet. One that won’t refill after a flush on a cold night points to a frozen supply line.
• Sound. Sputtering, clanking, or air with little water behind it when the faucet opens.
• Ceilings and walls below and beside the fixture for damp spots or stains.
• The outdoor spigot and the wall behind it, inside and out.

Only The Hot Water Pipe Is Frozen

The hot and cold sides run on separate lines, so one can freeze while the other flows. When only the hot side is out, the hot line is usually the one routed along a colder wall, through a cold cabinet back, or across a crawlspace. It is still a frozen line, handled the same way: faucet open, heat up, watch for leaks.

How To Tell If A Frozen Pipe Has Burst

A frozen pipe and a burst pipe can look the same at first: no water. The difference shows up as the line thaws.

• Water where it shouldn’t be: dripping, a wet ceiling, a puddle near a wall, or water running in a wall you can hear.
• A visible split, bulge, or separated fitting on exposed pipe.
• The water meter keeps moving with every fixture off.
• Pressure drops sharply once water comes back.

Any of these means the problem is no longer the ice. Close the main shutoff and go straight to burst pipe repair.

Should You Thaw Frozen Pipes Yourself?

No. Thawing is the riskiest moment for a frozen pipe, because it’s when a crack that formed in the cold starts to leak. A plumber thaws the line with the water controlled and the leak check ready, so a split gets caught at the pipe instead of through your ceiling.

Can I Use A Hair Dryer On A Frozen Pipe In My Basement?

We don’t recommend it. Even on a pipe you can see, a hair dryer means electricity near water and a thaw no one is watching for leaks. It also does nothing for the part of the line inside a wall, which is often where the ice is. Some homeowners get lucky and the line comes free without damage. When it doesn’t, the leak starts the moment the ice lets go, with the water still on. Close the main, open the faucet, and call.

What Never To Use

• Torches, propane or kerosene heaters, or any open flame. Framing, insulation, and dust near pipes catch fire.
• A space heater left running unattended near the pipe.
• Anything that heats the pipe hard and fast, which can crack it or a weakened joint.

What Can I Pour Down The Drain To Unfreeze Pipes?

Nothing. Drains and water supply lines are separate systems. Hot water, salt, or a chemical drain cleaner poured into a sink only goes into the drain, and never reaches a frozen supply line. Chemical cleaners and boiling water can also damage older drain pipes and plastic fittings.

How Plumbers Thaw Frozen Pipes

A freeze call is a diagnostic visit first. A licensed plumber locates the frozen section, thaws it in a controlled way, then pressure-checks the line before calling it done. That last step matters: a joint that cracked while frozen may not leak until the system is back at full pressure. Where damage is hidden behind finished surfaces, leak detection pinpoints the break so only the wall or ceiling that needs opening gets opened.

When To Call A Plumber For Frozen Pipes In NJ

Right away. A frozen pipe is a plumbing emergency because the system is still under pressure behind the ice. That pressure keeps building while the line stays frozen, and it all releases the moment the ice gives. With a plumber on site, the water drains where it should, and a split pipe gets shut down before it floods a ceiling, a finished basement, or the walls. It’s even more urgent if:

• The frozen section is inside a wall, ceiling, or floor, or you can’t find it.
• You see a bulge, crack, or separated fitting, or any water.
• No water is coming out anywhere in the house and the utility says its side is fine.
• The line has stayed frozen for hours after the house warmed up.
• The same pipe froze last winter.
• The home is a rental, vacant, or one you are managing from a distance.

Even when one exposed line comes back on its own with no visible leak, have it pressure-checked. A crack that hasn’t leaked yet will at full pressure, and the next cold snap will find the same pipe.

Finding An Emergency Plumber For Frozen Pipes In Your Area

In New Jersey, plumbing work must be done by or under a licensed master plumber. Before you book anyone in a hurry:

• Check the license. NJ master plumber licenses can be verified through the Division of Consumer Affairs license lookup (linked below). The number should also appear on the company’s van, website, and paperwork.
• Ask how they price the visit before they arrive, including after-hours or emergency rates.
• Ask whether they pressure-test the line after thawing. A thaw without a pressure check can leave a hidden crack.
• Ask if they cover your town. In a cold snap, a company close by gets to you faster.

What Temperature Do Pipes Freeze?

Water freezes at 32°F, but pipes inside a house usually don’t freeze the moment it hits 32 outside. The house, the wall cavity, and moving water all buy time.

Field testing by the Building Research Council at the University of Illinois found that uninsulated pipes in an unheated space began to freeze once the outdoor temperature fell to about 20°F. A survey of plumbers in the same research lined up with it: burst-pipe calls started when nights dropped into the teens.

When To Worry About Pipes Freezing In NJ

Treat 20°F as the alert line, not a guarantee. Three things move it:

• Wind. Cold air pulled through a gap in the siding, a rim joist, or a dryer vent strips heat from a pipe far faster than still air. On a windy night, a line in the path of a draft can freeze well above 20°F.
• Duration. One cold hour before sunrise rarely does it. A run of days below freezing, with nights in the teens, is when NJ calls stack up.
• Where the pipe runs. A line inside the heated part of the house is protected at almost any outdoor temperature. A line outside it is exposed at the first hard freeze.

So will pipes freeze at 32 degrees? Pipes inside a heated house rarely do. An exposed outdoor spigot or a line in an open crawlspace can.

Which Parts Of An NJ Home Are Most Likely To Freeze

The pipes that freeze are almost always outside the heated part of the house, or pressed against its coldest edge. In order of how often they come up on winter calls:

1. Outdoor hose bibs (spigots). The fixture sits outside, and the short pipe feeding it runs through the rim joist. A hose left connected traps water in the spigot.
2. Pipes in exterior walls, starting with sinks. The room is warm. The back of the closed cabinet is not. The same goes for any supply line that runs up or across an exterior wall, like the riser to a second-floor bathroom. The wall cavity sits much closer to the outdoor temperature than the room does. In older NJ homes with thin or settled wall insulation, and in additions where the pipe ended up on the cold side of the insulation, that gap is enough to freeze a line on a windy night in the teens.
3. Unheated crawlspaces. Common under additions, sunrooms, and older ranch homes.
4. Garages and rooms above them. Laundry hookups and bathrooms over attached garages are a frequent NJ setup, especially in split-levels.
5. Basement rim joists. A pipe run along the top of the foundation wall, where the house meets outside air, can freeze even in a heated basement.
6. Attics. Less common here, but some homes run a second-floor supply through unconditioned attic space.
7. The water service line. The buried line from the street sits below the frost line and rarely freezes. When it does, it’s usually where it rises into the house or passes through a cold foundation wall. That’s a water line repair situation, not a fixture one.

Old or mixed piping raises the stakes. Galvanized steel corroded from the inside, copper thinned by pinholes, and polybutylene all give up sooner under freeze pressure than sound pipe does.

Do PEX And Plastic Pipes Freeze?

Yes. PEX freezes at the same temperature as any other pipe. Because it flexes, PEX tubing is more forgiving than copper and less likely to split, but the brass and plastic fittings that join it are not, and repeated freezes still wear it down. Rigid PVC and CPVC get brittle in the cold and can crack. The material changes the odds of a burst, not whether the water inside freezes.

Common Causes Of Frozen Pipes In NJ Homes

New Jersey sits in between. It gets enough hard freezes to matter, but not so many that every house was built for them. Most frozen pipes here trace back to one of these:

• Plumbing routed for convenience, not cold. A sink under a window on an outside wall, laundry moved into the garage, a bathroom added over a crawlspace. Those lines go years without trouble until a week-long cold snap parks over the state.
• Air leaks. Gaps at the rim joist, sill plate, dryer vent, or where a pipe passes through the wall pull outside air straight across the line.
• Missing or thin insulation in crawlspaces, garages, and exterior wall cavities, often in additions and finished basements.
• Deep thermostat setbacks overnight or while the family is away, which let exterior walls cool down.
• A vacant or lightly used house. No running water and no one to notice the first sign.
• Heat loss you don’t plan for: a furnace that quits overnight, a power outage, or a space that was heated last winter and isn’t now.
• Hoses left on spigots through the first hard freeze.

Do Frozen Pipes Always Burst?

No. Many frozen pipes thaw without damage. Whether one bursts depends on where the ice forms, how long it stays, and what condition the pipe was in before the cold hit.

What Happens When Pipes Freeze?

Water expands by roughly 9% as it freezes. Once an ice plug seals the pipe, the water trapped between that plug and a closed faucet has nowhere to go. As more ice forms, pressure in that trapped section climbs until the weakest point gives. That point is often a joint, a fitting, or a thinned spot downstream of the ice, not the frozen section itself. That’s why a frozen pipe in the garage can show up as a split fitting behind a kitchen wall.

Why A Frozen Pipe Can Burst After It Thaws

The split often happens while the line is frozen, but nothing leaks yet because the ice is holding the water back. When the line thaws, water reaches the crack and starts running. A homeowner waiting for the faucet to come back on can find water coming through a ceiling instead.

What Raises The Odds Of A Burst

• Repeated freezes on the same line. Each cycle stresses the pipe and its joints.
• Pipe already weakened by corrosion, pinhole wear, or a failure-prone material like polybutylene.
• High static pressure. A failing pressure regulator leaves less room for the extra pressure ice adds.
• Long freezes. A line frozen for a day is at more risk than one frozen for an hour.

Protecting Your Pipes Before A Cold Snap

Most frozen pipes are preventable, and the work is best done in the fall, before the first night in the teens. It comes down to three things: insulate the lines that sit in cold spaces, keep cold air off them, and keep heat moving through the house.

Insulate Exposed Pipes

• Use pipe-specific insulation. Foam or fiberglass pipe sleeves sized to the pipe’s diameter, fitted snug with the seams closed and taped, and no gaps at elbows and valves.
• Start where freezes happen: crawlspaces, unheated garages, basement rim joists, and any line running along an exterior wall you can reach.
• Cover both hot and cold lines. Either one can freeze.
• Consider heat cable on the worst runs. On a line that sits in a space you can’t heat, a listed, thermostatically controlled heat cable adds protection. Install it to the manufacturer’s instructions, and never wrap it over itself or under insulation it isn’t rated for.
• Insulation slows heat loss; it doesn’t create heat. A pipe in a space that drops well below freezing for days can still freeze inside its sleeve.

Seal The Air Leaks Around Pipes

A draft does more damage than cold air sitting still. Seal gaps where pipes pass through exterior walls and the rim joist, around dryer vents and hose bib penetrations, and in crawlspace vents and access doors that are left open.

Get Outdoor Spigots Ready

• Disconnect and drain garden hoses before the first hard freeze.
• If the spigot has an indoor shutoff valve, close it and open the outdoor spigot to let the line drain.
• If you have to do that every fall, ask about a frost-free sillcock, which keeps the shutoff inside the heated wall.

Keep Heat Where The Pipes Are

• Keep the thermostat steady day and night. Deep overnight setbacks let exterior walls cool off.
• Open cabinet doors under sinks on outside walls so room heat reaches the supply lines.
• Keep the garage door closed if any lines run through or above the garage.

Do You Drip Hot Or Cold Water To Keep Pipes From Freezing?

Drip the faucet fed by the exposed line. If you don’t know which side is at risk, drip both: on a single-handle faucet, set the handle in the middle so hot and cold both move. A slow, steady drip is enough. The point isn’t to keep the water warm, but to keep it moving and give pressure a way out if ice does form.

If You’ll Be Away

• Leave the heat on. Most utilities and insurers suggest keeping it at 55°F or higher while you’re gone.
• Have someone check the house during a cold stretch. A split line can run for days in an empty home.
• Will shutting off the water keep pipes from freezing? Closing the main limits the damage if a pipe splits, but the water already in the pipes can still freeze. For a longer absence, ask a plumber about draining the system.

How To Keep Pipes From Freezing Again

A pipe that freezes every winter is telling you something about where it runs or what it’s made of. Sleeves and dripping faucets work around that problem. The lasting fix changes the conditions. What a plumber looks at on a repeat freeze:

• Routing. Is the line inside an exterior wall, a crawlspace, or a garage when it could run through heated space? Rerouting a short section is often the permanent fix.
• Air leaks the homeowner can’t reach, inside finished walls, at the sill, or behind a cabinet.
• Pipe material and age. Galvanized, aging copper, and polybutylene don’t tolerate repeated freeze cycles well. In a house still on any of them, a freeze is often the first sign the system is near the end of its life. Our repiping page covers what replacement involves.
• The service line. A buried line that freezes where it enters the house may be too shallow or exposed at the foundation. Our water line guide explains how supply lines fail and when repair or replacement makes sense.
• Pressure. A regulator that has failed open keeps the system above where it should run, which leaves less room for freeze pressure.

New Jersey Resources For Frozen Pipes

• Your water utility. Call it when the whole house is out and the neighbors are too, or if the meter itself looks frozen or damaged. If your meter sits in an outdoor pit, keep the lid closed tight through the winter. Customers of a municipal water department should call that department.
• NJ 211. Dial 211 for help with heating bills and emergency heating assistance. Keeping the heat on is the first line of defense against frozen pipes. See NJ 211’s utility assistance programs.
• Home Energy Assistance (LIHEAP). The state’s Home Energy Assistance program helps eligible households pay for heating.
• License verification. Check a plumber’s NJ master plumber license through the Division of Consumer Affairs license lookup.
• Your local building department. Repiping or rerouting a water line generally needs a plumbing permit. Your plumber pulls it.

Frozen Pipe FAQs

What temperature do pipes freeze at?

Water freezes at 32°F, but pipes inside a house usually don’t freeze until the outdoor temperature falls to around 20°F. Lines in unheated spaces or in the path of a draft can freeze at warmer temperatures.

Will frozen pipes thaw on their own?

Often, yes, once temperatures rise. The risk is a crack that formed while the line was frozen and only starts leaking as the ice melts. That’s why it’s worth calling a plumber rather than waiting it out.

Can a pipe burst after it thaws?

Yes. Many splits happen while the pipe is frozen but don’t leak until the ice melts and water reaches the crack. That’s why a burst can surface hours after the cold has passed.

What thermostat setting prevents frozen pipes?.

Keep the heat steady rather than setting it back deeply at night. If the house will be empty, 55°F or higher is the common guidance. Pipes in unheated spaces still need insulation either way.

Can drain pipes freeze?

Less often than supply lines, because drains don’t hold water under pressure. Drain lines through unheated spaces, outdoor discharge lines, and traps in cold rooms can still freeze..

Does homeowners insurance in NJ cover frozen and burst pipes?

It depends on the policy. Many homeowners policies treat sudden water damage from a burst pipe differently from the cost of fixing the pipe itself, and some limit coverage when a home was left unheated. Check your policy or call your agent before you need it.

Who should I call about a frozen pipe?

An emergency plumber, right away. Treat a frozen pipe as an emergency even before anything leaks, because the line is under pressure and needs a plumber there when it releases, and especially if the frozen section is behind a wall or you see any bulge or split.

Frozen Pipes Are An Emergency: Call Arrow Sewer & Drain 24/7

Arrow Sewer & Drain’s licensed plumbers answer frozen and burst pipe calls 24/7 across Middlesex, Somerset, Morris, Essex, and Union counties. We’re on site while the line is under pressure: we find the frozen section, control the thaw so the water drains where it should, shut down a split line before it damages your home, and pressure-check everything before we leave, so a hidden crack doesn’t turn into a ceiling leak the next morning. If a pipe in your home keeps freezing, we’ll tell you why and what it takes to stop it.