Our winters are exactly wrong for pipes
People from colder places sometimes laugh at how the DC area handles winter, but here is the thing they miss: our winters are harder on plumbing than theirs in one specific way. In Minnesota, builders assume deep cold and put the pipes where it cannot reach them. Around here, we get mild stretches broken up by two or three hard polar snaps a season, and a lot of our housing stock was built as if those snaps never come. Pipes run through exterior walls, unheated crawl spaces, garage ceilings, and attic edges all over Maryland, Virginia, and the District, and every January some of them freeze.
Water expands about nine percent when it turns to ice. Inside a closed pipe, that expansion has nowhere to go, and the pressure it creates can split copper, PVC, and even PEX fittings. The split usually happens where the ice forms, but the flood happens when it thaws, which is why so many burst-pipe calls come in on the warm afternoon after a cold night, right when everyone thinks the danger has passed.
The pipes that freeze first
After nearly three decades of winter calls across the DMV, the list of usual suspects is short and consistent:
- Hose bibs and the pipe feeding them, especially with a hose still attached holding water against the valve
- Lines in exterior walls, particularly kitchen and bathroom sinks on an outside wall
- Anything running through an unheated crawl space, which describes a huge number of older homes in Prince George’s and Charles County
- Pipes in garage ceilings under a bedroom or bonus room, common in NoVA townhome construction
- Attic runs and the top-floor supply lines near the roofline in DC rowhouses
- The main service line where it enters through an uninsulated rim joist
Notice what is not on the list: the pipes in your heated living space. A pipe in a 68-degree room does not freeze. Freezes happen where the building lets winter reach the plumbing, which means prevention is mostly about those specific weak spots rather than the whole house.
What actually works before the cold hits
Most of the effective moves are simple and cheap. In rough order of how much trouble they prevent:
- Disconnect garden hoses in the fall. A connected hose is the single most common cause of a split hose bib, because it traps water in the valve body where the frost reaches it
- Shut off and drain the hose bib lines from inside if your home has interior shutoffs for them
- Insulate exposed runs in crawl spaces, garages, and attics with foam pipe sleeves. It is a small job that pays for itself the first cold snap
- Seal the air leaks near pipes: gaps in the rim joist, crawl space vents that no longer close, holes where lines pass through exterior walls. Moving cold air freezes pipes far faster than still cold air
- If a frost-free hose bib was installed with the wrong pitch, it holds water and fails anyway. If yours drips inside the wall every spring, that is what happened, and it should be replaced
What to do during a hard snap
When the forecast shows single digits or a multi-day stretch below freezing, a few habits get families through without damage. Open the cabinet doors under sinks on exterior walls so room heat reaches the supply lines. Let the most vulnerable faucet run at a pencil-lead trickle overnight, because moving water resists freezing and the trickle relieves pressure if ice does start to form. Keep the heat at a steady temperature day and night instead of letting it set back deeply while you sleep. And if you travel in winter, never turn the system off. Set it no lower than 55 and have someone check the house during a cold stretch.
None of this costs meaningful money, and any one of these habits can be the difference between a normal week and a ceiling on the floor.
If a pipe freezes: the first five minutes
A frozen pipe announces itself as a faucet that suddenly gives you a trickle or nothing at all during a cold snap. Here is the order of operations:
- Find your main shutoff and make sure you can turn it, before you need it. It is usually where the water service enters the house, often near the water heater or the front foundation wall
- Open the affected faucet. That gives thawing water somewhere to go and relieves pressure in the line
- Warm the frozen section gently if you can reach it: a hair dryer, a space heater in the room, warm towels. Work from the faucet back toward the frozen spot
- Never use a torch or any open flame on a pipe. Every winter someone turns a frozen pipe into a house fire
- If you cannot find the freeze, cannot reach it, or the line has already split, shut off the main and call us
The moment you see water where it should not be, the main shutoff is the whole game. A burst supply line can put hundreds of gallons into a house in an hour. Shut it down first, then call. Our burst pipe repair and emergency plumbing crews run 24/7 through every cold snap, because that is exactly when the phone rings.
The repeat offender problem
If the same pipe freezes every winter, the house is telling you something specific. A line that freezes repeatedly is a line the building cannot protect, and the permanent fix is usually one of three things: insulating and air-sealing the cavity it runs through, adding heat tape rated for the application, or rerouting the line out of the cold path entirely. Rerouting sounds drastic and usually is not. Moving a kitchen supply line off an exterior wall is a modest job compared to one more February flood, and our frozen pipe repair work includes finding and fixing the reason it froze. Thawing it out and wishing you luck is not a repair.
Straight answers from a Master Plumber who has seen every version of this
Brandon is a licensed Master Plumber serving DC, Maryland, and Virginia with WSSC credentials and a BBB A-rating, and he has spent nearly thirty winters fixing what the cold does to plumbing around here. When we come out, you get an honest read on what happened, a clear price before any work starts, and a repair that holds. No hidden fees, no scare tactics, no upsell to the most expensive option when a simpler fix will do.
Get ahead of the next cold snap
If your home has a pipe that has frozen before, a crawl space full of bare copper, or hose bibs that have never been checked, deal with it in the fall on your schedule instead of in January on the weather’s. Call your 24/7 Master Plumber for the DMV at (202) 840-1998 any hour, or request a free quote through our contact page and we will get you winter-ready.