Outdoor Faucet Burst Over the Winter: The Leak You Don't See Until Spring

An outdoor faucet that freezes over the winter usually does not leak in January. It leaks in April, the first time someone turns it on to fill a bucket or wash the car. The pipe split months ago, inside the wall or the basement ceiling, but water only flows through the crack when the tap is open. So the first sign is often a wet basement ceiling, a soaked header or water running down the foundation wall while the hose is on.

Why outdoor faucets split in the first place

Most newer Ontario homes have frost-free outdoor faucets. The handle is outside, but the actual valve sits at the end of a long stem inside the heated part of the house. When you close it, the water in the stem drains out through the spout, so there is nothing left in the cold section to freeze.

That only works if the water can drain. A garden hose left attached, or a splitter or shutoff screwed onto the spout, traps water in the stem. That water freezes, expands and splits the stem or the pipe behind it. Nothing happens until spring, because the valve inside is still closed and holding pressure back.

Older homes often have a standard outdoor faucet with a separate shutoff valve inside the basement. If that inside valve is left open, the exposed section of pipe stays full of water all winter and freezes the same way.

Signs your outdoor faucet froze

• Water dripping from the basement ceiling or running down the foundation wall when the outside tap is on.
• Low flow at the spout, or water spraying from around the handle or the siding.
• A water stain on the basement ceiling directly behind the faucet location.
• A musty smell in the basement near the outside wall where the faucet is, in spring or early summer.
• Damp or crumbling drywall, or a stained header board, behind the faucet.

What to do if it leaks when you turn it on

1. Turn the outside tap off right away. With a frost-free faucet that stops most of the flow.
2. If water keeps coming, close the inside shutoff for that line, or the main water shutoff.
3. Look at the ceiling and wall behind the faucet. Move anything stored below it.
4. Call a plumber to replace the faucet or the split section of pipe.
5. Before closing anything up, have the wall cavity and ceiling checked with a moisture meter.

The repair is usually simple. The problem is how long the water ran before anyone noticed. Ten minutes of a hose running into a split stem can soak the insulation in the header and wet the drywall below. Because it happens in spring, a lot of people dry the surface with a towel and move on. The insulation stays wet behind the drywall and mold grows by summer.

How much damage to expect

A short leak caught right away often needs nothing more than a moisture check and a few days of drying. A leak that ran for an hour, or one that went unnoticed through several uses, usually means wet insulation in the header, wet drywall on the ceiling and sometimes wet carpet below. Our water damage drying jobs run $1,500 to $11,000 depending on how far the water travelled, and a leak like this usually sits at the low end. A moisture inspection on its own runs $249 to $549.

The two-minute fall fix

• Disconnect every hose, splitter and timer from outdoor faucets before the first hard frost.
• If you have an inside shutoff for the outdoor line, close it and then open the outside tap to drain the pipe. Leave the outside tap open for the winter.
• If you are not sure whether your faucet is frost-free, look for an inside shutoff valve on the line. If there is one, use it.
• Add an insulated faucet cover if the spout is on a windy north or west wall.
• Put a leak sensor on the basement floor below the faucet location.

If your faucet sprayed water inside the wall this year, or you are not sure whether it did, send us a photo of the ceiling or wall behind it. We will tell you whether it needs a moisture check before the drywall gets closed up or painted over.

Common questions