Backflow Testing & Prevention
Test and fix the assembly that stops irrigation water from flowing back into the home supply.
Homeowner guide
Winterize Outdoor Faucets and Sprinklers in Louisville, CO
Freezing weather shows up on the Front Range early and sometimes without warning. A short fall checklist keeps outdoor plumbing from cracking and leaking inside the walls, where you cannot see it.
By the Flatirons Express Plumbing team ·
Disconnect every hose
A hose left attached to a spigot traps water in the faucet. When it freezes, the ice pushes back into the pipe inside the wall. The faucet may look fine and the crack show up only in spring, as a leak behind drywall.
Remove hoses, splitters and timers before the first hard freeze. Store them drained. Cover spigots with insulated caps if you like, but the real protection is a drained faucet.
Freeze-proof spigots
A frost-free hose bib has a long stem so the valve seat sits inside the heated part of the house. It still must drain, and it drains only if the hose is off and the spigot slopes slightly downward. A hose attached defeats it.
If you have an older spigot with a shutoff inside, close the indoor valve, open the outdoor faucet and let it drain. Leave the outdoor one open through winter.
Blowing out the sprinklers
A sprinkler system holds water in its lines, valves and heads. A technician shuts off the supply, opens the drain valves and uses compressed air to push out the rest zone by zone. It takes a short visit and protects the whole system.
Do this in fall, before the first hard freeze. Doing it yourself with the wrong air pressure can damage heads, so many people hire it out. Ask the installer whether the backflow device is drained too.
Fall checklist
Work through these before the first hard freeze.
| Item | What to do | Why it matters |
|---|---|---|
| Hoses and timers | Disconnect and store drained | Trapped water freezes in the faucet |
| Hose bibs | Make sure each one drains | A cracked pipe leaks inside the wall |
| Sprinkler lines | Shut off and blow out with air | Water in the lines freezes and splits them |
| Backflow assembly | Drain or remove as directed | A cracked body fails the spring test |
The backflow preventer
The backflow assembly on the irrigation line is often above ground and can freeze and crack. Close the isolation valves, open the test cocks and drain it, or remove and store it if the manufacturer allows. Insulating covers help in mild cold only.
Read backflow testing and prevention for what to do in spring. A cracked body will fail the test and may spray water when you turn the system on.
Other outdoor items
Drain and store hoses. Shut off and drain any outdoor shower, fountain or pool and spa lines. If you have an outdoor kitchen, winterize the water supply to it. Cover exposed pipes in unheated outbuildings.
A hot tub that loses power in a freeze can crack its plumbing. See spa and hot tub plumbing for winter care.
A simple order of work
Start with hoses and timers, since they are quick. Then turn to hose bibs, then the irrigation system, then any outdoor kitchen or fountain. Work on a mild afternoon in the fall, not on the morning of the first freeze.
Keep a short note of what you did and what was left to do. If a technician is blowing out the sprinklers, book early, since appointments fill up when the first cold forecast arrives.
Signs that something froze
After a hard freeze, look for a hose bib that drips when it is turned off, a spigot that sprays from the stem or a stain on the interior wall behind it. These can point to a split pipe inside the wall, which leaks only when the water is on.
In spring, turn on the water and watch the meter. Walk the yard and listen at each valve box. A zone that does not pop up properly or a wet spot in the lawn suggests a cracked line. See leak detection if the meter moves with everything off.
Protecting what you cannot drain
Some outdoor fixtures, such as a hot tub or a pond pump, cannot simply be shut off. Follow the manufacturer's winter guidance, keep power available so freeze protection can run and have the equipment checked before the cold arrives.
If you are unsure how a particular system should be drained, ask a professional to show you once. A short lesson can save a repair. See spa and hot tub plumbing for more on winter care.
Costs of skipping the checklist
A split pipe behind a wall can run unseen until spring, and by then the damage to drywall and insulation is done. A cracked backflow body or a broken sprinkler line adds a repair bill to the cleanup.
Fall work takes an afternoon. Compared with a repair and the mess that follows, it is the cheapest part of owning a house with outdoor water. See burst pipe repair for what happens when a pipe does split.
Timing around Front Range weather
Early cold snaps can arrive well before winter, and warm spells return afterward. Do the work in October rather than waiting for a perfect day. If a warm stretch follows, you can reconnect a hose for a few days, then drain it again.
Watch the forecast for overnight lows. When freezing temperatures are expected, take hoses off that evening and let the faucet drain. The habit costs nothing and protects the pipe inside the wall.
Spring check
Turn the water back on slowly. Check each hose bib for drips and each zone for leaks. Look inside the house at walls near spigots for stains. If you notice a leak that was not there before, a freeze may have caused it.
Have the backflow device tested if your town requires it. A meter test finds leaks you missed. See leak detection if the numbers look wrong.
Quick answers
Winterizing questions
Before the first hard freeze. On the Front Range that is usually in October.
Disconnect the hose and make sure it drains. The hose is the main risk.
It is possible, but too much pressure damages the system. Many people hire a technician.
Shut off the water inside, thaw it slowly and check for leaks. Call if you see a split.
Services that connect to this topic
Burst Pipe Repair
Stop the flow, then mend the cracked pipe, often one that froze during the night.
Leak Detection
Pinpoint a concealed leak in a wall, a ceiling or the buried supply line, so only the right spot gets opened.
Keep reading
How to thaw frozen pipes safely
If water stops at a tap on a cold day, a pipe may be frozen. Here is how to thaw it safely and when to shut the water off.
Seven reasons a water bill climbs
A sudden jump usually has one of seven causes, from a running toilet to a sprinkler that stuck open.
Locating and closing the main shutoff
Every household member should know where the main water valve is and how it turns. Here is how to find it and what to do if it is stuck.
Winter coming and not sure what to drain?
Call and describe your outdoor plumbing. A dispatcher can connect you with a local contractor.