Winterize Outdoor Taps and Irrigation in London, Ontario
To winterize outdoor taps in London, Ontario, disconnect every garden hose, shut off the indoor valve that feeds each outdoor tap, open the tap to drain it, then close it again. The City of London recommends shutting off outdoor water for winter even if you have frost-free faucets. Irrigation systems should be drained or blown out with compressed air, ideally by a professional, and backflow preventers must be protected and, for many systems, tested every year by a City-registered tester.
London's average first fall frost comes in early October, so by late October the clock is ticking before the first hard freeze. Here is a step-by-step guide for homeowners, landlords and property managers.
Why Outdoor Taps Freeze and Burst
When water freezes, it expands. A tap or pipe that still holds water at the outside wall can split as temperatures drop, and the damage often stays hidden until spring, when the water is turned on and starts leaking inside the wall or basement.
Common causes:
A garden hose left connected, which traps water in the tap
An outdoor tap that was never shut off from the inside
Supply pipes running through unheated garages, crawl spaces or exterior walls
Irrigation lines and backflow devices left full of water
The City of London's water by-law makes property owners responsible for protecting their plumbing from frost, including everything up to and including the water meter. In other words, a frozen pipe is generally the owner's problem to fix.
Step-by-Step: Winterizing Outdoor Taps
The City of London's "Beat the freeze" winterizing tips set out the basics:
Disconnect all garden hoses from outdoor faucets. Drain them and store them indoors.
Check whether you have a frost-free faucet. These have a longer stem that shuts off the water inside the heated part of the house.
If you do not have a frost-free faucet, shut off the outdoor water at the indoor valve, drain the tap by opening it, and then close the tap.
Shut off the outdoor water anyway. The City says it is good practice to turn off your outdoor water for the winter regardless of tap type.
Know where your main shut-off is. Shutting off the main valve is the best defence against flooding if you are going away.
Tips for older homes
Look for a small drain cap on the indoor shut-off valve. Opening it, with a bucket underneath, lets trapped water escape.
Insulate exposed pipes in unheated spaces, crawl spaces and exterior walls.
Seal gaps where pipes pass through exterior walls.
Winterizing an Irrigation System
Lawn sprinkler systems hold water in buried pipes, valves, sprinkler heads and the backflow preventer. If they freeze, repairs can be expensive. The City recommends checking your system's manual or calling your irrigation company.
Many contractors use compressed air to blow out the lines. Industry guidance from a landscape trade publication outlines the process:
Shut off the water supply to the system.
Connect the compressor after the backflow device and close the backflow isolation valves.
Start with the zone farthest from the compressor and work back, about two minutes per zone.
Use the right equipment: a compressor rated around 80 to 100 CFM for mainlines of 2 inches or less, and never more than 80 PSI.
Do not keep blowing air through dry pipe, which can overheat components, and wear eye protection.
Because too much pressure can damage pipes and heads, this is a job best left to a professional with the right compressor.
Backflow Preventers: London's Rules
Many irrigation systems have a backflow preventer that keeps irrigation water from flowing back into the drinking water supply. Under the City's water system rules:
Reduced-pressure, double-check and pressure-vacuum-breaker backflow devices must be tested by a City-registered tester when installed, cleaned, repaired or relocated, and every year.
Removing a backflow device without the City's permission is prohibited under the water by-law.
Installation and repair must be done by an Ontario-licensed plumber; some registered testers, such as irrigation installers, can only test.
Questions go to Backflow@london.ca or 519-930-2100.
Backflow devices are often above ground and exposed, so draining and insulating them is an important part of winterizing.
Vacant and Seasonal Properties
London's water by-law requires vacant or unheated premises to have the water shut off and the plumbing drained. That matters for:
Rental units between tenants
Seasonal businesses
Cottages and vacant homes
Garages, barns and outbuildings with water
The Insurance Bureau of Canada also advises shutting off and draining the water in a vacant home and insulating pipes in exterior walls and crawl spaces. Check your insurance policy, because many policies require the heat to be on or the water to be shut off and drained when a property is unoccupied.
Landlords and Property Managers: Who Does What
In rentals and multi-unit buildings, outdoor taps often get missed because everyone assumes someone else handled them. Put winterizing on the fall maintenance schedule and decide:
Who shuts off and drains outdoor taps on each building, and by what date.
Who books the irrigation blowout and the annual backflow test, and keeps the test report.
Where the main shut-off valves are, labelled, so staff or tenants can find them in an emergency.
How tenants report leaks or no water during cold snaps.
A simple checklist signed off each fall gives you a record if a burst pipe ever leads to an insurance claim.
Signs a Tap Froze Last Winter
If you missed winterizing last year, watch for these warning signs when you first turn the water back on in spring:
Water dripping or spraying inside the basement near the outdoor tap
A tap that runs even when closed, or will not shut off fully
Damp drywall, ceiling stains or musty smells near an exterior wall
Wet soil or pooling outside the foundation below the tap
Any of these call for a plumber before the leak does more damage.
What to Do If a Pipe Freezes
The City of London's water system page gives these steps:
Run several cold water taps. If at least one works, the problem is inside your plumbing, so call a plumber.
If no taps work, call the City at 519-661-4739.
The City may run a temporary water line from a neighbour's tap while the service thaws.
Owners are responsible for pipes from the building to the property line, and thawing frozen private service pipes is the owner's responsibility under the water by-law.
If a pipe bursts, shut off the main valve and contact your insurer as soon as possible. A City water demand manager told Global News in 2019 that the City's leak allowance program and many insurance policies may not cover losses caused by failing to winterize.
Fall Outdoor Water Checklist
Disconnect, drain and store hoses.
Shut off and drain every outdoor tap.
Blow out or drain the irrigation system.
Insulate or drain the backflow preventer, and book its annual test if required.
Insulate exposed pipes in unheated areas.
Find and label the main water shut-off.
Shut off and drain water at vacant or unheated buildings.
Clear gutters and extend downspouts so meltwater runs away from the foundation; see our guide to downspouts and sump pumps in London.
For the rest of the yard, use our fall yard prep checklist and our guide to fall leaf cleanup in London.
FAQ
When should I shut off outdoor taps in London, Ontario?
Before the first hard freeze. London's average first fall frost comes in early October, so late October is a good target for disconnecting hoses and shutting off outdoor water.
Do I need to shut off a frost-free outdoor tap?
The City of London says it is good practice to shut off your outdoor water for the winter regardless of tap type, and you should always disconnect hoses so water can drain.
Who fixes a frozen water pipe in London?
Owners are responsible for pipes from the building to the property line. If no taps in the house work, call the City at 519-661-4739; if some work, call a plumber.
Does my irrigation backflow preventer need testing?
In London, reduced-pressure, double-check and pressure-vacuum-breaker devices must be tested by a City-registered tester when installed or repaired and every year.
Can I blow out my own sprinkler system?
It is possible, but it takes a large compressor and careful pressure control. Industry guidance warns against exceeding 80 PSI, so most homeowners hire a professional.
Get Your Property Ready for Winter
SPM Landscape & Excavation has handled fall cleanups, property maintenance and winter services around London since 2006. We are WSIB covered with $1 million in liability insurance. See our services, then call (519) 474-0008 or email spmlandscape@gmail.com for a free quote.
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