How to Winterize Your Sprinkler System in Franklin, TN: 6 Steps Before the First Freeze

When to winterize your sprinkler system in Franklin, TN

Winterize between late October and early November. At the very latest, finish before the first hard freeze, which averages Nov 15 at 28°F in Nashville^[1].

The dates come from NOAA’s 1991–2020 climate normals for Nashville International Airport^[1]. The average first 32°F night is Nov 3. But that is only the middle of the range. In one fall out of ten, the first freeze has already come by Oct 22.

Why a mild Tennessee winter still cracks pipes

Franklin is in USDA zone 7b, where the coldest winter night averages 5 to 10°F^[6]. That is cold enough to freeze any water left in your system.

The parts above ground freeze first: the backflow preventer, exposed pipe and valves. They sit in open air with no soil around them.

In Franklin, the parts of your sprinkler system you can see are the parts that freeze first.

A simple rule for your calendar

Pick a dry weekend in the last week of October or the first days of November. If you hire it out, book in October so the work is done before the first freeze.

How to winterize a sprinkler system in 6 steps

The job has six steps: shut off the water, turn off the controller, empty the lines, set the backflow valves to half open, drain the parts above ground, and insulate what stays exposed. These steps follow Rain Bird’s homeowner guide^[2].

1. Shut off the water at the main irrigation valve. This is the valve that feeds only your sprinkler system, not the house. Close it all the way.
2. Set the controller to off or rain mode. This stops the timer from opening a zone while the lines are empty.
3. Drain or blow out the lines. Use your system’s drain valves, or push the water out with compressed air. Keep the air at or below about 50 psi for poly pipe and 80 psi for PVC^[3].
4. Turn the backflow ball valves to half open (45°). Open the small test cocks too. Family Handyman lists this as its own step: “Turn Your Valves to 45 Degrees”^[3].
5. Drain the parts above ground. Empty the backflow preventer and any exposed pipe so no water sits where cold air can reach it.
6. Insulate the backflow preventer and exposed pipes. Wrap them with pipe insulation or an insulated cover made for backflow devices.

Rain Bird, Hunter and Orbit controllers

The six steps are the same for every brand. Only the controller step changes. Look for an off position or a rain mode on the dial or screen, and check the maker’s manual if you cannot find it.

Drain-down or blowout: pick the method that fits your system

Use a drain-down if your system has drain valves. Use a compressed-air blowout if it has a blowout port and you own a compressor with a pressure regulator. Both methods aim for the same result: no water left in the pipes.

What psi to use for a sprinkler blowout

Set the regulator before you connect the hose. Keep it at or below about 50 psi if your lines are flexible black poly pipe, and at or below about 80 psi for rigid PVC^[3]. If you do not know which pipe you have, use the lower number.

How to winterize your backflow preventer

Turn its ball valves to half open (45°), open the test cocks, drain it, and wrap it in insulation. The backflow preventer usually sits above ground, so it is the first part of your system that cold air reaches.

The backflow preventer stops a cross connection between your sprinkler water and your drinking water. Utilities can require it on permanent irrigation. Your water utility sets the rules for it, including how often it needs a test.

What a local utility requires

Milcrofton Utility District, for example, tells its customers: “Permanent lawn irrigation systems … a Reduced Pressure backflow preventer is required to prevent any cross connection between your system and potable water. This device shall be tested annually.”^[5]

Rules differ from one utility to the next. Check with the utility named on your water bill for its test schedule and its list of approved testers.

How to insulate it well

Cover the whole device, the exposed pipe below it and the valve handles. Use pipe insulation, an insulated pouch made for backflow preventers, or both. Make sure the cover stays on through wind and rain.

DIY or hire a pro: sprinkler winterization cost in Nashville

Hiring it out costs about $101 on average in the Nashville area, with typical jobs from $50 to $115, according to Angi^[4]. Doing it yourself costs your time plus the right tools.

When you compare quotes, ask what is included: the blowout or drain-down, the backflow valve setting, insulation of exposed parts, and the controller set to off or rain mode. A full job covers all six steps.

See what Pineda Properties does on its irrigation services page.

Keep your pipes whole: 5 winterizing mistakes to skip

Five slips put water and cold in the wrong place: waiting too long, a timer left on, too much air, bare parts above ground, and standing in the line of air. Skip all five.

When to turn your sprinklers back on in spring

Start your system after the last freeze. In Nashville the last 32°F night averages Mar 31, and after Apr 16 the chance of another one drops to 10%^[1]. Mid-April is the low-risk window for Franklin.

1. Remove the insulation and close the test cocks. Check the backflow preventer for cracks before water reaches it.
2. Open the valves slowly. Let water fill the lines a little at a time.
3. Check every head. Run each zone and look for broken, buried or tilted heads.
4. Set the controller. Take it out of off or rain mode and set the schedule for spring.

Spring start-up lines up with planting season. Our Middle Tennessee planting calendar shows what to plant once the freeze risk is behind you.