When to blow out your sprinklers in Fort Collins, and what it costs

When to blow out sprinklers in Fort Collins

The city gives a clear answer. Fort Collins Utilities' residential water conservation page says to shut sprinklers off in early October and to winterize the system before the first freeze, which it says usually happens in early to mid October. It adds that shutting irrigation down early on a healthy lawn cuts community water use a lot.

The frost numbers back that up. The Old Farmer's Almanac frost date page lists October 2 as Fort Collins' first fall frost, using NOAA's 1991 to 2020 climate normals for the Fort Collins station. That date is set at a 30% chance, so roughly 3 years in 10 the first frost comes earlier than October 2.

In practice, that means booking your blowout in late September for an early October visit, so the system is empty before the first cold night rather than after it.

If it's later in October and your system still holds water, book the earliest visit you can and leave the system off until then. LawnStarter's guide explains why the timing matters: water expands when it freezes, and that can break pipes, sprinkler heads and valves. The longer water sits in the lines into November, the more hard freezes it has to get through.

What a sprinkler blowout costs

LawnStarter's sprinkler winterization cost guide (updated October 19, 2026) puts the average cost to winterize a sprinkler system at $59 to $144, and a blowout, the most thorough method, at $85 to $215. Most of the price comes down to how many zones you have:

A zone is one valve and the group of heads it runs. Your controller shows how many you have: count the stations it waters. LawnStarter notes that most front and back yards have two or more zones each, and side yards and shrub beds have one or two, so many houses have four zones or more.

LawnStarter puts a spring start-up, when a technician turns the water back on, raises the pressure slowly and checks for leaks, at $45 to $140, and a sprinkler tune-up at $75 to $120. Some companies sell the fall blowout and spring start-up together, so ask whether a quote covers one visit or both.

Blowout or drain: which one your system needs

There are three ways to get water out of a sprinkler system, and LawnStarter's guide prices each:

Draining only works if the system was built with drain valves, and LawnStarter points out that water can still collect in low spots of a drained system and freeze there. Some heads also have check valves that hold water in the line. That's why it says a blowout is usually recommended even on systems with automatic drains, and that skipping one isn't advised unless a qualified technician tells you otherwise.

Sloped yards make the case for a blowout stronger, because water settles in the lowest runs of pipe, and LawnStarter notes technicians may recommend a blowout when a slope keeps the system from draining. It also says a technician with a compressor putting out 80 to 100 cubic feet of air per minute can clear a zone in about five minutes, so most houses take well under an hour.

Protect the backflow preventer

The backflow preventer is the valve assembly where your sprinkler line leaves the house's water supply. It keeps water from the sprinkler pipes, which may carry fertilizer or pesticide, from flowing back into the water you drink. It usually sits above ground near the house, which is why the city's rules include protecting it from freezing.

Fort Collins Utilities sets these rules on its residential water page:

• Every sprinkler system must have an approved backflow preventer, and the approved models are listed at usclist.com.
• Not every backflow preventer sold locally is approved for Fort Collins, so ask the supplier.
• Have a certified tester check it at least every three years.
• Install a shut-off valve with a drain just above ground level, so the pipes can drain and the backflow preventer is protected from freezing.

LawnStarter lists a split backflow preventer alongside burst pipes and cracked valves as the repairs a proper winterization avoids. When the blowout is done, ask the technician to show you how they left the backflow valves and drain, so you know what to open in spring. Questions about the city's backflow rules go to cross-connection@fortcollins.gov.

Can you blow out sprinklers yourself?

You can, but it's not the savings it looks like. LawnStarter puts a rented air compressor at $30 to $60 a day, and says the compressor needs at least 20 to 25 cubic feet per minute of airflow to push all the water out. Check that rating before you rent or buy, because a compressor that can't move enough air leaves water sitting in the lines, which is the problem you were trying to fix.

LawnStarter's warning is short: improper winterization can lead to expensive repairs, and those repairs cost far more than the blowout. Most homeowners, it says, can drain a system for free, but clearing every line usually takes a blowout.

So the choice is mostly about risk. A small system on flat ground with drain valves is a reasonable do-it-yourself job for someone who's done it before. A system with many zones, a slope, or a history of cracked heads in spring is where paying a technician with a large compressor tends to cost less over a few years.

Either way, shut the water off to the system first, and don't turn it back on until spring. A line refilled after a blowout has to be cleared again before the next hard freeze.

After the blowout: watering through a dry winter

Turning the sprinklers off doesn't mean the yard stops needing water. Northern Colorado winters are often dry, and CSU Extension's fall and winter watering fact sheet (reviewed August 2025) says trees, shrubs, lawns and perennials can be damaged without extra water when there's little or no snow cover from October through March.

Water by hose, not by turning the system back on. The city and CSU give the same rules:

• Water only when the air and soil are above 40 degrees with no snow cover.
• Water at midday, so it soaks in before it can freeze at night.
• During long dry spells, water about once or twice a month.
• Disconnect hoses and store them inside after each use.

Trees matter most. The city's page says to give a newly planted tree 40 gallons every two weeks from mid October through November, then 40 gallons a month from December to mid April, and to water established trees twice a month during dry spells in fall, winter and spring. CSU adds that south and west facing lawns, new sod, and plants next to walls and fences dry out fastest.

Fort Collins sprinkler rebates to know before spring

If the blowout turns up a broken controller or worn heads, Fort Collins Utilities pays rebates on some water-saving sprinkler parts. Its residential page lists these:

The rules that matter: apply within 60 days of buying the part or finishing the project, funds are limited and paid first come, first served, and everything has to be installed at a Fort Collins Utilities residential water address. Some houses with a Fort Collins mailing address get water from a different district, so check your water bill before counting on a city rebate.

For a blowout, a spring start-up or repairs, NoCo Services does sprinkler and irrigation work in Fort Collins, Loveland and nearby cities. Have your zone count ready when you call, since it's the first thing any company will ask.