Sprinkler Blowout vs. Manual Drain: What’s the Difference and Which Do You Need?

Sprinkler Blowout

I talked with a homeowner in Castle Rock recently who had to pay hundreds to fix a broken pipe after they manually drained their sprinkler system the previous year. Technically, they didn’t do it wrong but more was needed because over time, very small amounts of water backed up into the outside pipe freezing and expanding causing the pipe to crack and drip small amounts of water into the backflow preventer where it eventually cracked.

That’s why every homeowner should understand the two main ways to winterize: a sprinkler blowout or a manual drain.

But what’s the difference between the two? And which one do you actually need for your yard?

Let’s break it down in simple terms.

Why Sprinkler Winterization Matters in Colorado

Here in Colorado—especially in places like Parker, Lone Tree, Castle Rock, Littleton, Highlands Ranch and the South Denver area—winter temperatures often drop well below freezing. When water freezes inside your sprinkler pipes, it expands. That pressure can split your PVC lines, crack valves, and even damage your backflow preventer as we shared previously.

Even a small amount of leftover water can cause big problems. That’s why sprinkler winterization is more than just “turning it off for the season.” It’s about making sure every drop of water is safely drained from your system.

There are two main ways to get water out of your sprinkler system before winter hits:

1. Manual Drain

2. Sprinkler Blowout (Air Compressor Method)

Both methods remove water from your irrigation lines, but they work in very different ways.

1. Manual Drain

A manual drain system has special valves installed in the irrigation lines that let water flow out by gravity. These valves are usually located at the lowest points in your system.

How It Works:

1. Turn off the water supply to your sprinkler system.

2. Open each drain valve one by one to let water flow out.

3. Open all zone valves on your sprinkler controller to release any trapped water.

4. Leave the valves open for a while to make sure everything drains fully.

Once the water stops flowing, you close the valves—and your system is ready for winter.

Pros of Manual Draining:

Simple – You don’t need special tools or an air compressor.
Free – You can do it yourself without hiring a pro.
No air pressure risk – There’s no chance of blowing out a fitting or damaging parts.

Cons of Manual Draining:

Not 100% effective – Water can still get trapped in parts of the system.
Requires correct setup – Your irrigation system must have manual drain valves installed at the right locations.
More risk in cold climates – In Colorado, where the ground freezes deep, any leftover water can cause pipe cracks.

Manual draining can work in warmer climates where pipes aren’t buried very deep—but it’s often not enough for Colorado homeowners.

2. Sprinkler Blowout (Air Compressor Method)

A sprinkler blowout uses compressed air to push water out of your sprinkler lines.

This is the most common and safest method for winterizing sprinkler systems in Parker and the South Denver area because it removes almost all remaining water—even from the deepest lines.

How It Works:

1. The water supply to the irrigation system is shut off.

2. A professional connects an air compressor to the sprinkler’s blowout port.

3. The technician opens one sprinkler zone at a time while air is gently forced through the lines.

4. Water is pushed out through the sprinkler heads until only mist comes out.

5. This process continues zone by zone until the system is completely dry.

Pros of a Sprinkler Blowout:

Best protection against freezing – Removes nearly all water from the system.
Works for all system types – Even if you don’t have manual drains.
Extends the life of your irrigation system – Prevents cracked pipes, split valves, and backflow damage.

Cons of a Sprinkler Blowout:

Needs the right equipment – You’ll need a high-powered air compressor, not a small home version.
Takes some know-how – Too much air pressure can damage sprinkler heads or fittings.
Usually best done by a pro – Hiring a company like Aspenwood Landscape ensures it’s done safely and correctly.

Which One Do You Need in Colorado?

If you live in Colorado, especially along the Front Range, a sprinkler blowout is almost always the best choice.

Our winters can be unpredictable. One week it’s 65 degrees, and the next we’re buried in snow. Because of our freeze–thaw cycle, leftover water in your sprinkler system can freeze multiple times throughout the season—each time putting more pressure on the pipes.

A manual drain might work in mild climates like parts of Texas or California. But here, the ground freezes deep enough to damage buried irrigation lines.

That’s why professionals across Parker, Castle Rock, and Highlands Ranch recommend scheduling a sprinkler blowout service every fall—usually between late September and early November.

How to Blowout Sprinklers Safely

If you’re curious about how the process works, here’s a quick overview.
(Keep in mind, this is not a full DIY guide, since using the wrong air pressure can cause expensive damage.)

Steps:

1. Turn off the irrigation water supply.
   Usually, this is a valve near your main water line or outdoor spigot.

2. Attach an air compressor to your sprinkler system’s blowout port.
   Most systems have a special fitting for this purpose.

3. Set the compressor pressure.
   Professionals typically use 50–80 PSI for PVC systems and 40–50 PSI for polyethylene systems.

4. Blow out one zone at a time.
   Open a single sprinkler zone from your control box.
   As the air flows, water will spray from the sprinkler heads.

5. Watch for mist.
   Once only mist or air is coming out, close that zone and move on to the next.

6. Turn everything off and disconnect the compressor.
   Finally, open any manual drain valves or test cocks to release leftover pressure.

If that sounds complicated—it is! That’s why most homeowners hire a pro for their Parker sprinkler blowout each fall.

Why Hire a Professional for Sprinkler Winterization?

At Aspenwood Landscape, we perform hundreds of sprinkler blowouts every year for homeowners across South Denver, Parker, and Castle Rock.

Here’s why it’s worth calling a pro:

1. Proper Air Pressure Control

Using too much pressure can destroy sprinkler heads or cause underground leaks. Professionals know exactly how much air each system needs.

2. Full-System Inspection

We check your valves, heads, and backflow preventer for leaks or damage—so you can fix small issues before spring.

3. Guaranteed Protection

If we blow out your sprinklers and you still have freeze damage (which is rare), we’ll help you get it fixed fast.

4. Save Time and Hassle

You don’t need to rent or transport an industrial air compressor. We bring everything to you.

5. Peace of Mind

You can relax knowing your irrigation system is safe all winter long.

Common Questions About Sprinkler Blowouts

How often do I need a blowout?

Once a year—every fall before freezing temperatures hit.

When should I schedule it?

The best time for sprinkler winterization in Colorado is from late September to early November. Don’t wait too long—once the first freeze hits, it may be too late.

Can I use my home air compressor?

No. Home air compressors usually can’t provide enough volume to push all the water out. Plus, they can easily over-pressurize the lines.

Do drip lines need to be blown out too?

Yes. Drip systems and smaller lines can also freeze. A professional can adjust air pressure for those zones.

What happens if I skip winterization?

You might not notice problems until spring—but by then, cracked pipes or valves can leak, causing soggy spots or low water pressure when you turn your system back on.

How Aspenwood Makes Sprinkler Blowouts Easy

Aspenwood Landscape makes the whole process simple. When you schedule your sprinkler blowout, here’s what you can expect:

1. Quick Scheduling – We’ll find a time that fits your fall schedule.

2. Professional Equipment – We use high-capacity compressors made for irrigation systems.

3. Efficient Service – Most systems are winterized in about 20–30 minutes.

4. Friendly Technicians – Our team treats your yard like their own, leaving it neat and tidy.

5. No Surprises – You’ll know the cost upfront, and there are no hidden fees.

What to Do After Your Blowout

Once your sprinkler system has been winterized:

• Turn off your sprinkler controller or set it to “rain mode.”

• Insulate your backflow preventer or above-ground pipes.

• Disconnect garden hoses and drain outdoor faucets.

• Make a reminder to call Aspenwood in spring for your sprinkler startup service.

These simple steps keep your irrigation system in top shape and ready for another green, healthy season next year.

The Bottom Line: Choose the Blowout for Colorado Winters

If you live in Colorado, there’s really no question—a sprinkler blowout is the safest and most effective way to protect your irrigation system.

Manual draining can work in mild areas, but here, where freezing temperatures are the norm, only a full sprinkler blowout gives you real peace of mind.

By scheduling your Parker sprinkler blowout with Aspenwood Landscape, you’ll protect your investment, avoid costly spring repairs, and keep your yard ready for another season of growth.

Ready to Schedule Your Sprinkler Winterization?

Don’t wait any longer, the first freeze has already happened! Contact Aspenwood Landscape today to schedule your sprinkler blowout service.

We’ll make sure your system is dry, protected, and ready to rest easy all winter long.