Key Points
- Drain a sprinkler system without the blowout method by using one of three techniques: manual, automatic, or indoor draining—each suited to specific system designs.
- Manual draining requires opening low-point valves; automatic draining uses valves triggered by pressure loss; indoor draining works through indoor shut-off and drain valves.
- Always drain the backflow preventer, inspect all zones, and close all valves to prevent freezing and damage in winter.
Draining Your Sprinkler System—Without the Air Pressure
Need to drain your sprinkler system, but don’t have an air compressor?
Wondering if there’s a safe way to do it without blasting air through the lines?
In this post, we’ll show you exactly how to drain your irrigation system without using the blowout method—using one of three alternative approaches: manual, automatic, or indoor draining.
Important: If you’re winterizing an irrigation system in Northwest Ohio or Southeast Michigan, Simmons Landscape and Irrigation strongly recommends the blowout method for full freeze protection. Deep freezes are common in this region, and compressed air is the most reliable way to prevent costly damage.
Still want to explore your options?
We’ll break each method down step by step—so you can make the best decision for your system and your home.
And if you’d rather skip the guesswork, just give Simmons Landscape and Irrigation a call or fill out our contact form to schedule your irrigation maintenance.
We’ve got your back before the first frost hits!
How to Drain a Sprinkler System Without the Blowout Method
Not every homeowner has a compressor in their garage—or wants to mess with one.
Thankfully, there are safe and effective ways to winterize your sprinkler system without blowing air through the lines.
The method you choose depends on how your irrigation system is set up.
Here’s a breakdown of your options:
Manual Drain Method
- Best for systems with valve boxes and manual drain valves at low points in the piping.
- You’ll need to open each valve manually and let the drained water escape by gravity.
- Often includes draining the backflow preventer and any lines above the frost line.
Automatic Drain Method
- Found in systems with valves designed to open when water pressure drops to zero.
- After you turn off the shut off valve, the system drains itself—no tools needed.
- You’ll still need to manually drain parts of the sprinkler system near the domestic supply or backflow preventer.
Indoor Drain Method
- Ideal for homes where the water supply for the sprinklers starts indoors—typically in the basement.
- You’ll use indoor valves to release water and protect your pressure vacuum breaker, test cocks, and pipes.
- Works well in newer homes with well-organized irrigation system designs.
Each of these methods helps ensure your system is drained properly and ready for a hard freeze.
But remember: some systems use a mix of these designs.
Follow the link to learn all the parts of an irrigation system.
If you’re not sure what type you have, it’s best to consult a pro before winter arrives.
⚠️ Important Note: If you live in Northwest Ohio or Southeast Michigan, keep in mind that deep freezes are common. That’s why Simmons Landscape and Irrigation strongly recommends the blowout method for full winter protection.
Step-by-Step Instructions for the Manual Drain Method
What Is the Manual Drain Method?
This method relies on gravity to empty water from your sprinkler system.
It’s common in setups with visible valve boxes, low-point drain valves, and piping designed to slope gently downward.
You won’t need any fancy equipment, but you’ll need to open multiple valves in the right order.
Step 1: Turn Off the Main Water Supply
- Find your shut-off valve, typically located near the domestic supply line or in a box outside.
- Make sure no additional water flow is entering the system during the drain process.
Step 2: Locate and Open Manual Drain Valves
- These are often found at the ends of zones, near low points in the ground.
- Open each valve slowly and allow the drained water to exit fully.
Step 3: Raise Sprinkler Heads (If Needed)
- Some sprinkler heads have built-in check valves that hold water unless raised.
- Gently lift the heads to let water escape—especially if you’re unsure whether they’ve drained properly.
Step 4: Drain the Backflow Preventer
- Locate the backflow preventer and open the two small test cocks using a flathead screwdriver.
- Adjust the ball valves at a 45° angle to allow air in and help flush out water.
- If there’s an air gap in the design, make sure it’s free of clogs or standing water.
Step 5: Close All Valves
- Once all the drained water is out, make sure all closed valves are sealed.
- This prevents cold air, debris, and pests from entering the system over winter.
How to Do the Automatic Drain Method
Not all sprinkler systems require you to open a bunch of valves by hand.
If your irrigation system was installed with automatic drains, this method could save you time and effort.
What Is an Automatic Drain System?
An automatic drain system uses built-in valves that open on their own once the water pressure inside your sprinkler system drops to zero.
This setup is common in systems with sloped piping or multiple zones where gravity helps with water movement.
If your system was installed this way, you won’t need special equipment to get started—just follow these simple steps.
Step 1: Shut Off the Water Supply
- Locate and close the main shut-off valve that feeds your irrigation system.
- This stops new water from entering and triggers the pressure drop needed to start draining.
Step 2: Relieve Pressure in the System
- Run a manual cycle on your sprinkler controller for just a few seconds.
- This removes any built-up pressure in the lines and allows the automatic valves to open.
Step 3: Inspect Drained Areas
- Walk your yard and check the low points in each zone.
- Look for signs of drained water near valve boxes or drain ports—this confirms the system is working.
Step 4: Manually Drain Any Remaining Water
- Some piping—especially near the backflow preventer and pressure vacuum breaker—won’t drain on their own.
- Open test cocks or small valves to release any trapped water in those sections.
- Always make sure the system is completely emptied before the first freeze.
How to Drain a Sprinkler System from Indoors
Indoor Drain Method Overview
This method is designed for sprinkler systems where the water source starts inside your house.
These systems usually include an indoor shut-off valve and a drain point near the domestic supply line.
It’s a clean and efficient way to clear out your system before winter, especially if you want to avoid cold-weather chores.
Step 1: Turn Off the Indoor Shutoff Valve
- Find the interior shut-off valve, typically near your water meter or basement utility wall.
- Close it to stop the flow of water to your outdoor irrigation system.
Step 2: Open the Indoor Drain Valve
- Place a bucket under the nearby drain pipe or spout.
- Open the valve to let water escape directly into the bucket.
Step 3: Open Petcocks on the Backflow Preventer
- Use a flathead screwdriver to open both test cocks on your backflow preventer.
- This step helps remove air locks and release any drained water still trapped inside.
Step 4: Adjust the Ball Valves
- Rotate both ball valves on the pressure vacuum breaker to a 45° angle.
- This ensures water can drain out and prevents damage if a hard freeze hits.
Step 5: Run a Manual Cycle on the Controller
- Run a brief test cycle on your controller.
- This can help remove any leftover water sitting in the lines or sprinkler heads.
Understanding the Importance of Backflow Preventer Protection
Why It Matters
Your backflow preventer is one of the most critical components in your sprinkler system—and also one of the most vulnerable to damage during freezing weather.
This device stops dirty water from flowing backward into your domestic supply, keeping drinking water safe.
Follow the link to learn about the different types of backflow preventers.
But because it’s usually above ground, exposed, and often near the side of your house, it’s highly susceptible to freezing and cracking.
Once damaged, a backflow preventer is expensive to replace and may require a full system shutdown to fix.
That’s why protecting it properly before winter hits is so important, especially in places like Toledo, where hard freezes are common and can hit fast.
How to Insulate and Protect the Device
- Wrap it up: Use insulation tape or foam pipe wrap to cover the piping and valves around the backflow assembly.
- Cover it completely: Place a weather-resistant bag or enclosure over the entire connection. Make sure it’s rated for cold temps.
- Leave airflow: Don’t seal the covering airtight—leave a small opening for ventilation so condensation doesn’t build up inside.
- Check the ground clearance: Ensure the device isn’t sitting directly on frozen ground, which can accelerate heat loss.
- Test yearly: In early spring, inspect for leaks or cracks before turning your sprinkler system back on.
Adding this layer of protection is a simple, effective step in the broader process of how to drain a sprinkler system without risking system failure later.
Important Tips for All Methods
Whether you’re going with a manual, automatic, or indoor approach, these best practices can help make sure your sprinkler system is fully prepped for winter and avoids freeze-related damage:
- Know your layout: Take time to determine how your system is built—where the shut-off valve, drain points, and water source are located. A quick search of your original system plans or a walkthrough can help.
- Check low points: Most water drain points are located at the lowest spots in your piping. Make sure they’re not blocked or buried.
- Inspect annually: Test each drain valve and connection to make sure they’re working before the first big freeze.
- Don’t rely on the controller alone: Running a manual cycle helps relieve pressure, but it doesn’t drain everything.
- Leave no trapped water: If even a small amount remains in a section of underground piping, it can expand and crack during a freeze, leading to costly repairs in the spring.
These tips are the key to protecting your system now and saving money on repairs later.
When to Consider Professional Help
There are times when DIY just isn’t the safest or smartest option, especially when it comes to preventing expensive repairs to your sprinkler system.
If you live in Northwest Ohio or Southeast Michigan, where underground piping faces repeated freeze cycles, professional winterization services may be your best move.
Call in the Pros If:
- You’re unsure what type of drain method applies to your system
- You can’t find or access all the zones, valves, or the main shut off
- The piping layout is complex, deeply buried, or poorly labeled
- Parts of your system are below the frost line or don’t appear to drain on their own
- You’ve had issues with freezing, cracked pipes, or failed backflow preventers in past winters
Letting a trained technician handle the process gives you peace of mind.
They’ll also inspect for wear, leaks, or signs that it might be time to replace certain components before spring.
A professional can also perform the blowing method correctly with a commercial-grade compressor, ensuring your entire system is fully emptied.
It’s a quick service, often done in under an hour, and it can help you avoid much bigger repair bills in the months ahead.
Common Mistakes to Avoid
Even small missteps can leave water trapped inside your sprinkler system—and just a little leftover moisture is enough to cause a burst pipe or broken valve during a deep freeze.
Avoiding these common errors is a must for homeowners:
Mistakes That Can Cost You:
- Forgetting to shut off the main water line—If the shut-off valve stays open, new water can refill lines you’ve already drained.
- Leaving sprinkler heads pressurized – Not running a short manual cycle can trap pressure, preventing proper drainage.
- Skipping the backflow preventer – This device is often overlooked but is one of the most expensive parts to replace if damaged.
- Relying only on the controller – The controller can relieve pressure, but won’t fully drain all zones or underground piping.
- Not closing valves afterward – Leaving them open lets in cold air, debris, and even pests that can block or damage the system.
- Not using the blowout method in freeze-prone regions – In areas like Northwest Ohio and Southeast Michigan, where hard freezes are common, skipping the blowing method can leave water behind in your system, leading to cracked piping and costly repairs come spring.
Frequently Asked Questions About Draining a Sprinkler System
Where is the water shut-off valve for my sprinkler system?
The shut-off valve is typically located near where your sprinkler system connects to the domestic supply.
In most homes, it’s in the basement, crawl space, or utility room—often close to the water meter.
For outdoor setups, you might find it inside a valve box buried near your home’s foundation.
Can I winterize my sprinkler system without a compressor?
Yes—if your system has manual or automatic drain valves and you live in an area that doesn’t get significant freezes, you can complete the process without using a compressor.
However, in regions like Northwest Ohio and Southeast Michigan, where deep freezes are common, skipping the blowing method increases the risk of damage unless you’re sure the piping has drained properly.
What happens if some water is left in the lines?
Even a small amount of water left behind can freeze, expand, and crack your underground piping, valves, or backflow preventer.
That’s why it’s essential to follow each step carefully—or contact a professional if you’re unsure the system is fully cleared.
Don’t Let Your Sprinkler System Freeze—Let Simmons Landscape and Irrigation Handle It
If you’d rather skip the guesswork, Simmons Landscape and Irrigation offers professional winterization services to make sure your sprinkler system is fully protected.
Whether your system needs a winterization service or just a seasonal inspection, our irrigation experts are ready to get it done right the first time.
