You’ve just heard your plumber say, “I’ll install a blowout,” and now you’re wondering—what on earth does that mean? Don’t worry—you’re not alone. Many homeowners hear this phrase during fall service calls and assume it’s something dramatic (like a pipe explosion!). In reality, “if a plumber installs a blowout” refers to a routine—but critical—winterization procedure. This article breaks down exactly what it means, why it’s done, and how it protects your plumbing system from costly freeze damage.
What Exactly Is a “Blowout” in Plumbing?
Despite the alarming name, a plumbing blowout has nothing to do with explosions or emergencies. Instead, it’s a controlled process used to remove water from outdoor or seasonal plumbing lines—typically before winter arrives.
🔧 Industry Insight: According to the Insurance Institute for Business & Home Safety (IBHS), frozen pipes cause over $1 billion in property damage annually in the U.S. A blowout is one of the most effective preventative measures.
During a blowout, a plumber uses an air compressor to force compressed air through irrigation systems, outdoor faucets, or pool lines. This pushes out residual water, preventing it from freezing, expanding, and cracking pipes when temperatures drop below 32°F (0°C).
Think of it like blowing through a straw to clear liquid—except with professional-grade equipment and precise pressure control.
Why Would a Plumber “Install” a Blowout?
Technically, plumbers don’t install a blowout—they perform or conduct one. The phrasing “install a blowout” is a common misstatement. What they actually do is:
Connect an air compressor to your system’s blowout port (often near the main shut-off valve).
Close all valves except those leading to lines needing winterization.
Gradually introduce air at 40–80 PSI (pounds per square inch)—never exceeding 80 PSI to avoid damaging fittings.
Open each zone or faucet one by one until only air (no water) comes out.
Seal or cap exposed outlets to keep moisture out during winter.
This process usually takes 30–60 minutes, depending on system complexity.
📌 Pro Tip: Always hire a licensed plumber for this task. DIY attempts with improper pressure can crack PVC pipes or damage backflow preventers.
When Is a Blowout Necessary?
Not every home needs a blowout—but if you have any of the following, you likely do:
Frost-free hydrants in extremely cold climates (Zone 5 and below)
The general rule? If water sits in pipes exposed to freezing temps, it must be removed.
System Type
Blowout Needed?
Risk if Skipped
Indoor bathroom pipes
❌ No
Low (if heated)
Sprinkler system
✅ Yes
High—burst lines, soggy lawn, $2k+ repairs
Hose bibb (standard outdoor faucet)
⚠️ Maybe
Medium—depends on insulation
Pool return lines
✅ Yes
Very high—structural damage possible
For reference, the U.S. Department of Energy recommends winterizing outdoor plumbing when nighttime temps consistently fall below 28°F for 6+ hours.
How a Blowout Differs From Other Winterization Methods
Some homeowners drain systems manually or use antifreeze. But these methods have limitations:
Manual draining often leaves water trapped in low spots or elbows.
Non-toxic antifreeze works for indoor fixtures (like toilets) but isn’t safe or effective for irrigation systems.
Blowouts are the gold standard for pressurized outdoor lines because they remove >95% of standing water.
💡 Real-World Example: In 2023, a Colorado homeowner skipped a blowout to save $150. A sudden November freeze cracked three sprinkler lines—resulting in a $3,200 repair and ruined landscaping.
Step-by-Step: What Happens During a Professional Blowout
Here’s exactly what a licensed plumber will do:
Shut off main water supply to the system being winterized.
Open manual drain valves (if present) to release initial water.
Attach air compressor to the designated blowout fitting (usually a threaded port near the backflow device).
Set compressor to 50 PSI—safe for most PVC and polyethylene lines.
Activate zones sequentially:
Zone 1: Run air for 2–3 minutes until dry.
Repeat for all zones (typically 4–8 in residential systems).
Disconnect compressor, close all valves, and insulate exposed components.
Document completion and advise on spring reactivation.
⚠️ Never use shop compressors over 100 PSI—this can rupture fittings. Professionals use regulated, oil-free compressors designed for plumbing.
Common Misconceptions About “Blowouts”
Let’s clear the air (pun intended):
❌ Myth: “Blowouts damage pipes.” ✅ Truth: Done correctly, they’re safer than leaving water to freeze.
❌ Myth: “I can just leave my sprinklers off in winter.” ✅ Truth: Residual water still freezes—even if the system isn’t running.
❌ Myth: “Only northern states need this.” ✅ Truth: Texas, Georgia, and even California experience freeze events that crack pipes (e.g., Winter Storm Uri in 2021 caused $195M in plumbing claims).
FAQ Section
Q1: Does “install a blowout” mean the plumber is fixing a burst pipe?
A: No. Despite the word “blowout,” this is a preventative service, not an emergency repair. It’s about avoiding bursts—not responding to them.
Q2: How much does a plumbing blowout cost?
A: Typically $75–$150 for a standard residential sprinkler system. Larger properties or complex setups may cost up to $250. Far cheaper than freeze damage repairs!
Q3: Can I do a blowout myself?
A: Technically yes—if you own an air compressor and understand your system. But most manufacturers void warranties if non-professionals perform winterization. One mistake can cost thousands.
Q4: When should I schedule a blowout?
A: Before the first hard freeze. In most U.S. regions, that’s late October to mid-November. Check your local 10-day forecast—schedule when temps are predicted to drop below 28°F.
Q5: What if I forget to get a blowout?
A: If a freeze is imminent, shut off the water supply and open all outdoor faucets to drain as much as possible. Then call a plumber immediately—they may still be able to perform an emergency blowout.
Q6: Is a blowout the same as “blowing out” a gas line?
A: No. Gas line purging uses nitrogen and follows strict NFPA codes. Plumbing blowouts use compressed air on water lines only—never mix the two!
Conclusion
So, if a plumber installs a blowout, it simply means they’re safeguarding your outdoor plumbing against winter’s icy grip—not causing chaos! This quick, affordable service can save you from devastating water damage, mold growth, and landscape destruction.
Don’t wait for the first frost to act. Schedule your blowout early, especially if you live in a region with unpredictable cold snaps. And if you found this guide helpful, share it with a neighbor—they might thank you when their sprinklers survive January intact!
💬 Have questions? Drop them in the comments below—or tag a friend who just said, “My plumber did a blowout… huh?”
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