How to Blow Out Your Sprinkler System — West Des Moines, Iowa
Complete checklist with climate-adjusted recommendations for West Des Moines, Iowa
Overview
Use an air compressor to blow water out of sprinkler lines before winter. Most residential systems need 50-80 PSI to clear water from the lines and prevent freeze damage.
Step-by-Step Guide
Turn off the water supply
Locate the main shut-off valve for your sprinkler system (usually near the water meter or in the basement). Close it completely. If your system has a backflow preventer, close both test cocks and the shut-off valves on either side of it.
Open the drain valves
If your system has manual drain valves at low points in the lines, open them to let gravity drain as much water as possible. Some systems have automatic drain valves that open when pressure drops. Let water drain for several minutes before proceeding to the blowout.
Connect the air compressor
Attach the compressor to the blow-out port (usually a threaded fitting near the backflow preventer or mainline). You need a compressor that delivers 50-80 PSI and at least 10 CFM (cubic feet per minute) for residential systems. Do not exceed 80 PSI -- higher pressure can damage PVC pipes and fittings.
Blow out one zone at a time
Using your sprinkler controller or manual valve, activate the zone farthest from the compressor first. Let the compressor push air through the lines until water stops spraying from the heads (usually 2-3 minutes per zone). Repeat for each zone, working from the farthest to the nearest.
Run each zone twice
After blowing out all zones once, go through the cycle a second time. Water can hide in low spots, and the second pass catches residual water that the first pass missed. You should see only dry air mist coming from the heads on the second pass.
Disconnect the compressor and close valves
Turn off the compressor and disconnect the air line. Close any manual drain valves you opened. Leave the controller turned off or set to rain mode for the winter. Some homeowners remove the backup battery from the controller.
Protect the backflow preventer
If your backflow preventer is above ground, insulate it with a foam cover or wrap it with insulation and a plastic bag. Leave the test cocks open at a 45-degree angle to allow any trapped water to expand without cracking the body of the unit.
What You'll Need
Tools
- - Air compressor (10+ CFM, capable of 50-80 PSI)
- - Compressor-to-sprinkler adapter fitting
- - Adjustable wrench
- - Screwdriver (for controller)
Materials
- - Insulation cover or foam wrap for backflow preventer
- - Teflon tape (for adapter fitting threads)
Cost Estimates
DIY Cost
$0 - $30 (if you own a compressor; adapter fitting if needed)
Professional Cost
$50 - $150
Safety Tips
- Never stand directly over a sprinkler head during blowout -- pressurized water and debris can be ejected forcefully.
- Wear safety glasses when connecting and operating the compressor.
- Do not exceed 80 PSI for PVC systems or 50 PSI for polyethylene pipe systems -- over-pressurization causes cracks.
- Never blow air through the backflow preventer -- connect downstream of it.
- Keep children and pets away from the yard during the blowout process.
When to Call a Professional
Hire a landscaper or irrigation specialist if you do not have an air compressor with sufficient CFM, if your system has more than 6 zones, or if you are unsure how your system is plumbed. Professional blowouts typically cost $50-$100 and take about 30 minutes.
Pro Tip
Timing matters -- blow out your system after the last watering of the season but before the first hard freeze (below 28 degrees F). In most northern climates, this means mid-October to early November. Set a calendar reminder so you don't forget.
Common Mistakes to Avoid
- Using too much air pressure -- exceeding 80 PSI cracks PVC fittings and damages seals.
- Using a compressor that is too small -- low CFM compressors cannot move enough air to clear the lines.
- Only blowing out each zone once -- always do at least two passes.
- Forgetting to insulate the above-ground backflow preventer.
- Leaving the controller running on its schedule through winter -- this can activate valves with no water and damage solenoids.
- Waiting too long and attempting blowout after the ground is already frozen.
Local Landscapers in West Des Moines
0Munoz Landscaping LLC
West Des Moines, IA
(515) 444-7401Griff Lawn And Landscape
West Des Moines, IA
(515) 577-3335Perficut
West Des Moines, IA
(515) 965-0951Founding Member
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West Des Moines Housing Market
Median Household Income
$84,925
Median Home Value
$286,300
Median Rent
$1,194/mo
Homeownership Rate
57.4%
Population
69,893
Median Year Built
1993
Source: U.S. Census Bureau, ACS 2023 5-Year Estimates
Fair Market Rents — West Des Moines
Studio
$1,063/mo
1 Bedroom
$1,109/mo
2 Bedroom
$1,318/mo
3 Bedroom
$1,794/mo
4 Bedroom
$1,841/mo
Source: HUD FY2026 Fair Market Rents — Des Moines-West Des Moines, IA HUD Metro FMR Area
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Related How-To Guides
How to Prevent Frozen Pipes
Keep cabinet doors open under sinks on exterior walls, let faucets drip during extreme cold, and take other precautions to prevent pipes from freezing and bursting.
How to Plan Spring Home Projects
Research contractors, get estimates, and schedule spring work now -- the best contractors book early. Winter is the ideal time to plan, budget, and line up help for warmer-weather projects.