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What size air compressor to blow out sprinklers

This job wants high volume at low pressure, which is the opposite of what a garage compressor is good at. Here is what a 6-gallon unit can and cannot do.

By Ryder M.Last updated Published
A lawn sprinkler head spraying water across grass

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Volume, not pressure

Why this job is different

Clearing an irrigation zone means pushing all the water out of a pipe with air. That takes a sustained volume of air moving through a large pipe at low pressure - the opposite of what a garage compressor is built for, which is modest volume at high pressure.

It is also a continuous load. You are not firing bursts; you are holding air into a zone until water stops coming out of the heads. A 6-gallon tank contributes for the first few seconds and then you are entirely on pump output.

So a small compressor does not fail at this job - it does it slowly, one zone at a time, with pauses. Which is genuinely workable for a small system and genuinely inadequate for a large one.

Published air demand at 90 PSI
ToolCFM @ 90 PSIAt loadDutyWhat the number means
Blow gun / dusting gun2.5 - 3-IntermittentIngersoll Rand lists 2.5 CFM, Engineering ToolBox 3. Held open continuously - clearing a sprinkler line, blowing out a filter - a blow gun empties a 6-gallon tank surprisingly fast.

Where two references publish different figures, both are shown rather than averaged into a number nobody published. Primary sources: Ingersoll Rand air consumption chart, Engineering ToolBox air tool consumption, and per-tool manufacturer specifications.

Do not damage the system

The pressure limit that matters most

Too much pressure is the real risk here, not too little. Irrigation components - poly pipe, valve diaphragms, spray head seals - have pressure limits well below what your compressor tank holds. Connecting a 150 PSI tank to a zone without regulating down can damage heads and fittings.

Your irrigation system's own documentation is the authority on its maximum pressure, and it varies by component. We are not going to publish a number for your system because we do not know what is in it, and a confident wrong number here costs you sprinkler heads.

What we will say clearly: use a regulator, set it before you connect, and check it with air flowing rather than static. And work through the largest-pipe zones first if you can, because they clear with less back pressure.

When to hire it out

If your system has more than a handful of zones, or long runs, or you are in a region where a missed pocket of water means a burst line, an irrigation contractor with a tow-behind compressor does the whole system in an hour. We would rather tell you that than sell you a compressor that technically can.

The picks

Compressors that make this practical

Quick picks

#ProductBest forScorePrice
1
A twenty-gallon vertical air compressor standing against a garage wall
Husky C201H 20-gallon4 CFM @ 90 / 20 gal / 175 PSI / 83 dBA4.0 CFM with 20 gallons at 175 PSI. The cheapest way to buy STORAGE rather than flow.
Burst automotive work where tank volume, not CFM, is the limit6.3/10★★★☆☆
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2
A thirty-gallon belt-drive air compressor with a cast iron pump
DEWALT DXCMLA1983054 30-gallon5.7 CFM @ 90 / 30 gal / 155 PSI5.7 CFM, 30 gallons, oil-lubricated cast iron and belt drive. Where a garage compressor stops being disposable.
A permanent garage compressor you expect to keep for a decade7.9/10★★★★☆
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3
A red six-gallon pancake air compressor on a garage floor
Porter-Cable C20022.6 CFM @ 90 / 6 gal / 150 PSIThe default answer to 'cheapest useful compressor'. 6 gallons, 2.6 CFM, 150 PSI, and it has been the same machine for years.
A first compressor for nailing, inflation and burst automotive work3.6/10★★☆☆☆
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4
A wall-mounted compressed air filter and regulator with a pressure gauge
PneumaticPlus SAW300 filter / regulator3/8" NPT / 53 SCFM / 10 micron53 SCFM, 10 micron, with a real gauge and a metal bowl. The single most useful small purchase in a garage air system.
One combined water trap and regulator at the wall5.3/10★★★☆☆
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Scores are computed from manufacturer-published specs by the rubric on our methodology page. Nothing here has been bench-tested, and we do not publish prices we cannot verify.

Pick 1 - Husky C201H

6.3/10★★★☆☆

Husky C201H 20-gallon

Best for: Burst automotive work where tank volume, not CFM, is the limit

Verdict

4.0 CFM with 20 gallons at 175 PSI. The cheapest way to buy STORAGE rather than flow.

What it does well

  • 20 gallons at 175 PSI is roughly six times the stored air of a 6-gallon 150 PSI pancake
  • 4.0 CFM at 90 PSI and 5.2 at 40 - enough to recover between bursts instead of chasing you
  • Vertical footprint takes a corner instead of floor space

What it will not do

  • 83 dBA published and a 7-minute fill from empty - plan to switch it on before you start
  • Oil-free at 20 gallons means a shorter pump life than a cast-iron oil-lubricated unit
How this 6.3 was calculated
MetricScoreWeightBasis
Air flow6.240%4 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air10.025%20 gal x 175 PSI = 3500, on a 125-3,500 scale
Noise0.715%83 dBA, on a 58-85 dBA scale
Portability5.010%No weight published - scored a neutral 5
Spec transparency6.710%4 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A twenty-gallon vertical air compressor standing against a garage wall

Licensed stock photo - illustrative of the category, not a photo of this unit

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Published specs

Husky C201H 20-gallon published specifications
CFM @ 90 PSI4
CFM @ 40 PSI5.2
Tank20 gal
Max pressure175 PSI
Noise83 dBA
Duty cycleNot published
Recoveryabout 7 minutes to fill from empty
PumpOil-free
Motor1.3 running
WeightNot published
Power120V

Source: Husky C201H 20-gallon compressor - retailer specification listing

Pick 2 - DEWALT DXCMLA1983054

7.9/10★★★★☆

DEWALT DXCMLA1983054 30-gallon

Best for: A permanent garage compressor you expect to keep for a decade

Verdict

5.7 CFM, 30 gallons, oil-lubricated cast iron and belt drive. Where a garage compressor stops being disposable.

What it does well

  • 5.7 CFM at 90 PSI and 7.0 at 40 - clears ratchets, die grinders and touch-up spraying
  • Oil-lubricated belt drive runs cooler and slower than a direct-drive oil-free pump
  • 120/240V, so it can move to a 240V circuit later

What it will not do

  • Oil-lubricated means an actual maintenance routine: check and change the oil
  • 155 PSI on 30 gallons stores less than 175 PSI on 20 in some comparisons - check the math, not the tank
How this 7.9 was calculated
MetricScoreWeightBasis
Air flow9.440%5.7 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air10.025%30 gal x 155 PSI = 4650, on a 125-3,500 scale
Noise5.015%Manufacturer publishes no dBA figure - scored a neutral 5, not a guess
Portability5.010%No weight published - scored a neutral 5
Spec transparency3.310%2 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A thirty-gallon belt-drive air compressor with a cast iron pump

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

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Published specs

DEWALT DXCMLA1983054 30-gallon published specifications
CFM @ 90 PSI5.7
CFM @ 40 PSI7
Tank30 gal
Max pressure155 PSI
NoiseNot published
Duty cycleNot published
RecoveryNot published
PumpOil-lubricated
Motor1.9
WeightNot published
Power120/240V

Source: DEWALT DXCMLA1983054 30-gallon compressor - product specifications

Pick 3 - Porter-Cable C2002

3.6/10★★☆☆☆

Porter-Cable C2002

Best for: A first compressor for nailing, inflation and burst automotive work

Verdict

The default answer to 'cheapest useful compressor'. 6 gallons, 2.6 CFM, 150 PSI, and it has been the same machine for years.

What it does well

  • 2.6 CFM at 90 PSI and 3.7 at 40 - the most common spec in the budget class for a reason
  • 6-gallon tank at 150 PSI stores enough air for real bursts of impact work
  • Two couplers, so two people or two tools without swapping

What it will not do

  • Porter-Cable does not publish a noise figure for it; the class sits in the high 70s to low 80s dBA
  • 2.6 CFM will not run a ratchet, die grinder or sander continuously
How this 3.6 was calculated
MetricScoreWeightBasis
Air flow3.640%2.6 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air2.325%6 gal x 150 PSI = 900, on a 125-3,500 scale
Noise5.015%Manufacturer publishes no dBA figure - scored a neutral 5, not a guess
Portability5.010%No weight published - scored a neutral 5
Spec transparency3.310%2 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A red six-gallon pancake air compressor on a garage floor

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

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Published specs

Porter-Cable C2002 published specifications
CFM @ 90 PSI2.6
CFM @ 40 PSI3.7
Tank6 gal
Max pressure150 PSI
NoiseNot published
Duty cycleNot published
RecoveryNot published
PumpOil-free
Motor0.8
WeightNot published
Power120V

Source: Porter-Cable C2002 - product specifications

Pick 4 - PneumaticPlus SAW300-N03BG-MEP

5.3/10★★★☆☆

PneumaticPlus SAW300 filter / regulator

Best for: One combined water trap and regulator at the wall

Verdict

53 SCFM, 10 micron, with a real gauge and a metal bowl. The single most useful small purchase in a garage air system.

What it does well

  • 53 SCFM at 3/8-inch NPT - it will not restrict any compressor on this site
  • 10 micron element plus a regulator in one piggyback body, so one mount does both jobs
  • Metal bowl and a 0-150 PSI gauge, with bracket included

What it will not do

  • 10 micron catches water and rust, NOT oil aerosol - it is not enough on its own for paint
  • Max operating pressure is 150 PSI, so it cannot sit upstream of a 175 PSI tank outlet
How this 5.3 was calculated
MetricScoreWeightBasis
Pressure headroom7.140%250 PSI rating, on a 125-300 PSI scale
Flow capacity2.240%53 SCFM, on a 40-100 SCFM scale
Spec transparency8.020%6 published specification figures
A wall-mounted compressed air filter and regulator with a pressure gauge

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

#ad Disclosure - we do not publish prices we cannot verify

Published specs

PneumaticPlus SAW300 filter / regulator published specifications
Port size3/8" NPT
Flow53 SCFM
Filtration10 micron
Max supply pressure250 PSI
Max operating pressure150 PSI
Gauge0-150 PSI, bracket included

Source: PneumaticPlus SAW300 filter/regulator - product specifications

Practical method

How to do it with what you have

  1. 01Shut off the water supply to the irrigation system and open a drain if it has one. Air is finishing the job, not doing all of it.
  2. 02Set a regulator to whatever your irrigation system's documentation specifies as its maximum safe pressure, checked with air flowing.
  3. 03Connect at the blow-out port, never at a sprinkler head. Systems that were designed to be blown out have a fitting for it.
  4. 04Work one zone at a time, opening only that zone's valve. Trying to do several at once divides the air and clears none of them properly.
  5. 05Run until the heads produce mist rather than water, then stop. Continuing to blow air through a dry zone heats the air and can damage seals for no benefit.
  6. 06Expect pauses on a small compressor while the tank refills. That is normal and it is why this takes an afternoon rather than an hour on a 6-gallon unit.

FAQ

Questions people actually ask

How many gallon air compressor to blow out sprinklers?

A 20-gallon unit at 4.0 CFM makes the job practical zone by zone; a 30-gallon at 5.7 CFM makes it comfortable. A 6-gallon pancake will do a small system slowly with frequent pauses. Volume matters here far more than tank size alone.

What PSI should I use to blow out sprinklers?

Whatever your irrigation system's own documentation specifies as its maximum safe pressure - components vary and we will not publish a number for a system we cannot see. Too much pressure damages heads and valve diaphragms, which is the real risk.

Can I blow out sprinklers with a pancake compressor?

For a small system, slowly, one zone at a time with pauses while the tank refills. Blowing out a zone is a continuous load, so after the first few seconds you are living on 2.6 CFM of pump output.

Should I hire someone to winterize my sprinklers?

If the system has more than a handful of zones or long runs, yes. A contractor with a tow-behind compressor clears a whole system in an hour, and in a hard-freeze region a missed pocket of water is an expensive repair.

Do I need to blow out sprinklers if I drain them?

That depends on your system's design and your climate, and it is an irrigation question rather than a compressor one. Some systems are designed to drain; many retain enough water in low spots to matter in a hard freeze.

Sources

Where these numbers come from

Accessed September 2026. If a figure on this page does not match the manufacturer's current sheet, tell us at contact@psiandhose.com and we will correct and date the change - see our editorial policy.

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