How to Winterize Your Jetter: Freeze Protection That Saves Your Pump

A cracked pump head is one of the most expensive, most avoidable mistakes in this trade. Water expands when it freezes, and a jetter pump, hose, and nozzle sitting full of water overnight in a cold truck or unheated shop is a repair bill waiting to happen. The fix takes fifteen minutes and a jug of antifreeze. Skip it once and you could be down for a week and out four figures on a rebuild.

This is a practical, plumber-to-plumber walkthrough of winterizing a jetter so your equipment survives the off-season — and so you can keep jetting through the cold months without destroying your gear.

Why Freeze Damage Happens (and Where)

Residual water is the enemy. After a job, water stays trapped in:

• The pump head and valves — the most expensive thing to crack
• The hose — including coil-buried sections on the reel
• The nozzle and its orifices/inserts — small passages that hold water and ice fast
• Unloader valves, gauges, and fittings

When that water freezes and expands, it splits castings and blows seals. The pump head is the heartbreaker because a crack there often means a full rebuild or replacement. The nozzle is cheaper to replace but a frozen, ice-plugged nozzle on a cold morning kills your first job of the day.

Method 1: Antifreeze Pull-Through (The Reliable Way)

This is the method most pros trust because it leaves protective fluid in every passage. Use RV/marine-grade propylene glycol antifreeze (the pink stuff) — it's non-toxic and pump-safe. Do not use automotive ethylene glycol; it's toxic and inappropriate for equipment that touches drain lines.

• Finish the day and relieve pressure. Shut down, open the trigger/valve to bleed off stored pressure.
• Disconnect the water supply. Drain the inlet/tank as much as you can.
• Feed antifreeze to the pump inlet. Put the inlet line into a bucket or jug of RV antifreeze.
• Remove the nozzle first, then run antifreeze through the open hose end. This is the safer approach: a nozzle's small orifices restrict flow and can spike pressure while you're trying to push antifreeze through at low speed, and on small inserts (down to M6) it's easy to leave an air pocket behind the jets. Pull the nozzle, run the pump on its low/bypass setting until you see steady pink antifreeze out the open hose end, then store the nozzle separately where it can drain and dry. Always follow your machine manufacturer's documented winterizing procedure where it differs.
• Cycle the unloader if your machine has one, so antifreeze reaches that valve too.
• Shut down with the system full of antifreeze. That's it — every wetted passage is now protected.

Catch and properly dispose of/recycle the antifreeze per local rules.

How much antifreeze? Enough to displace all the water in the system and see solid pink at the discharge — partial coverage isn't protection. A diluted, watered-down mix won't hold its freeze rating, so don't cut it. If your machine has a large tank or long onboard plumbing, plan for more than you'd think.

Why pink (propylene glycol) and not the green/orange automotive stuff? Beyond toxicity, propylene glycol is the right chemistry for equipment that contacts drain lines and that you'll flush back out in spring. Automotive ethylene glycol is toxic, and you do not want it in a system you use on customers' drains.

Method 2: Blow-Out (When You Can't Use Antifreeze)

If you don't have antifreeze on hand, a compressed-air blow-out removes standing water — but it's less foolproof because trapped pockets can remain.

• Relieve pressure and disconnect the supply.
• Use regulated low-pressure compressed air at the inlet to push water through the system and out the discharge.
• Open valves and the unloader to clear those passages.
• Remove the nozzle and blow it out separately — the small orifices and inserts hold water you can't see.

Blow-out is a reasonable stopgap, but for overnight or long-term cold storage, antifreeze is the safer bet. The weakness of blow-out is that pumps, unloaders, and elbows trap water that air skips past. If you're storing through a hard freeze, don't bet an expensive pump head on "probably got it all."

Hot-water / steam jetters: if you run a heated machine, it has additional water-holding components (coils, burner-side plumbing) that also need protection. Follow the manufacturer's procedure for those — they freeze and crack just like the pump.

Don't Forget the Nozzle and Inserts

Your nozzle is the part with the smallest, most freeze-prone passages. After any cold-weather job:

• Remove the nozzle and shake/blow out residual water. Standing water in tiny orifices freezes fast and can crack ceramic inserts or seize steel ones.
• Inspect inserts while it's apart. Winter storage is the perfect time to check for wear and swap worn ceramic or steel inserts so you're ready in spring. See the warning signs in jetterprosupply.com/blogs/the-pipe-pro-journal/5-signs-your-sewer-jetting-inserts-need-replacing.
• Store nozzles dry and indoors if possible.

Jetting Through the Winter Without Wrecking Gear

Plenty of cold-weather markets jet year-round. The trick is treating freeze management as part of every job, not just an end-of-season task:

• Keep water moving. Standing water in the hose between jobs freezes; idle = risk on a hard-freeze day.
• Store the rig warm overnight. A heated shop or insulated enclosure beats a cold open truck bed.
• Carry antifreeze on the truck in deep-freeze conditions so you can protect the system between jobs if you have to sit.
• Watch for ice-plugged nozzles first thing in the morning — never hit a frozen nozzle with full pressure. Thaw and clear it first.
• Mind frozen lines on the job. Jetting an ice-blocked line is a different animal than grease or roots; know what you're cutting before you push pressure into it.

Spring Startup: Flush Before You Run

When the season turns, flush the antifreeze out before your first real job:

• Reconnect clean water and run the pump on low to push antifreeze out (capture/dispose properly).
• Reinstall a clean, inspected nozzle with fresh inserts if needed.
• Check all fittings and seals for any winter weeping before you build full pressure.

For pump-care fundamentals that overlap with winter prep, see jetterprosupply.com/blogs/the-pipe-pro-journal/why-your-jetter-is-losing-pressure.

A Quick Off-Season Checklist

If you're parking the rig for the winter rather than running it, knock these out the same day you winterize:

• Pull and inspect every nozzle. Clear orifices, check inserts for wear, set aside any that need replacing so you can order before spring rush.
• Inspect the hose for jacket damage, soft spots, and kinks while you've got it off the reel.
• Check fittings and couplings for wear and proper rating.
• Note your insert/spare inventory. Winter is the cheap, calm time to restock consumables — not the morning of your first March callback.
• Drain and store any onboard water tank so nothing sits and freezes.

Doing the inspection while everything's apart for antifreeze saves you a second teardown later.

Bottom Line

A cracked pump head costs hundreds of times more than the antifreeze that would have prevented it. Build winterization into your routine: protect the pump, clear the hose, and never store a nozzle full of water. For broader cold-weather pump guidance, equipment manufacturers and pump makers publish freeze-protection procedures — follow your pump maker's spec where it differs from the general method here. pump manufacturer (e.g., Cat Pumps / General Pump) winterization guidance.

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Heading into the cold season? Now's the time to inspect and re-stock your nozzle inserts so you start spring ready. Shop replaceable ceramic and steel inserts and complete nozzles at jetterprosupply.com/collections/replacement-inserts and jetterprosupply.com/collections/sewer-jetting-nozzles.